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Key Concepts. Function Vs. Process Function  why does a system exist, its purpose, what is does for the organism (teleological approach) Process How does a system perform its function, (mechanistic approach)

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Key concepts

Key Concepts

Function Vs. Process

  • Function why does a system exist, its purpose, what is does for the organism (teleological approach)

  • Process How does a system perform its function, (mechanistic approach)

    PHYSIOLOGY integrates both approaches to understand “How” physiological systems work, and “Why” they are there


Key concepts1

Key Concepts

  • Homeostasis Maintaining the internal environment of an organism relatively stable by maintaining certain properties within a normal range

  • E.g. Temperature, blood glucose, blood pressure, salt concentrations, pH


Homeostasis

Homeostasis

  • Keeping these parameters around a set point requires constant monitoring, compensation, and energy input. E.g. Like driving a car straight requires many corrections with the steering wheel

  • Additionally set points may change, either due to biological rhythms or in response to environmental change


Tissue types

Tissue Types


Cell to cell communication

Cell to Cell Communication

Add Red Dye to left cell

Connexon


Cell to cell communication1

Cell to Cell Communication

Paracrine

Target Cell

Cell

Autocrine

Endocrine

Blood


Receptors

Receptors

  • Signalling specificity depends on Receptor Proteins

  • Signalling molecule binds onto a specific receptor found only on target cells transmembrane, cytosolic, or nuclear location

  • Receptor protein is what brings about the response to signal

  • Agonists Binds receptor and activates response

  • Antagonists  Binds receptor and produces no response (inhibitory activity)


Receptors1

Receptors

Biological Signalling Molecule

Foreign “drug” molecule

Foreign “drug” molecule

Antagonist Pathway Without Response

Normal Signal Pathway With Response

Agonist Pathway With Response


Nervous system

Nervous System

  • 1) Receives information  Sensory neurons from external environment (light, sound, pressure etc)

  • 2)Integrates Information  Organizes new information, combines with stored information

  • 3) Transmits Information Sends signals to muscles/glands to carry out action


Neurons

Neurons

Dendrites

Axon Terminal

Node of Ranvier

Soma

Myelin Sheath/ Schwann Cell

Axon

Nucleus

Ref: Wikipedia

http://en.wikipedia.org/wiki/File:Neuron_Hand-tuned.svg


Neurons1

Neurons


Neurons2

Neurons


Nervous system1

Nervous System


Glial cells

Glial Cells

Neurons

Neurons are the VIP’s of the nervous systems! They need other people to help do their laundry, cook food, act as bodyguards, etc etc so they can focus on their jobs


Pns glial cells

PNS Glial Cells

Schwann Cells  form myelin sheath which acts as electrical insulator. Only wrap around 1 cell

  • Structure has many layers of cell membrane with gap junctions connecting layers

-Gap Junctions

Neuron


Pns glial cells1

PNS Glial Cells

  • Satellite Cells  non-myelinating, support nerve cells


Cns glial cells 4 types

CNS Glial Cells-4 Types

  • Oligodendrite Myelinating Cell (like Schwaan) but can wrap around more than one neuron

  • Astroglia  Make contact with blood vessels and neurons; transfer nutrients, maintain microenvironment; Star Shaped.


Cns glial cells

CNS Glial Cells

  • Microglia Small, specialized immune cells -maintain microenvironment like astroglia

    -remove dead cells & foreign invaders, protect neurons

  • Ependymal Cells  Epithelial cells, create semi-permeable barriers between brain compartments

    -produce cerebrospinal fluid


Electrical properties of neurons

Electrical Properties of Neurons

  • Difference between electrical charge on the inside of the cell and the outside environment creates an electrical gradient across the membrane

  • There is also an osmotic gradient due to the differences in concentrations of solutes between the inside & outside of cell


Electrical properties of neurons1

Electrical Properties of Neurons

  • Cell membranes are semi-permeable

    • Allow free diffusion of small, hydophobic (non-polar) molecules

  • Membranes a impermeable to most molecules, Especially charged ions.

  • Specific protein transporters move these molecules across the membrane


Resting membrane potential

Resting Membrane Potential

  • Resting Membrane Potential for a neuron is around -70 mV to -90 mV  Negative charge compared to environment; mostly due to phosphate (HPO42- ,H2PO4-), and negatively charged proteins & DNA

+

+

+

-

+

-

-

-

+

+

-

-

-70 mV

-

+

+

+

-

-

+

-


Resting membrane potential1

Resting Membrane Potential

  • Know the relative ion concentrations for the neuron at rest:

  • Na+, Cl-, and Ca2+ have concentrations higher in the extracellular fluid (outside cell)

  • K+ has a higher concentration inside the cell

Na+

Cl-

-70 mV

Ca2+

K+


Na k atpase

Na+/K+ ATPase

  • Active transport of 3 Na+ out of the cell and 2 K+ into the cell powered by ATP

  • Pumps ions against gradient (by consuming energy) to maintain cellular concentrations of K+ and Na+

  • Compensates for ions leaking into/out of cell along their concentration gradient


Nernst equation

Nernst Equation

  • Equilibrium Potential (Eion) is the electrical potential of the Cell needed to generate an equilibrium state for a KNOWN concentration gradient  The electrical gradient needed to balance the concentration gradient

  • Compare this to known cell potential to predict where ions are likely to flow


Nerst equation

Nerst Equation

  • Know that K+ is found at higher concentrations inside of the cell  Concentration gradient dictates K+ would flow out of the cell

  • Calculated Equilibrium Potential for Potassium is -90 mV.

Neuron with membrane potential of -70 mV

Neuron with membrane potential of -90 mV

-

-

-

-

-

-70 mV

-90 mV

-

K+

K+

K+ will flow (leak) out of cell

Negative charges not enough to attract Positive K+to remain in the cell

No NET K+ movement

Negative charges attract Positive K+ to balance concentration gradient


Nerst equation1

Nerst Equation

  • Know that Na+ is found at higher concentrations outside of the cell  Concentration gradient dictates Na+ would flow into the cell

  • Calculated Equilibrium Potential for Na+ is +60 mV.

Neuron with membrane potential of -70 mV

Neuron with membrane potential of +60 mV

-

+

+

-

Na+

Na+

+

-70 mV

+60 mV

+

+

Na+ will leak into the cell

Negative charges not enough to repel Positive Na+to prevent movement into cell

No NET Na+ movement

Positive charges repel Positive Na+ to balance concentration gradient


Resting membrane potential ion permeability

Resting Membrane Potential & Ion Permeability

  • The relative permeability of these ions dictate how important its contribution to the resting membrane potential is

  • Ions that can move more easily through the membrane contribute greater to the RMP

  • RMP can be calculated using the Goldman Equation which takes into account the relative permeability of ions

  • Permeability can be increased by:

    1)opening gated protein channels for transport

    2) increasing the # of transport proteins


Gated channels

Gated Channels

Stretch

+

+

+ +

Channel Closed

Channel Open

Channel Closed

Channel Open

Channel Closed

Channel Open

Voltage Gated

- Respond to membrane potential changes

- Involved in initiation and conduction of electrical signals

Chemically Gated

- Respond to ligand binding (neurotransmitters, neuromodulators)

- “most important” for neurons (located in synapses)

Mechanically Gated

- Respond to physical forces

- Found in Sensory neurons


Changes in membrane potential

Changes in Membrane Potential

Repolarizationis any change in membrane potential which returns it to the Resting Membrane Potential


Graded action potentials

Graded & Action Potentials


Action potential

Action Potential

3

4

2

0

-55 mV

1

6

-70 mV

5


Action potential voltage gates

Action Potential-Voltage Gates

Na+

+

+

+

Activation Gate

Inactivation Gate

Sodium (Na+) Channel with Activation Gate (opens at -55 mV), and Inactivation Gate (voltage activated but time delayed)


Action potential voltage gates1

Action Potential-Voltage Gates

+

+

K+

Potassium (K+) Channel with Voltage Gate which opens later than Na+ channels (fully open at +30 mV)


Action potential1

Action Potential

0

MP = Less than -55 mV

+

+

1

MP = -55 mV

+

+


Action potential2

Action Potential

Na+

2

+

MP = Between -55 mV and +30 mV

+

3 &4

+

+

MP = +30 mV to -70 mV

K+


Action potential3

Action Potential

ABSOLUTE REFRACTORY

5

+

MP = Less than -70 mV

+

K+

5.5

RELATIVE REFRACTORY

+

MP = Less than -70 mV

+

K+


Refractory periods

Refractory Periods

  • Set directionality of Signal  cannot activate membrane regions which have recently fired

Na+

+

+

+

Na+

Na+

Na+


Action potential4

Action Potential


Action potential5

Action Potential


Synapses

Synapses

  • Electrical Synapses Gap junctions connect 2 cellss allowing direct electrical signalling

    - CNS; between 2 neurons, or neuron and glial cell

    - Nervous system development and transmission in adult brain

Action Potential Depolarization wave

Action Potential Depolarization wave


Chemical synapse

Chemical Synapse

Synaptic Cleft

Presynaptic cell

Postsynaptic cell

Action Potential Depolarization wave

Ions

Neurotransmitter Receptors can either open ion channel directly, or cause another (long lasting) signal cascade  coupled to G proteins etc

