Gastrovascular cavities
This presentation is the property of its rightful owner.
Sponsored Links
1 / 69

Gastrovascular Cavities PowerPoint PPT Presentation


  • 33 Views
  • Uploaded on
  • Presentation posted in: General

Gastrovascular Cavities. Simple animals, such as cnidarians , have a body wall only two cells thick that encloses a gastrovascular cavity This cavity functions in both digestion and distribution of substances throughout the body

Download Presentation

Gastrovascular Cavities

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Gastrovascular cavities

Gastrovascular Cavities

  • Simple animals, such as cnidarians, have a body wall only two cells thick that encloses a gastrovascular cavity

  • This cavity functions in both digestion and distribution of substances throughout the body

  • Some cnidarians, such as jellies, have elaborate gastrovascular cavities


Gastrovascular cavities

Circular

canal

Radial canal

Mouth

5 cm


Open and closed circulatory systems

Open and Closed Circulatory Systems

  • More complex animals have either open or closed circulatory systems

  • Both systems have three basic components:

    • A circulatory fluid (blood or hemolymph)

    • A set of tubes (blood vessels)

    • A muscular pump (the heart)


Gastrovascular cavities

  • In insects, other arthropods, and most molluscs blood bathes the organs directly in an open circulatory system

  • There is no distinction between blood and interstitial fluid, and this general body fluid is more correctly called hemolymph

  • In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluid

  • Closed systems are more efficient at transporting circulatory fluids to tissues and cells


Gastrovascular cavities

Heart

Heart

Hemolymph in sinuses

surrounding organs

Interstitial

fluid

Small branch vessels

in each organ

Lateral

vessel

Anterior

vessel

Ostia

Dorsal vessel

(main heart)

Tubular heart

Auxiliary hearts

Ventral vessels

An open circulatory system.

A closed circulatory system.


Survey of vertebrate circulation

Survey of Vertebrate Circulation

  • Humans and other vertebrates have a closed circulatory system, often called the cardiovascular system

  • Blood flows in a closed cardiovascular system, consisting of blood vessels and a two- to four-chambered heart

  • Arteries carry blood to capillaries, the sites of chemical exchange between the blood and interstitial fluid

  • Veins return blood from capillaries to the heart


Le 42 4

LE 42-4

FISHES

AMPHIBIANS

REPTILES (EXCEPT BIRDS)

MAMMALS AND BIRDS

Gill capillaries

Lung and skin capillaries

Lung capillaries

Lung capillaries

Pulmocutaneous

circuit

Pulmonary

circuit

Gill

circulation

Pulmonary

circuit

Right

systemic

aorta

Artery

Heart:

Ventricle (V)

Left

systemic

aorta

A

A

A

A

A

A

Atrium (A)

V

V

V

V

V

Right

Left

Left

Right

Right

Left

Systemic

circulation

Systemic

circuit

Systemic

circuit

Vein

Systemic capillaries

Systemic capillaries

Systemic capillaries

Systemic capillaries

Systemic circuits include all body tissues except lungs. Note that circulatory systems are depicted as if the animal is facing you: with the right side of the heart shown at the left and vice-versa.


Mammalian circulation the pathway

Mammalian Circulation: The Pathway

  • Heart valves dictate a one-way flow of blood through the heart

  • Blood begins its flow with the right ventricle pumping blood to the lungs

  • In the lungs, the blood loads O2 and unloads CO2

  • Oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped to the body tissues by the left ventricle