AP causes Ca+2 entry  vesicles release neurotransmitter

Ca2+


Types of neurotransmitters

Types of Neurotransmitters


Types of neurotransmitters1

Types of Neurotransmitters


Peripheral nervous system

Peripheral Nervous System


Key concepts

CNS

Somatic neuron Always excitatory

ACh

Nicotinic ACh receptors

Muscle Cell


Key concepts

CNS

Parasympathetic 2 Neuron chain

Sympathetic 2 Neuron Chain

Swollen Terminals Varicosity; stores a lot of neurotransmitter

Ganglion

Target Cell

Target Cell


G proteins ion channels

G Proteins & Ion Channels

IONS

e.g. Nicotinic cholinergic receptors

1 molecule of neurotransmitter opens 1 ion channel


G proteins ion channels1

G Proteins & Ion Channels

e.g. Adrenergic receptors

1 molecule of neurotransmitter can have many effects

G Protein Coupled Receptor

G Protein Coupled Receptor

G Protein Trimer

Open Ion Channels

Activate other proteins

Increase cAMP levels


Adrenergic receptors

Adrenergic Receptors


Cholinergic receptors

Cholinergic Receptors


Muscles

Muscles

  • Tissues specialized to convert biochemical reactions into mechanical work

  • Generate force, motion, & heat

  • Skeletal attached to skeleton, responsible for movement; has striations

  • Smooth  internal organs; influences movement of materials through body  no striations

  • Cardiac  Heart muscles; pumps blood; has striations


Skeletal muscles

Skeletal Muscles

  • Attach to bones via tendons at 2 points;

    - Origin at “least” moveable part of body

    -Insertion at “most” moveable part of body

  • Flexor Muscles contraction brings bones closer together

  • Extensor Muscles  contractions moves bones away from another

  • Flexor & Extensor are antagonistic pairs


Muscle structure

Muscle Structure

Epimysium- outer connective tissue

Perimysium- contains Nerves & blood vessels surround fasicles

Fascicles- Bundles of individual Muscle Fiberseach wrapped in a connective tissue sheath (Endomysium)


Muscle fibres

Muscle Fibres

  • Muscle Fibers = Muscle Cells

  • Contain mostly Myofibrils Functional unit of muscle

  • Energy from mitochondria (oxidative phosphorylation  ATP synthesis) and glycogen granules (glucose storage)

  • Cell membrane  Sarcolemma

    Cytoplamsm  Sarcoplasm

    Modified Endoplasmic Reticulum  Sarcoplasmic Reticulum  Sequester Ca2+ for rapid release into cell


Muscle fibres proteins

Muscle Fibres- Proteins


Myofibril structure

Myofibril Structure

Sarcomere

A Band

Half of I Band

Half of I Band

H Zone

Z Disk

M Line

Tintin

Thin Filament-Actin, troponin, tropomyosin

Myosin Thick Filament


Myofibril structure1

Myofibril Structure

Contraction: Thick Filaments remain same size, but thin filaments have slid closer to M line Z Discs closer together


Sliding filament theory

Sliding Filament Theory

F-Actin

1

2

3

4

5

6

1

2

3

4

5

6

Myosin Head

ATP

Step 1:

Crossbridge 45°

Myosin tightly bound

Step 2:

ATP binds to myosin head; Myosin dissociates from actin


Sliding filament theory1

Sliding Filament Theory

1

2

3

4

5

6

1

2

3

4

5

6

ADP

Pi

ADP

Pi

Step 3:

ATP Hydrolyzes to ADP + Pi

Step 4:

Myosin Head rotates, binds weakly to new actin molecule


Sliding filament theory2

Sliding Filament Theory

1

2

3

4

5

6

1

2

3

4

5

6

ADP

ADP

Pi

Step 5:

Pi is released; Myosin head rotates 45° dragging actin filament with it; POWER STROKE; Still weakly bound

Step 6:

ADP dissociates from myosin Tight binding of Myosin to Actin


Sliding filament theory3

Sliding Filament Theory

  • Overall

1

2

3

4

5

6

Myosin has not moved;

Thin Filament (actin) has

BEFORE

1

2

3

4

5

6

AFTER


Regulation of contraction

Regulation of Contraction

Troponin- 3 Subunits

Relaxed Muscles have myosin heads mainly in step 4

Tropomyosin position allows for weak binding of myosin to actin, but prohibits the ability to perform the “Power Stroke”

1

2

3

4

5

6

ADP

Pi

Tropomyosin


Regulation of contraction1

Regulation of Contraction

Troponin- 3 Subunits

Contracting Muscles troponin C subunit binds to Ca2+ which shifts the tropomysosin position allowing the myosin head to carry out the power stroke & bind tightly to actin

1

2

3

4

5

6

Calcium ; Ca2+

ADP

Tropomyosin


Excitation contraction coupling

Excitation Contraction Coupling

Cholinergic ReceptorsNa+/ K+ channels

T Tubule

Ryanodine Receptor

Sarcoplasmic Reticulum

+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Dihydropyridine Receptor (DHP)


Excitation contraction coupling1

Excitation Contraction Coupling

+

Ca2+

ACh

Ca2+

Ca2+

Na+

K+

Ca2+

Ca2+

Na+

Na+

Ca2+

Ca2+

Na+

Na+


Excitation contraction coupling2

Excitation Contraction Coupling

  • Ca2+ is pumped back into the SR by Ca2+-ATPase How fast calcium is removed dictates how fast muscle relaxes

  • Twitch  Single contraction-relaxation cycle

    -Dependant on ATPase rate and Ca2+ removal rate


Muscle energy

Muscle Energy

  • ATP Needed Myosin:Actin Interaction, ion pumps (Na+, K+, Ca2+)

  • ATP generated from glycolysis (fast, 2 ATP, produces lactic acid), or oxidative phosphorylation (slow, 30 ATP, produces CO2)

  • Creatine Phosphate can regenerate ATP from ADP (CreatinePhosphokinase) to maintain consistent ATP levels


Muscle energy and exercise

Muscle Energy and Exercise

  • Oxygen Debt Not enough O2 for oxidative phosphorylation, therefore use glycolysis by degrading glycogen stores

  • Glycolysis produces pyruvate lactic acid which must be detoxified by liver after exercise ceases & oxygen is available


Muscle fibre classification

Muscle Fibre Classification


Motor unit

Motor Unit

  • Composed of a single motor neuron and all the fibres that it controls (can be branched multiple times)

  • All muscle fibres in Motor Unit are the same type (e.g. all slow twitch)

  • # of muscle fibres associated with a neuron determines if it is “fine” control (few) or “coarse” (many muscle fibres)


Motor unit1

Motor Unit

Slow Oxidative

Slow Oxidative

Fast Glycolytic

Slow Oxidative


Muscle contraction

Muscle Contraction

  • Tension determined by sarcomere length at contraction start

Too Little Overlap Little Force


Muscle contraction1

Muscle Contraction

Too Much Overlap Little Force (Actin Filaments hit each other)


Muscle contraction2

Muscle Contraction

Even More Overlap Very Little Force (Thick Filaments hit z Disk)


Summation tetanus

Summation & Tetanus

  • Summation Rapid stimulation means no time for muscles to relax (still contracted) before muscle contracts again. This generates even more force than one action potential alone

  • Tetanus  Maximum Force of contraction (as strong as you can be)

    Incomplete  Max force, but muscle relaxes a bit between action potentials

    Complete Muscles don’t relax


Physics for bio students

Physics!......for bio students

  • Muscles & bones work like levers (rigid part) and fulcrums (pivot point)

How much force required to keep weight stationary?

Torque Up = Torque Down

Force1 X Distance1 = Force2 X Distance2

F x 5 cm = 10 kg x 25 cm

F = (10 kg x 25 cm) / 5 cm

F = 50 kg

10 kg

5 cm

25 cm


Smoooooooth muscle

Smoooooooth Muscle

Smoooothies are digested, where smooth muscles are involved as intestines, and bladder


Smoooooooth muscle cells

Smoooooooth Muscle Cells

  • 1) Single unit  gap junctions connect muscle fibres so no need to stimulate all of them (signal transduction through gap junctions)

    • Intestine, Blood Vessels

      2) Multi Unit  Each muscle fibre innervated

    • Iris & cilary body of eye, some reproductive organs

      Uterus normally multi unit but becomes single unit

      at birth


Smoooooth muscle cells key features

Smoooooth Muscle Cells: Key Features


Smooooth muscle contraction

Smooooth Muscle Contraction

Ca2+ Channels

SR/caveolae

Calmodulin

Myosin Light Chain Kinase

Voltage Gated

CaM

MLCK

Ca2+

Pi

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Stretch Activated

Ca2+

Ca2+

Myosin- Inactive

Chem. Gated


Smooooth muscle contraction1

Smooooth Muscle Contraction

Ca2+

Ca2+

Ca2+

ACTIVATES!!!!

MLCK!!!

Phosphorylates

Ca2+

Ca2+

ATP  ADP

Ca2+

CaM

Ca2+

Myosin- Active

+

Ca2+

Pi

Ca2+

Ca2+

Ca2+

Ca2+


Smoooooth muscle relaxation

Smoooooth Muscle Relaxation

  • Ca2+ removed from cytosol

    • Ca2+ ATPase, Ca2+ - Na+ antiport

  • Whats the result of this?

  • Ca2+ unbinds from CaM, MLCK inactivated, Myosin dephosphorylated (myosin light chain phosphatase)

  • Leads to Latch State


Cardiac muscle

Cardiac Muscle

<3


3 cardiac muscle

<3 Cardiac Muscle

  • Striated  therefore organised into Sarcomeres

  • Single Nucleus per cell

  • Lots of mitochondria  oxidative phosphorylation

  • Large, branched t-tubules  fast signal transduction

  • Cells joined by intercalated discs, & desmosomes  force transmission aids in contraction


Autorhythmic pacemaker cells

Autorhythmic/Pacemaker cells

  • Initiate Heartbeat (no need for nerves to control it)

  • ~1% of myocardial cells

  • Use gap junctions to conduct electric signal to other cardiac cells


Myocardial contraction

Myocardial Contraction

  • Similar to skeletal muscle contraction

Action Potential from neighbouring cells initially started by pacemaker cells

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Ca2+

Binds to Troponin

Ca2+

Ca2+

Ca2+


Myocardial contraction is graded

Myocardial Contraction is Graded

  • Force is proportional to # of active crossbridges

  • # of active crossbirdges depends on [Ca2+]

  • Force also proportional to length of muscle fibre


Factors affecting contraction force

Factors Affecting Contraction Force


Cardiac action potentials

Cardiac Action Potentials

2

3

1

4


Cadiac action potentials

Cadiac Action Potentials

1- Na+ channels open (depolarization)

2- Na+ channels Close, K+ channels open (repolarization, but brief)

3- Ca2+ channels open, some K+ channels close (plateau to prevent tetanus)

4- Ca2+ channels close, K+ channels open


Cardiovascular system

Cardiovascular System

  • Cardiovascular System  Heart, blood, and blood vessels

  • Multicellular organisms <3 the Cardiovascular System for Nutrient and Waste exchange

  • Transports nutrients, water, gas (O2, CO2), wastes, hormones, heat,


Cardiovascular system overview

Cardiovascular System Overview

Highest Pressure

Lowest Pressure

Aorta

VenaeCavae

Capillaries

Artery

Vein

Nutrients

Waste


Heart is 2 pumps

Heart is 2 Pumps

  • Pump #1

    Blood leaves heart into lungs, red blood cells bind to oxygen

     Small capillaries for fast O2 exchange, increased resistance

  • Pump #2

     Blood leaves heart to rest of the body

     Small capillaries for fast O2 exchange, increased resistance


External heart structure

External Heart Structure

Pericardium

Coronary Arteries  Supply oxygen for the heart itself

Fluid


Internal heart structure

Internal Heart Structure

Vena Cava

Right Atrium

Left Atrium

Bicuspid AV Valve

Tricuspid AV Valve

Lun

gs

Right Ventricle

Left Ventricle

ChordaeTendinae

Aortic Semilunar Valve

Pulmonary Semilunar Valve


Heart contraction

Heart Contraction

  • Autorhythmic/pacemaker cells in sinoatrial node (top of right atrium)

  • Spontaneously generate action potentials which signal contraction for the whole heart

SA


Pacemaker potentials

Pacemaker Potentials

Ca2+ channels, K+ channels open

K+ Leaves the cell

Many Ca2+ channels open

Ca2+ channels begin to open

Open If Channels – K+ moves out, Na+ moves in

-60 mV


Regulation of heart rate

Regulation of Heart Rate


Pathway of conduction

Pathway of Conduction

1)Pacemaker Cells in SA node generate Action Potential  spreads to atrial cells via gap junctions

2) Internodal Pathways spread signal to AV node (AV junction is only place where current can pass to ventricle)

3) Bundle of His/ AV Bundle fibres transmit signal to bottom (apex) of ventricles (contraction starts at bottom)

4) Purkinje Fibres move signal upwards through ventricles

SA

AV


Disorders

Disorders

  • Arrhythmia  non-SA heart cells act as pacemaker, SA node cells develop abnormal rate, conduction pathway is interrupted (signal not received in right order/time)

  • Bradycardia  slow heartbeat

  • Tachycardia  Fast heartbeat

  • Ventricular Fibrillation  Disorganized contraction, no blood pumped

  • Atrial Fibrillation Disorganized contraction, blood not pumped effectively  blood pools/clots


Key concepts

ECG

  • ECG uses electrodes on skin, need 3 for Einthoven’s Triangle

+


Key concepts

ECG

QRS complex: Ventricular Depolarization

P-Wave: Atrial Depolarization

T-Wave: Ventricular Repolarization


Key concepts

ECG

ECG

P-R Segment: Atrial Contraction

S-T Segment: Ventricular Contraction


Ecg info gained

ECG Info Gained


Cardiac cycle aka heart beat

Cardiac Cycle AKA Heart Beat

  • Systole Phase – Contraction of <3

  • Diastole Phase – Relaxation of <3


Cardiac cycle

Cardiac Cycle

Atria and Ventricle Relaxed

AV valves open

Blood enters ventricles passively

Atria Contracts

Blood enters Ventricle

Semiluminar (SL) valves open, AV valves closed (Lub)

Ventricular relaxation  SL, AV valves closed (dub)

Ventricles Contract (isovolume)

SL and AV valves closed

Ventricular Ejection  SL valves open


Cardiac cycle1

Cardiac Cycle

  • End Diastolic Volume (EDV)  Maximum volume (amount of blood) in ventricle

  • End Systolic Volume (ESV) minimum volume of ventricle


Cardiac output

Cardiac Output

Cardiac Output = Heart rate x stoke volume

Cardiac Output = Heart rate x [EDV – ESV]

Parasym. Stimulation (ACh)  Decrease contraction of heart (lower stroke volume) by decreasing Ca2+

Sym. Stimulation (Norepinephrine)  Increase contraction of heart by increasing Ca2+

Epinephrine  Increase contraction of heart by increasing Ca2+

Frank-Starling Law  Stroke volume is larger with greater EDV  more myosin-binding sites on thin filament, Ca2+ enters cells more easily


Blood vessels

Blood Vessels

  • Endothelial cells (all vessels)

  • Vascular Smooth muscle  Regulates diameter (vasoconstriction vs. vasodilator)

  • Elastic Connective Tissue

  • Fibrous Connective Tissue

Lumen


Blood vessels1

Blood Vessels


Blood flow

Blood Flow


Blood flow1

Blood Flow

  • Flow is proportional to pressure difference (ΔP)

    -Kinetic component of pressure (in direction of flow)

    -Static component of pressure (hydrostatics on walls of vessel)

  • MyogenicAutoregulation- Stretch receptors in blood vessels cause constriction

  • Paracrine Hormones – Endothelium cells affect cells around them

  • Nerves of Sym. Nervous System:

    NE  Bind α receptors for constriction

    Epinephrine  Bind α receptors to reinforce constriction

  • Hormone Signals  Epinephrine binds β2 receptors, vasodilation, smooth muscle of heart, live, muscles


Pressure

Pressure

  • Pressure Increases with decrease volume (the squeeze)

  • Pressure decreases with friction (also known as resistance)

  • R = 8Lη/πr4 Large impact of Radius, since L and η are normally constant

  • Flow is inversely proportional to Resistance (proportional to r4)


Blood pressure

Blood Pressure

  • Systole Pressure  Highest Arterial Pressure (when ventricles contract)

  • Diastole Pressure  Lowest Arterial Pressure (when ventricles relax)

  • Sphygmomanometry Cuff inflates to cut off blood flow, then deflated

    Cuff Pressure = Systolic pressure blood will flow, but will be turbulent (Korotkoff Sound)

    Cuff pressure lowered still, when cuff pressure = diastolic pressure, no sound/turbulence


Mean arterial pressure

Mean Arterial Pressure

  • Mean Arterial Pressure = Diastolic + 1/3 (systolic – diastolic)

  • Affected by cardiac output, blood volume, peripheral resistance (radius change of blood vessel)


Cns regulation of blood pressure

CNS regulation of Blood Pressure

  • Baroreceptors stretch receptors in carotid artery (brain BP) and aorta (body BP)

  • High BP- Stretch receptors increase in firing rate  Action potentials to Medulla of CNS  efferent pathway decreases sympathetic/increases parasym. output  vasodilation, decrease heart contraction force, lowered heart rate, decreased cardiac output  DECREASE in BP


Cns regulation of blood pressure1

CNS regulation of Blood Pressure

  • Low BP- Stretch receptors Decrease in firing rate  Fewer Action potentials to Medulla of CNS  efferent pathway increases sympathetic/decreases parasym. output  vasoconstriction, increase heart contraction force, increased heart rate, increased cardiac output  INCREASE in BP


Blood

Blood


Haemoglobin

Haemoglobin

  • Protein that binds O2, made of 4 chains (globins),

  • Fetal form binds O2 released by mother

  • Iron (Fe) necessary for O2 binding (70% of iron in body)

  • Sigmoidal Curve of O2 binding


Key concepts

% bound heme groups

O2 Concentration


Regulation of heme

Regulation of Heme


Haematopoiesis

Haematopoiesis

  • Blood cells produced in bone marrow from pluripotenthaemapoetic stem cells

  • Uncommitted stem cells  many fates possible

  • Progenitor Cells  Committed to 1 or 2 cell fates


Cytokines

Cytokines

  • Guide cell fate in haematopoiesis

  • Small peptide signals

  • E.g. Colony-stimulating factors

    Interleukins- released by 1 WBC to act on another WBC

    Thrombopoeitin –regulates formation of megakaryocytes

    Erythropoietin- RBC development


Stem cell fates

Stem Cell Fates


Haemostasis

Haemostasis

  • 1) Vasoconstriction  Decrease blood flow

  • 2) Platelet plug  Platelets stick to exposed collagen; cytokines promote platelet formation; activated platelets stick together to slow blood flow and begin clotting