  • Blood returns to the heart through the right atrium


Gastrovascular cavities

Capillaries of

head and

forelimbs

Anterior

vena cava

Pulmonary

artery

Pulmonary

artery

Aorta

Capillaries

of right lung

Capillaries

of left lung

Pulmonary

vein

Pulmonary

vein

Right atrium

Left atrium

Left ventricle

Right ventricle

Posterior

vena cava

Aorta

Capillaries of

abdominal organs

and hind limbs


Gastrovascular cavities

Pulmonary artery

Aorta

Anterior

vena cava

Pulmonary

artery

Right

atrium

Left

atrium

Pulmonary

veins

Pulmonary

veins

Semilunar

valve

Semilunar

valve

Atrioventricular

valve

Atrioventricular

valve

Posterior

vena cava

Left

ventricle

Right

ventricle


Gastrovascular cavities

  • The heart contracts and relaxes in a rhythmic cycle called the cardiac cycle

  • The contraction, or pumping, phase is called systole

  • The relaxation, or filling, phase is called diastole

  • The heart rate, also called the pulse, is the number of beats per minute

  • The cardiac output is the volume of blood pumped into the systemic circulation per minute


Gastrovascular cavities

  • The sinoatrial (SA) node, or pacemaker, sets the rate and timing at which cardiac muscle cells contract

  • Impulses from the SA node travel to the atrioventricular (AV) node

  • At the AV node, the impulses are delayed and then travel to the Purkinje fibers that make the ventricles contract

  • Impulses that travel during the cardiac cycle can be recorded as an electrocardiogram (ECG or EKG)


Gastrovascular cavities

The pacemaker is influenced by nerves, hormones, body temperature, and exercise

Signals pass

to heart apex.

Signals are delayed

at AV node.

Pacemaker

generates wave of

signals to contract.

Signals spread

throughout

ventricles.

SA node

(pacemaker)

AV

node

Bundle

branches

Purkinje

fibers

Heart

apex

ECG


Gastrovascular cavities

Vein

Artery

100 µm

Endothelium

Valve

Basement

membrane

Endothelium

Endothelium

Smooth

muscle

Smooth

muscle

Capillary

Connective

tissue

Connective

tissue

Vein

Artery

Venule

Arteriole


Blood vessel structure and function

Blood Vessel Structure and Function

  • Structural differences in arteries, veins, and capillaries correlate with functions

  • Arteries have thicker walls that accommodate the high pressure of blood pumped from the heart

  • In the thinner-walled veins, blood flows back to the heart mainly as a result of muscle action


Gastrovascular cavities

Direction of blood flow

in vein (toward heart)

Valve (open)

Skeletal muscle

Valve (closed)


Blood flow velocity

Blood Flow Velocity

  • Physical laws governing movement of fluids through pipes affect blood flow and blood pressure

  • Velocity of blood flow is slowest in the capillary beds, as a result of the high resistance and large total cross-sectional area


Gastrovascular cavities

5,000

4,000

3,000

Area (cm2)

2,000

1,000

0

50

40

Velocity (cm/sec)

30

20

10

0

120

Systolic

pressure

100

80

Pressure (mm Hg)

60

Diastolic

pressure

40

20

0

Venae cavae

Aorta

Capillaries

Venules

Veins

Arterioles

Arteries


Blood pressure

Blood Pressure

  • Blood pressure is the hydrostatic pressure that blood exerts against the wall of a vessel

  • Systolic pressure is the pressure in the arteries during ventricular systole; it is the highest pressure in the arteries

  • Diastolic pressure is the pressure in the arteries during diastole; it is lower than systolic pressure

  • Blood pressure is determined by cardiac output and peripheral resistance due to constriction of arterioles


Gastrovascular cavities

Blood pressure

reading: 120/70

Pressure

in cuff

below 120

Pressure

in cuff

below 70

Pressure

in cuff

above 120

Rubber cuff

inflated

with air

120

120

70

Sounds

audible in

stethoscope

Sounds

stop

Artery

closed

Artery


Capillary function

Capillary Function

  • Capillaries in major organs are usually filled to capacity

  • Two mechanisms regulate distribution of blood in capillary beds:

    • Contraction of the smooth muscle layer in the wall of an arteriole constricts the vessel