  • 3) Factor XII, collagen, tissue factor III activate plasma proteins  thrombin activated and cleaves fibrinogen to fibrin and activates factor XIII  fibrin cross-linked to long fibres  clot forms

  • Healing has plasmin dissolving clot (fibrinolysis)

    Thrombus is extensive clotting that blocks blood vessel


Respiratory system

Respiratory System

  • Four functions

  • Gas exchange between blood & atmosphere

  • Homeostasis of blood pH

  • Protection from foreign particles/pathogens

  • Vocalization


Respiratory system structures

Respiratory System-Structures


Gas laws

Gas Laws

  • Partial pressure is the amount of total pressure of a mixture of gasses that is produced by one gas in the mixture:

    Pgas=(Ptotal)(% of gas in mixture)

  • Amount of gas (O2, CO2) that can dissolve in a liquid (blood) depends on partial pressure of the gas and its relative solubility


Lungs

Lungs

  • Lung Volume depends on transpulmonary pressure (ΔP between alveolar pressure and intrapleural pressure) and elasticity of lungs (how easily they inflate)

  • Boyles Law: P1V1 = P2V2


Respiratory cycle

Respiratory Cycle


Lung compliance and elastance

Lung Compliance and Elastance

  • Compliance: Magnitude of lung volume change for given pressure change

  • Lower Compliance  Harder to Expand Lungs

    -Fibrotic Lung Disease  Scar Tissue decreases lung compliance

    -Low Surfactant Decreases Compliance Surfactant produced by type II aveolar cells required to lower lung surface tension to make it easier to expand


Lung elastance

Lung Elastance

  • Elastance: Degree to which the lung will return to its original volume

  • Low elastance Expiration must be active

    -Emphysema: Elastin fibres destroyed, low elastance, breathing out must be forced


Airway resistance

Airway Resistance

  • Resistance depends on airway radius (R = 8Lη/πr4)  can change bronchiole diameter with nervous system (parasym.)/hormones to alter pressure

  • CO2, epinephrine (β2 receptors) can cause bronchodilation

  • Histamine, parasym. nerves cause bronchoconstriction


Pulmonary function

Pulmonary Function


Efficiency of breathing

Efficiency of Breathing


Gas transport

Gas Transport

  • Oxygen transported bound to haemoglobin

  • CO2 transport through either binding to proteins (N-terminal end) or conversion to carbonic acid (H2CO3) by carbonic anhydrase (lowers blood pH) HCO3- exchanged with Cl- to transport molecules out of RBC until equilibrium shifts in lungs

    CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+


Gas transport1

Gas Transport

In Alveola

In Capillaries

RBC

O2

O2

HCO3-

CO2

Cl-

CO2

Cl-

HCO3-

Plasma


Ventilation control

Ventilation Control

  • Contraction of respiratory muscles initiated in medulla by Central Pattern Generator

    • Dorsal Respiratory Group (DRG)  Inspiratory neurons  control externalintercostal muscles, diaphragm

    • Ventral Respiratory Group (VRG)  Active Expiration Neurons  Control internal intercostal muscles, and abdominal muscles


Chemo mechanoreceptor regulation

Chemo-/Mechanoreceptor Regulation


Immune system

Immune System

  • 1) Protect body fro microbes, parasites, allergens

  • 2) Remove dead, damaged tissue

  • 3)Recognize and remove abnormal cells


Immune system diseases

Immune System Diseases

  • Autoimmunity  Immune system attacks the body’s own cells

  • Overactive Responses  Allergies

  • Lack of response  immunodeficiency


Immune system organs tissues

Immune System Organs/Tissues

  • Lymphoid Organs and Lymph  carry lymph (Clear Fluid) which lymphocytes can travel through

  • Lymphocytes = leukocytes that can access lymph system

  • Lymph nodes in various places around body


Lymphoid organs

Lymphoid Organs


Leukocytes

Leukocytes


Leukocytes1

Leukocytes


Haematopoesis

Haematopoesis


Immune response

Immune Response

  • Detect Foreign Substance

  • Communicate with Immune Cells

  • Recruit & coordinate response

  • Destruction of invader

  • Antibodies  molecules that bind antigens

  • Cytokines  Molecules that differentiate leukocytes


Innate immune response

Innate Immune Response

  • Rapid and Non-specific

  • Always present; clear 95% of all pathogens

  • Includes physical (skin), and chemical (mucus) barriers, as well as patrolling non-specific leukocytes

  • Innate Leukocytes mostly phagocytes (macrophages, neutrophils)  ingest invaders, secret molecules to attract other immune cells

  • Phagocytes can recognized foreign particles, or particles tagged (opsonized) by blood proteins (opsonin)


Innate immune response1

Innate Immune Response

  • Natural Killer Cells  Lymphocytes, can cause apoptosis in infected cells (viruses), or tumour cells, produce:

    • Interferons (Cytokines)  α, β interferon prevent viral replication

       γ interferon recruits macrophages, etc


Inflammation

Inflammation

  • Part of Innate Immune Response

  • Swelling attracts immune cells, causes fever, prevents pathogen spreading (barrier  quarantine)

  • Caused by Cytokines: Interleukin-1 acts on endothelial cells of blood vessel, liver cells (damage control blood proteins), induces fever, stimulate other cytokine production


Complement proteins

Complement Proteins

  • Opsonins, chemotaxins, Membrane Attack Complex (MAC)

  • MAC proteins makes holes in pathogen membrane to introduce ions  osmosis caused cell to swell/lyse


Acquired immunity

Acquired Immunity

  • Antigen specific recognize specific pathogens

  • T, B-cells are mostly specific to certain antigen, which when bound causes clonal replication (many cells that target the specific pathogen) that are either effector cells (destroy pathogen) or memory cells (remember pathogen)


B cells

B Cells

  • B cells: Develop in bone marrow (humans) or Bursa of Fabricius (chickens); Produce Antibodies (immunoglobins)

  • Activated B Cells become plasma cells (short lived) produce a LOT of antibodies

  • Primary response  naive cells become specialized for new antigen; response is slow and low Ab concentration produced

  • Secondary response  Rapid, many antibodies produced, mediated by memory cells


Antibodies

Antibodies


Antibodies1

Antibodies

Ag Binding

-Make up 20% of proteins in blood; good against extracellular pathogens

Fab Region

Fc Region-Determines Ab class; elicit response


Antibody functions

Antibody Functions

  • 1)Act as opsonins

  • 2) Cause aggregation of pathogen

  • 3) Neutralize toxins

  • 4) Activate complement

  • 5) Activate B cells; have Ab that act as receptors

  • 6) Activate NK cells; Fc receptors

  • 7) Activate Mast cells; Fc receptors


T cells

T Cells

  • T Cells: Mature in thymus; bind Ag on Major Histocompatibility Complex

  • Class I MHC Peptides are presented in MHC to CytotoxicTc cells - Tc cells kill cells infected with viruses since they present viral proteins

  • Class II MHC present on surface of specialized immune cells (APCs); bound by Helper T cells


T cells1

T Cells

  • Cytotoxic T Cells (Tc) Kills cells expressing certain antigen (present on Class I MHC)

Infected Cell

T Cell

Ag

MHC


T cells2

T Cells

  • Helper T Cells; bind antigens on MHC class II on APCs, secrete cytokines to activate B cells and other T cells

Infected Cell

T Cell

Ag

MHC


Extracellular bacteria

Extracellular Bacteria

  • 1) Complement activates by bacterial cell wall components  chemotaxins attract leukocytes, MAC lyse bacteria, opsonize bacteria

  • 2) Haemostasis if blood vessel breaks (swelling)

  • 3)Cytokines produced by complement/phagocytes, activated lymphocytes present antigens

  • 4) TH Cells activate B cells (cytokines)

  • 5) B cells produce Ab


Viruses

Viruses

  • 1) Extracellular phase Abopsonize, Phagocytes neutralize – prevent entry into cells

  • 2) Infected Host cells produce Interferon β; macrophage produce interferon α  Antiviral state

  • 3) Cytokines secreted by host cells activate NK and Tc cells

  • 4)TcCells recognize infected cells via MHC class I and kill it


Allergic response

Allergic Response

  • Inflammatory response caused by antigens

  • -Atopic individuals have excessive response which causes more harm than antigen

  • Immediate Hypersensitivity Ab mediated

  • Delayed Type Hypersensitivity  T cells and Macrophage mediated

  • Sensitization first (Ag ingested by APC, activates TH cells, and B cells  memory cells

  • Re-Exposure: IgE on masts cells detects allergen Mast Cells degranulate Histamines, cytokines  inflammatory reaction


Practice questions

Practice Questions

  • The teleological approach to physiology:

    a) Explains “how” a process occurs

    b) Examines how an organism maintains a stable internal environment

    c) Describes the “Function” of a system

    d) Describes the “Process” of a system


Practice questions1

Practice Questions

  • Which of the following is NOT an example of homeostatis?

    a) Maintaining a blood pH level of ~7

    b) Keeping blood [Na+] within a normal range

    c) A snakes body temperature matching that of its environment

    d) Negative feedback controlling blood pressure

    e) All of the above are homeostatic


Practice questions2

Practice Questions

  • Which of the following are types of connective tissue?

    a) Adipose

    b) Bone

    c) Blood

    d) Skeletal muscle

    e) Loose, elastic


Practice questions3

Practice Questions

  • _______, and ______ are associated with local communication, while ______ are a component of long distance communication

    a) Paracrines, Autocrines, Acetylcholine

    b) Paracrines, Autocrines, Endocrines

    c) Neurotransmitters, Connexons, Endocrines

    d) Endocrines, Paracrines, Autocrines

    e) None of the Above


Practice questions4

Practice Questions

  • The type of signalling molecule determines the response that occurs in the cell

    a) True

    b) False


Practice questions5

Practice Questions

  • Which of the following pairs are analogous in the CNS and PNS

    a)Nuclei; Ganglia

    b) Tracts; Nerves

    c) Oligodendria; Schwann cells

    d) All of the Above

    e) None of the Above


Practice questions6

Practice Questions

  • Efferent Neurons

    a) Are a part of the sympathetic nervous system

    b) Are the main component of the CNS

    c) Carry information to the CNS

    d) Have cell bodies within the CNS

    e) Include auditory nerve cells which sense sound


Practice questions7

Practice Questions

  • Which is NOT true of Glial Cells

    a) They outnumber neurons

    b) They do not carry electrical signals

    c) They Insulate neurons for better signal conduction

    d) They can remove dead/foreign cells

    e) All of the above are true


Practice questions8

Practice Questions

  • A new element is discovered at high concentrations in the extracellular fluid of neural tissue in an ionic form. The ion, J-2 has a negative charge and the cell membrane is completely impermeable to this ion. Which of the following are true statements:

    a) The ion has a significant impact on the resting membrane potential of neurons

    b) If J-2 were allowed to enter the cell it would be hyperpolarizing

    c) If J-2 were allowed to enter the cell as part of a graded potential, it would help trigger an Action Potential

    d) Osmotically speaking, the concentration gradient forces the ion out of the neuron.

    e) None of the above


Practice questions9

Practice Questions

  • Which of the following is found at relatively low concentrations in the resting neural cell

    a) K+

    b) Phosphate

    c) Ca2+

    d)Na+

    e) B, C, D

    f) C, D


Practice questions10

Practice Questions

  • A Positive ion is calculated to have an equilibrium potential of -20 mV. The ion will have a tendency to leak out of the cell:

    a) At resting membrane potential

    b) At the peak of an action potential

    c) During the refractory period

    d) None of the above


Practice questions11

Practice Questions

  • Graded Potentials

    a) Always cause depolarization

    b) Can be summer temporally and spatially

    c) Can travel long distances

    d) Can only be caused by Na+ transport

    e) None of the above


Practice questions12

Practice Questions

  • During the rising (depolarization) phase of an action potential

    a) The sodium channel is open

    b) The Na+/K+ATPase is inactive

    c) The cell is undergoing a positive feedback loop

    d) The Potassium channel is pumping K+ into the cell

    e) A and C


Practice questions13

Practice Questions

  • What determines the threshold potential of a neuron?

    a) The properties of the voltage gated potassium channel

    b) The resting membrane potential

    c) The properties of the voltage gated sodium channel

    d) Excitatory Post Synaptic Potentials

    e) None of the above


Practice questions14

Practice Questions

  • The absolute refractory period:

    a) Last ~ 1 msec

    b) Prevents an action potential from occuring unless a suprathreshold stimulus is applied

    c) Occurs because the potassium channel is closed

    d) Ensures action potentials move in one direction

    e) A and D


Practice questions15

Practice Questions

  • Which of the following is NOT a method to reduce resistance in nerves?

    a) Lowering the surface area:volume ratio of a nerve

    b) Having giant axons

    c) Wrap cells in myelin sheath

    d) Increasing ionic leaking through the cell membrane


Practice questions16

Practice Questions

  • When Ca2+ channels in the axon terminal open

    a) The axon terminal was recently depolarized by an action potential

    b) Neurotransmitter will be released

    c) Calcium flows out of the cell into the synaptic cleft

    d) A and B

    e) All of the above


Practice questions17

Practice Questions

  • Nitric Oxide

    a) Is a stable gas

    b) Is synthesized by Nitric Oxide Synthase

    c) Is stored in neurotransmitter vesicles

    d) Is a biogenic amine type neurotransmitter

    e) All of the above


Practice questions18

Practice Questions

  • Acetlycholine

    a) Is synthesized from acetate and choline

    b) Is degraded in the synapse by choline acetyl transferase

    c) Is released by neurons of the parasympathetic pathway, but not the sympathetic

    d) Will not bind to muscarinic receptors

    e) None of the above


Practice questions19

Practice Questions

  • Which of the following is true with regards to nicotinic receptors?

    a) They bind nicotine as an antagonist

    b) They act via ion channels

    c) They are a slow synaptic potential using G proteins

    d) They are found on tissues of the parasympathetic pathway

    e) None of the Above


Practice questions20

Practice Questions

  • Somatic neurons:

    a) Have a single neuron between the CNS and muscle fibre

    b) Each control a distinct motor unit

    c) Release ACh which binds adrenergic receptors

    d) Are afferent neurons

    e)A and B


Practice questions21

Practice Questions

  • Which is true of skeletal muscles?

    a) They can only contract

    b) They generate both motion and force

    c) They do not control the contractions of the heart

    d) They appear striated under a microscope

    e) All of the above


Practice questions22

Practice Questions

  • The role of Troponin

    a) Involves the binding of calcium ions

    b) Involves the interaction with nebulin

    c) Activates contraction in the absence of Ca+2

    d) Involves a direct interaction with ryanodine receptors

    e) None of the above


Practice questions23

Practice Questions

  • The Thin Filament is:

    a) Composed of G Actin

    b) Composed of F Actin

    c) Composed of Myosin

    d) Makes up the M Line

    e) Is the only component of the H zone


Practice questions24

Practice Questions

  • The “Power Stroke” of a myosin molecule:

    a) Involves the release of ADP

    b) Requires Ca2+ to be bound to tropomyosin

    c) Moves consecutive Z discs further apart

    d) Requires the release of inorganic phosphate


Practice questions25

Practice Questions

  • At the motor end plate:

    a) ACh is bound nicotinic andrenergic receptors

    b) K+ efflux exceeds Na+ influx when Na+/K+ channels are open

    c) Curare can block receptors

    d) DHP receptors bind ACh


Practice questions26

Practice Questions

  • Muscles can use energy from:

    a) Oxidative phosphorylation

    b) ATP

    c) Glycolysis

    d) Creatine-Phosphate

    e) All of the above


Practice questions27

Practice Questions

  • Which is true of Slow-twitch oxidative muscle fibres?

    a) They have a lower threshold for recruitment then fast-twitch glycolytic

    b) They are easily fatigued

    c) They are Red in colour

    d) The have a fast myosin ATPase

    e) A and C

    f)B and D


Practice questions28

Practice Questions

  • Isometric muscle contraction:

    a) Moves the body

    b) Does not create force

    c) Has muscle length change

    d) Has sarcomeres shorten

    e) None of the above


Practice questions29

Practice Questions

  • β1 type receptors are:

    a) Cholinergic receptors

    b) Are responsive more to norepinephrine than epinephrine

    c) Increase cAMP production when active

    d) Increase cytosolic Ca+2 levels


Practice questions30

Practice Questions

  • The cheetah is the fastest land mammal on Earth. Its muscles are easily fatigued, produce high amounts of lactic acid and use glycogen as a primary source of energy. Cheetah muscles are likely made of what type of muscle fibres?

    a) Fast Oxidative

    b) Fast Glycolytic

    c) Slow Glycolytic

    d) Slow Oxidative


Practice questions31

Practice Questions

  • A 7 kg weight is held 24 cm from the elbow. The bicep is inserted 6 cm from elbow. How much force is required to keep the weight stationary?

    a) 28 kg

    b) 25 kg

    c) 42 kg

    d) 20 kg


Practice questions32

Practice Questions

  • Writer’s Cramp:

    a) Is a result of tetanus of the muscle

    b) Can be treated with botulinum toxin

    c) Can be treated by increasing ACh levels

  • A and B

  • All of the above


Practice questions33

Practice Questions

  • Multiunit smooth muscle cells are connected via gap junctions to conduct electric signals throughout the tissue:

    a) True

    b) False


Practice questions34

Practice Questions

  • Which of the following have equivalent functions in skeletal muscles and smooth muscles?

    a) Skeletal muscle troponin/Smooth Muscle troponin

    b) Dense Bodies/Z lines

    c) T Tubules/caveolae

    d) None of the above


Practice questions35

Practice Questions

  • Myosin Light Chain Kinase:

    a) Is activated by calmodulin when CaM is not bound to Ca2+

    b) Phosphorylates the heavy chain of myosin

    c) Derives energy from ATP

    d) Dephosphorylates Myosin in low Ca2+ conditions


Practice questions36

Practice Questions

  • Which is true with regard to cardiac muscle fibres

    a) They primarily undergo glycolysis for ATP production

    b) The are no t-tubules

    c) All cells are involved in contraction

    d) Undergo “all-or-none” style contraction

    e) None of the above


Practice questions37

Practice Questions

  • Phospholamban

    a) Regulates cardiac muscle contraction

    b) Increases SR Ca2+

    c) Decreases Ca2+ ATPase activity

    d) All of the above

    e) A and B


Practice questions38

Practice Questions

2

3

  • The Above Diagram represents:

    a) Smooth muscle action potential

    b) Cadiac pacemaker action potential

    c) Cardiac muscle action potential

    d) Neuron action potential

1

4


Practice questions39

Practice Questions

2

3

  • At the point marked “3”:

    a) Ca2+ channels are open

    b) Na+ channels are open

    c) Cardiac muscles are undergoing tetanus

    d) The cells are being rapidly hyperpolarized

1

4


Practice questions40

Practice Questions

  • The cardiovascular system is responsible for:

    a) Nutrient transport

    b) Hormone transport

    c) Transport of CO2+ from tissues to environment

    d) All of the Above


Practice questions41

Practice Questions

  • The right atrium pumps blood into ____ after receiving blood from ________

    a) Left Ventricle; the lungs

    b) The pulmonary artery; pulmonary vein

    c) Right Ventricle; Pulmonary vein

    d) Right Ventricle; venaecavae


Practice questions42

Practice Questions

  • The ______ Valve(s) help prevent backflow of blood into the atrium

    a) AV

    b) Tricuspid

    c) Bicuspid

    d) All of the above


Practice questions43

Practice Questions

  • Which of the following are true

    a) Chordaetendinae prevent the semilunar valves from being pushed back into atrium

    b) Semilunar valves prevent blood from flowing backwards into the aorta

    c) AV Valves close prior to atrial contraction

    d) The closing of the semilunar valves is the “dub” sound of the heart beat


Practice questions44

Practice Questions

  • The rate of packemaker potentials, and therefore the rate of heart contraction, can be increased by:

    a)Norepinephrine from parasympathetic neurons

    b)Acetylcholine from parasympathetic neurons

    c) Increasing K+ permeability

    d) Increased levels of cytosolcAMP


Practice questions45

Practice Questions

  • i. Purkinje Fibres

  • ii. AV Node

  • iii. Bundle of His

  • iv. SA Node

  • The correct pathway of conduction for cardiac cells to contract is:

    a) i, ii, iii, iv

    b) iv, ii, i, iii

    c) iv, ii, iii, i

    d) ii, iii, iv, i


Practice questions46

Practice Questions

  • Which of these is not a cause of arrhythmia

    a) SA node developing abnormal rate

    b) Cells in ventricle acting as pacemakers

    c) Blocking conduction through the AV node

    d) Closing of the AV valves


Practice questions47

Practice Questions

  • The region marked as T corresponds to:

    a) Atrial contraction

    b) Ventricular depolarization

    c) An irregular heart beat showing blocked AV conduction

    d) Ventricular repolarization


Practice questions48

Practice Questions

  • An incompletely closed heart valve can be diagnosed by what sound?

    a) lub

    b) dub

    c) clicking

    d) Whoosh

    e) All of the above are normal sounds


Practice questions49

Practice Questions

  • In the cardiac cycle which of the following means relaxation?

    a) Systole

    b) Stroke Volume

    c) Diastole

    d) All of the above


Practice questions50

Practice Questions

  • Which of the following is the thickest blood vessel?

    a) Capillary

    b) Arteriole

    c) Venule

    d)Artery


Practice questions51

Practice Questions

  • Blood Pressure:

    a) Is commonly measured in mm Hg

    b) Allows blood flow from high pressure to low pressure

    c) Has a kinetic and static component

    d) Is affected by friction and blood viscosity

    e) All of the above


Practice questions52

Practice Questions

  • If the diastolic pressure is 80 torr, and systolic pressure is 120 torr, what is the mean arterial pressure?

    a) 100 torr

    b) 93 torr

    c) 120 torr

    d) 90 torr


Practice questions53

Practice Questions

  • In conditions of high blood pressure, baroreceptors will fire

    a) More frequently

    b) Less frequently

    c) To send signals to the peripheral nervous system

    d) To send signals to increase vasoconstriction


Practice questions54

Practice Questions

  • Which of the following is not a granulocyte?

    a) Neutrophils

    b) Monocytes

    c) Mast Cells

    d)Eosinophils


Practice questions55

Practice Questions

  • Which of the following promotes O2 binding to haemoglobin?

    a) CO

    b) High temperature

    c) Replacing normal haemoglobin with fetalhaemoglobin

    d) Low pH


Practice questions56

Practice Questions

  • Which one of the cytokine:cell fate pairs is mismatched?

    a) EPO:RBC

    b) Thromopoietin:megakaryocytes

    c) Colony Stimulating Factor:Leukocytes

    d) All of the above are correctly matched


Practice questions57

Practice Questions

  • In the haemostatis pathway, what is the correct order of activation?

    a) Plasmin, Thrombin, Factor XII, Factor XIII

    b)Factor XII, Thrombin, Factor XIII, Plasmin

    c) Factor XII, Fibrin, Thrombin, Plasmin

    d) Factor XIII, Thrombin, Factor XII, Plasmin


Practice questions58

Practice Questions

  • Which of the following is not part of the upper respiratory system?

    a) Mouth

    b) Trachea

    c) Larynx

    d) Nasal Cavity


Practice questions59

Practice Questions

  • Disruption of Type II alveolar cell activity would result in:

    a) Decreased gas exchange with blood

    b) Lowered surfactant levels

    c) Emphysema

    d) Low lung compliance

    e) B and D

    f) C and D


Practice questions60

Practice Questions

  • Pneumothorax

    a) Is a collapsed lung

    b) Results from air being expelled from pleural cavity

    c) Can be treated by increased pleural fluid pressure

    d) Can be treated with the Heimlich manoeuvre


Practice questions61

Practice Questions

  • The volume of air that can be voluntarily moved via respiration:

    a) Is equivalent to the total lung capacity

    b) Is the total lung capacity minus the residual volume

    c) Is less than the inspiratory and expiratory reserve volumes

    d) Includes air left in lungs after maximum expiration


Practice questions62

Practice Questions

  • With respect to total pulmonary ventilation and alveolar ventilation:

    a) The two are always equal

    b) Total pulmonary ventilation reflects the amount of air that can exchange gas with blood

    c) Both depend on rate and depth of breathing

    d) None of the above


Practice questions63

Practice Questions

  • The _______ Respiratory Group controls ______ neurons and the external intercostal muscles. The Ventral Respiratory Group controls _______ and the internal intercostal muscles:

    a) Dorsal; inspiratory; expiration

    b) Ventral; expiratory; the diaphragm

    c) Dorsal; inspiratory; inspiration

    d) Central; inspiratory; expiration


Practice questions64

Practice Questions

  • Eosinophils:

    a) Have dark blue staining granulocytes

    b) Have a lifespan of several days

    c) Kill parasites through degranulation

    d) Are not found in the digestive tract


Practice questions65

Practice Questions

  • Monocytes:

    a) Will become macrophages in the tissue

    b) Will degrade dead cells

    c) Are APC’s

    d) Are not granulocytes

    e) All of the above


Practice questions66

Practice Questions

  • T cells develop in the_____

    a) GALT

    b)Tonsils

    c) Thymus

    d) Bone marrow


Practice questions67

Practice Questions

  • Thrombocytes

    a) Are not “true” cells

    b) Arise from megakaryocytes

    c) Are involved in blood clotting

    d) Are found in the blood where there is no damage

    e) All of the above


Practice questions68

Practice Questions

  • Cytotoxic T cells:

    a) Are part of the innate immune response

    b) Recognize antibodies on the MHC

    c) Are lymphocytes that produce granzymes

    d)Develop in the Bursa of Fabricius

    e) Bind to MHC found only on specialized immune cells


Practice questions69

Practice Questions

  • Which of the following are components of innate immunity?

    a) Skin

    b) B cells

    c) Natural Killer Cells

    d) Humoral immunity

    e) B and C

    f)A and C


Practice questions70

Practice Questions

  • The Membrane Attack Complex

    a) Is part of innate immunity

    b) Lyses cells through digestive enzymes

    c) Is formed by leukocytes

    d) Is constructed of blood proteins

    e) A and D


Practice questions71

Practice Questions

  • The Fab region of an antibody is responsible for __________, while the ____ region is determines the class of antibody

    a) Hinge Region, light chains

    b) Antigen Binding, IgA

    c) Antigen Binding, Fc

    d) Cytokine production, Arm

    e) Allergic responses, Y unit


Practice questions72

Practice Questions

  • The Fc region of an antibody is composed of:

    a) 1 heavy chain

    b) 2 heavy chains

    c) The arms of the antibody

    d) Two light chains

    e) Two light chains and two heavy chains


Practice questions73

Practice Questions

  • Interferon is synthesized:

    a) As part of the immune response to viruses

    b) As part of the immune response to bacteria

    c) By the infected cell/natural killer cells

    d) To opsonize pathogens for phagocytosis

    e) B and D

    f) A and C


Practice questions74

Practice Questions

  • IgE molecules

    a) Are antigens

    b) Are found in secretions

    c) Mediate allergic responses

    d) Are made by B cells

    e) A and D

    f) C and D


Practice answers

Practice Answers


Practice questions75

Practice Questions

  • The teleological approach to physiology:

    a) Explains “how” a process occurs

    b) Examines how an organism maintains a stable internal environment

    c) Describes the “Function” of a system

    d) Describes the “Process” of a system


Practice questions76

Practice Questions

  • Which of the following is NOT an example of homeostatis?

    a) Maintaining a blood pH level of ~7

    b) Keeping blood [Na+] within a normal range

    c) A snakes body temperature matching that of its environment

    d) Negative feedback controlling blood pressure

    e) All of the above are homeostatic


Practice questions77

Practice Questions

  • Which of the following are types of connective tissue?

    a) Adipose

    b) Bone

    c) Blood

    d) Skeletal muscle

    e) Loose, elastic


Practice questions78

Practice Questions

  • _______, and ______ are associated with local communication, while ______ are a component of long distance communication

    a) Paracrines, Autocrines, Acetylcholine

    b) Paracrines, Autocrines, Endocrines

    c) Neurotransmitters, Connexons, Endocrines

    d) Endocrines, Paracrines, Autocrines

    e) None of the Above


Practice questions79

Practice Questions

  • The type of signalling molecule determines the response that occurs in the cell

    a) True

    b) False


Practice questions80

Practice Questions

  • Which of the following pairs are analogous in the CNS and PNS

    a)Nuclei; Ganglia

    b) Tracts; Nerves

    c) Oligodendria; Schwann cells

    d) All of the Above

    e) None of the Above


Practice questions81

Practice Questions

  • Efferent Neurons

    a) Are a part of the sympathetic nervous system

    b) Are the main component of the CNS

    c) Carry information to the CNS

    d) Have cell bodies within the CNS

    e) Include auditory nerve cells which sense sound


Practice questions82

Practice Questions

  • Which is NOT true of Glial Cells

    a) They outnumber neurons

    b) They do not carry electrical signals (they do over short distances)

    c) They Insulate neurons for better signal conduction

    d) They can remove dead/foreign cells

    e) All of the above are true


Practice questions83

Practice Questions

  • A new element is discovered at high concentrations in the extracellular fluid of neural tissue in an ionic form. The ion, J-2 has a negative charge and the cell membrane is completely impermeable to this ion. Which of the following are true statements:

    a) The ion has a significant impact on the resting membrane potential of neurons

    b) If J-2 were allowed to enter the cell it would be hyperpolarizing

    c) If J-2 were allowed to enter the cell as part of a graded potential, it would help trigger an Action Potential

    d) Osmotically speaking, the concentration gradient forces the ion out of the neuron.

    e) None of the above


Practice questions84

Practice Questions

  • Which of the following is found at relatively low concentrations in the resting neural cell

    a) K+

    b) Phosphate

    c) Ca2+

    d)Na+

    e) B, C, D

    f) C, D


Practice questions85

Practice Questions

  • A Positive ion is calculated to have an equilibrium potential of -20 mV. The ion will have a tendency to leak out of the cell:

    a) At resting membrane potential

    b) At the peak of an action potential (+30 mV is greater than -20 mV)

    c) During the refractory period

    d) None of the above


Practice questions86

Practice Questions

  • Graded Potentials

    a) Always cause depolarization

    b) Can be summed temporally and spatially

    c) Can travel long distances

    d) Can only be caused by Na+ transport

    e) None of the above


Practice questions87

Practice Questions

  • During the rising (depolarization) phase of an action potential

    a) The sodium channel is open

    b) The Na+/K+ATPase is inactive

    c) The cell is undergoing a positive feedback loop

    d) The Potassium channel is pumping K+ into the cell

    e) A and C


Practice questions88

Practice Questions

  • What determines the threshold potential of a neuron?

    a) The properties of the voltage gated potassium channel

    b) The resting membrane potential

    c) The properties of the voltage gated sodium channel

    d) Excitatory Post Synaptic Potentials

    e) None of the above


Practice questions89

Practice Questions

  • The absolute refractory period:

    a) Last ~ 1 msec

    b) Prevents an action potential from occuring unless a suprathreshold stimulus is applied

    c) Occurs because the potassium channel is closed

    d) Ensures action potentials move in one direction

    e) A and D


Practice questions90

Practice Questions

  • Which of the following is NOT a method to reduce resistance in nerves?

    a) Lowering the surface area:volume ratio of a nerve

    b) Having giant axons

    c) Wrap cells in myelin sheath

    d) Increasing ionic leaking through the cell membrane


Practice questions91

Practice Questions

  • When Ca2+ channels in the axon terminal open

    a) The axon terminal was recently depolarized by an action potential

    b) Neurotransmitter will be released

    c) Calcium flows out of the cell into the synaptic cleft

    d) A and B

    e) All of the above


Practice questions92

Practice Questions

  • Nitric Oxide

    a) Is a stable gas

    b) Is synthesized by Nitric Oxide Synthase

    c) Is stored in neurotransmitter vesicles

    d) Is a biogenic amine type neurotransmitter

    e) All of the above


Practice questions93

Practice Questions

  • Acetylcholine

    a) Is synthesized from acetate and choline

    b) Is degraded in the synapse by choline acetyl transferase

    c) Is released by neurons of the parasympathetic pathway, but not the sympathetic

    d) Will not bind to muscarinic receptors

    e) None of the above


Practice questions94

Practice Questions

  • Which of the following is true with regards to nicotinic receptors?

    a) They bind nicotine as an antagonist

    b) They act via ion channels

    c) They are a slow synaptic potential using G proteins

    d) They are found on tissues of the parasympathetic pathway

    e) None of the Above


Practice questions95

Practice Questions

  • Somatic neurons:

    a) Have a single neuron between the CNS and muscle fibre

    b) Each control a distinct motor unit

    c) Release ACh which binds adrenergic receptors

    d) Are afferent neurons

    e)A and B


Practice questions96

Practice Questions

  • Which is true of skeletal muscles?

    a) They can only contract

    b) They generate both motion and force

    c) They do not control the contractions of the heart

    d) They appear striated under a microscope

    e) All of the above


Practice questions97

Practice Questions

  • The role of Troponin

    a) Involves the binding of calcium ions

    b) Involves the interaction with nebulin

    c) Activates contraction in the absence of Ca+2

    d) Involves a direct interaction with ryanodine receptors

    e) None of the above


Practice questions98

Practice Questions

  • The Thin Filament is:

    a) Composed of G Actin

    b) Composed of F Actin

    c) Composed of Myosin

    d) Makes up the M Line

    e)Makes up the I Band

    f)B and E


Practice questions99

Practice Questions

  • The “Power Stroke” of a myosin molecule:

    a) Involves the release of ADP

    b) Requires Ca2+ to be bound to tropomyosin

    c) Moves consecutive Z discs further apart

    d) Requires the release of inorganic phosphate


Practice questions100

Practice Questions

  • At the motor end plate:

    a) ACh is bound nicotinic andrenergic receptors

    b) K+ efflux exceeds Na+ influx when Na+/K+ channels are open

    c) Curare can block receptors

    d) DHP receptors bind ACh


Practice questions101

Practice Questions

  • Muscles can use energy from:

    a) Oxidative phosphorylation

    b) ATP

    c) Glycolysis

    d) Creatine-Phosphate

    e) All of the above


Practice questions102

Practice Questions

  • Which is true of Slow-twitch oxidative muscle fibres?

    a) They have a lower threshold for recruitment then fast-twitch glycolytic

    b) They are easily fatigued

    c) They are Red in colour

    d) The have a fast myosin ATPase

    e) A and C

    f)B and D


Practice questions103

Practice Questions

  • Isometric muscle contraction:

    a) Moves the body

    b) Does not create force

    c) Has muscle length change

    d) Has sarcomeres shorten

    e) None of the above


Practice questions104

Practice Questions

  • β1 type receptors are:

    a) Cholinergic receptors

    b) Are responsive more to norepinephrine than epinephrine

    c) Increase cAMP production when active

    d) Increase cytosolic Ca+2 levels


Practice questions105

Practice Questions

  • The cheetah is the fastest land mammal on Earth. Its muscles are easily fatigued, produce high amounts of lactic acid and use glycogen as a primary source of energy. Cheetah muscles are likely made of what type of muscle fibres?

    a) Fast Oxidative

    b) Fast Glycolytic

    c) Slow Glycolytic

    d) Slow Oxidative


Practice questions106

Practice Questions

  • A 7 kg weight is held 24 cm from the elbow. The bicep is inserted 6 cm from elbow. How much force is required to keep the weight stationary?

    a) 28 kg

    b) 25 kg

    c) 42 kg

    d) 20 kg


Practice questions107

Practice Questions

  • Writer’s Cramp:

    a) Is a result of tetanus of the muscle

    b) Can be treated with botulinum toxin

    c) Can be treated by increasing ACh levels

  • A and B

  • All of the above


Practice questions108

Practice Questions

  • Multiunit smooth muscle cells are connected via gap junctions to conduct electric signals throughout the tissue:

    a) True

    b) False


Practice questions109

Practice Questions

  • Which of the following have equivalent functions in skeletal muscles and smooth muscles?

    a) Skeletal muscle troponin/Smooth Muscle troponin

    b) Dense Bodies/Z lines

    c) T Tubules/caveolae

    d) None of the above


Practice questions110

Practice Questions

  • Myosin Light Chain Kinase:

    a) Is activated by calmodulin when CaM is not bound to Ca2+

    b) Phosphorylates the heavy chain of myosin

    c) Derives energy from ATP

    d) Dephosphorylates Myosin in low Ca2+ conditions


Practice questions111

Practice Questions

  • Which is true with regard to cardiac muscle fibres

    a) They primarily undergo glycolysis for ATP production

    b) The are no t-tubules

    c) All cells are involved in contraction

    d) Undergo “all-or-none” style contraction

    e) None of the above


Practice questions112

Practice Questions

  • Phospholamban

    a) Regulates cardiac muscle contraction

    b) Increases SR Ca2+

    c) Decreases Ca2+ ATPase activity

    d) All of the above

    e) A and B


Practice questions113

Practice Questions

2

3

  • The Above Diagram represents:

    a) Smooth muscle action potential

    b) Cadiac pacemaker action potential

    c) Cardiac muscle action potential

    d) Neuron action potential

1

4


Practice questions114

Practice Questions

2

3

  • At the point marked “3”:

    a) Ca2+ channels are open

    b) Na+ channels are open

    c) Cardiac muscles are undergoing tetanus

    d) The cells are being rapidly hyperpolarized

1

4


Practice questions115

Practice Questions

  • The cardiovascular system is responsible for:

    a) Nutrient transport

    b) Hormone transport

    c) Transport of CO2+ from tissues to environment

    d) All of the Above


Practice questions116

Practice Questions

  • The right atrium pumps blood into ____ after receiving blood from ________

    a) Left Ventricle; the lungs

    b) The pulmonary artery; pulmonary vein

    c) Right Ventricle; Pulmonary vein

    d) Right Ventricle; venaecavae


Practice questions117

Practice Questions

  • The ______ Valve(s) help prevent backflow of blood into the atrium

    a) AV

    b) Tricuspid

    c) Bicuspid

    d) All of the above


Practice questions118

Practice Questions

  • Which of the following are true

    a) Chordaetendinae prevent the semilunar valves from being pushed back into atrium

    b) Semilunar valves prevent blood from flowing backwards into the aorta

    c) AV Valves close prior to atrial contraction

    d) The closing of the semilunar valves is the “dub” sound of the heart beat


Practice questions119

Practice Questions

  • The rate of packemaker potentials, and therefore the rate of heart contraction, can be increased by:

    a)Norepinephrine from parasympathetic neurons

    b)Acetylcholine from parasympathetic neurons

    c) Increasing K+ permeability

    d) Increased levels of cytosolcAMP


Practice questions120

Practice Questions

  • i. Purkinje Fibres

  • ii. AV Node

  • iii. Bundle of His

  • iv. SA Node

  • The correct pathway of conduction for cardiac cells to contract is:

    a) i, ii, iii, iv

    b) iv, ii, i, iii

    c) iv, ii, iii, i

    d) ii, iii, iv, i


Practice questions121

Practice Questions

  • Which of these is not a cause of arrhythmia

    a) SA node developing abnormal rate

    b) Cells in ventricle acting as pacemakers

    c) Blocking conduction through the AV node

    d) Closing of the AV valves


Practice questions122

Practice Questions

  • The region marked as T corresponds to:

    a) Atrial contraction

    b) Ventricular depolarization

    c) An irregular heart beat showing blocked AV conduction

    d) Ventricular repolarization


Practice questions123

Practice Questions

  • An incompletely closed heart valve can be diagnosed by what sound?

    a) lub

    b) dub

    c) clicking

    d) Whoosh

    e) All of the above are normal sounds


Practice questions124

Practice Questions

  • In the cardiac cycle which of the following means relaxation?

    a) Systole

    b) Stroke Volume

    c) Diastole

    d) All of the above


Practice questions125

Practice Questions

  • Which of the following is the thickest blood vessel?

    a) Capillary

    b) Arteriole

    c) Venule

    d)Artery


Practice questions126

Practice Questions

  • Blood Pressure:

    a) Is commonly measured in mm Hg

    b) Allows blood flow from high pressure to low pressure

    c) Has a kinetic and static component

    d) Is affected by friction and blood viscosity

    e) All of the above


Practice questions127

Practice Questions

  • If the diastolic pressure is 80 torr, and systolic pressure is 120 torr, what is the mean arterial pressure?

    a) 100 torr

    b) 93 torr

    c) 120 torr

    d) 90 torr


Practice questions128

Practice Questions

  • In conditions of high blood pressure, baroreceptors will fire

    a) More frequently

    b) Less frequently

    c) To send signals to the peripheral nervous system

    d) To send signals to increase vasoconstriction


Practice questions129

Practice Questions

  • Which of the following is not a granulocyte?

    a) Neutrophils

    b) Monocytes

    c) Mast Cells

    d)Eosinophils


Practice questions130

Practice Questions

  • Which of the following promotes O2 binding to haemoglobin?

    a) CO

    b) High temperature

    c) Replacing normal haemoglobin with fetalhaemoglobin

    d) Low pH


Practice questions131

Practice Questions

  • Which one of the cytokine:cell fate pairs is mismatched?

    a) EPO:RBC

    b) Thromopoietin:megakaryocytes

    c) Colony Stimulating Factor:Leukocytes

    d) All of the above are correctly matched


Practice questions132

Practice Questions

  • In the haemostatis pathway, what is the correct order of activation?

    a) Plasmin, Thrombin, Factor XII, Factor XIII

    b)Factor XII, Thrombin, Factor XIII, Plasmin

    c) Factor XII, Fibrin, Thrombin, Plasmin

    d) Factor XIII, Thrombin, Factor XII, Plasmin


Practice questions133

Practice Questions

  • Which of the following is not part of the upper respiratory system?

    a) Mouth

    b) Trachea

    c) Larynx

    d) Nasal Cavity


Practice questions134

Practice Questions

  • Disruption of Type II alveolar cell activity would result in:

    a) Decreased gas exchange with blood

    b) Lowered surfactant levels

    c) Emphysema

    d) Low lung compliance

    e) B and D

    f) C and D


Practice questions135

Practice Questions

  • Pneumothorax

    a) Is a collapsed lung

    b) Results from air being expelled from pleural cavity

    c) Can be treated by increased pleural fluid pressure

    d) Can be treated with the Heimlich manoeuvre


Practice questions136

Practice Questions

  • The volume of air that can be voluntarily moved via respiration:

    a) Is equivalent to the total lung capacity

    b) Is the total lung capacity minus the residual volume

    c) Is less than the inspiratory and expiratory reserve volumes

    d) Includes air left in lungs after maximum expiration


Practice questions137

Practice Questions

  • With respect to total pulmonary ventilation and alveolar ventilation:

    a) The two are always equal

    b) Total pulmonary ventilation reflects the amount of air that can exchange gas with blood

    c) Both depend on rate and depth of breathing

    d) None of the above


Practice questions138

Practice Questions

  • The _______ Respiratory Group controls ______ neurons and the external intercostal muscles. The Ventral Respiratory Group controls _______ and the internal intercostal muscles:

    a) Dorsal; inspiratory; expiration

    b) Ventral; expiratory; the diaphragm

    c) Dorsal; inspiratory; inspiration

    d) Central; inspiratory; expiration


Practice questions139

Practice Questions

  • Eosinophils:

    a) Have dark blue staining granulocytes

    b) Have a lifespan of several days

    c) Kill parasites through degranulation

    d) Are not found in the digestive tract


Practice questions140

Practice Questions

  • Monocytes:

    a) Will become macrophages in the tissue

    b) Will degrade dead cells

    c) Are APC’s

    d) Are not granulocytes

    e) All of the above


Practice questions141

Practice Questions

  • T cells develop in the_____

    a) GALT

    b)Tonsils

    c) Thymus (only mature here)

    d) Bone marrow


Practice questions142

Practice Questions

  • Thrombocytes

    a) Are not “true” cells

    b) Arise from megakaryocytes

    c) Are involved in blood clotting

    d) Are found in the blood where there is no damage

    e) All of the above


Practice questions143

Practice Questions

  • Cytotoxic T cells:

    a) Are part of the innate immune response

    b) Recognize antibodies on the MHC

    c) Are lymphocytes that produce granzymes

    d)Develop in the Bursa of Fabricius

    e) Bind to MHC found only on specialized immune cells


Practice questions144

Practice Questions

  • Which of the following are components of innate immunity?

    a) Skin

    b) B cells

    c) Natural Killer Cells

    d) Humoral immunity

    e) B and C

    f)A and C


Practice questions145

Practice Questions

  • The Membrane Attack Complex

    a) Is part of innate immunity

    b) Lyses cells through digestive enzymes

    c) Is formed by leukocytes

    d) Is constructed of blood proteins

    e) A and D


Practice questions146

Practice Questions

  • The Fab region of an antibody is responsible for __________, while the ____ region is determines the class of antibody

    a) Hinge Region, light chains

    b) Antigen Binding, IgA

    c) Antigen Binding, Fc

    d) Cytokine production, Arm

    e) Allergic responses, Y unit


Practice questions147

Practice Questions

  • The Fc region of an antibody is composed of:

    a) 1 heavy chain

    b) 2 heavy chains

    c) The arms of the antibody

    d) Two light chains

    e) Two light chains and two heavy chains


Practice questions148

Practice Questions

  • Interferon is synthesized:

    a) As part of the immune response to viruses

    b) As part of the immune response to bacteria

    c) By the infected cell/natural killer cells

    d) To opsonize pathogens for phagocytosis

    e) B and D

    f) A and C


Practice questions149

Practice Questions

  • IgE molecules

    a) Are antigens

    b) Are found in secretions

    c) Mediate allergic responses

    d) Are made by B cells

    e) A and D

    f) C and D


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