    • Precapillary sphincters control flow of blood between arterioles and venules


Gastrovascular cavities

Thoroughfare

channel

Precapillary sphincters

Venule

Arteriole

Capillaries

Sphincters relaxed

Venule

Arteriole

Sphincters contracted


Gastrovascular cavities

  • The critical exchange of substances between the blood and interstitial fluid takes place across the thin endothelial walls of the capillaries

  • The difference between blood pressure and osmotic pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end


Gastrovascular cavities

Tissue cell

INTERSTITIAL FLUID

Net fluid

movement out

Net fluid

movement in

Capillary

Capillary

Red

blood

cell

15 µm

Direction of

blood flow

Blood pressure

Osmotic pressure

Inward flow

Pressure

Outward flow

Arterial end of capillary

Venous end


Fluid return by the lymphatic system

Fluid Return by the Lymphatic System

  • The lymphatic system returns fluid to the body from the capillary beds

  • This system aids in body defense

  • Fluid reenters the circulation directly at the venous end of the capillary bed and indirectly through the lymphatic system


Blood composition and function

Blood Composition and Function

  • Blood consists of several kinds of cells suspended in a liquid matrix called plasma

  • The cellular elements occupy about 45% of the volume of blood


Plasma

Plasma

  • Blood plasma is about 90% water

  • Among its solutes are inorganic salts in the form of dissolved ions, sometimes called electrolytes

  • Another important class of solutes is the plasma proteins, which influence blood pH, osmotic pressure, and viscosity

  • Various plasma proteins function in lipid transport, immunity, and blood clotting


Gastrovascular cavities

Plasma 55%

Cellular elements 45%

Constituent

Major functions

Cell type

Number

Functions

Water

Solvent for

carrying other

substances

per µL (mm3) of blood

Erythrocytes

(red blood cells)

Ions (blood electrolytes)

5–6 million

Transport oxygen

and help transport

carbon dioxide

Sodium

Potassium

Calcium

Magnesium

Chloride

Bicarbonate

Osmotic balance,

pH buffering, and

regulation of

membrane

permeability

Separated

blood

elements

Leukocytes

(white blood cells)

Defense and

immunity

5,000–10,000

Plasma proteins

Osmotic balance,

pH buffering

Albumin

Lymphocyte

Basophil

Fibrinogen

Clotting

Defense

Immunoglobulins

(antibodies)

Eosinophil

Substances transported by blood

Monocyte

Neutrophil

Nutrients (such as glucose, fatty acids,

vitamins)

Waste products of metabolism

Respiratory gases (O2 and CO2)

Hormones

Platelets

250,000–

400,000

Blood clotting


Cellular elements

Cellular Elements

  • Suspended in blood plasma are two types of cells:

    • Red blood cells (erythrocytes) transport oxygen

    • White blood cells (leukocytes) function in defense

  • Platelets, a third cellular element, are fragments of cells that are involved in clotting


Gastrovascular cavities

  • Red blood cells, or erythrocytes, are by far the most numerous blood cells

  • There are five major types of white blood cells, or leukocytes: monocytes, neutrophils, basophils, eosinophils, and lymphocytes

  • They function in defense by phagocytizing bacteria and debris or by producing antibodies

  • Erythrocytes, leukocytes, and platelets all develop from a common source, pluripotent stem cells in the red marrow of bones


Gastrovascular cavities

Pluripotent stem cells

(in bone marrow)

Myeloid

stem cells

Lymphoid

stem cells

Basophils

B cells

T cells

Lymphocytes

Eosinophils

Neutrophils

Erythrocytes

Platelets

Monocytes


Blood clotting

Blood Clotting

  • When the endothelium of a blood vessel is damaged, the clotting mechanism begins

  • A cascade of complex reactions converts fibrinogen to fibrin, forming a clot


Gastrovascular cavities

Endothelium of

vessel is damaged,

exposing connective

tissue; platelets adhere

Platelets form a plug

Seal is reinforced by a clot of fibrin

Collagen fibers

Fibrin clot

Red blood cell

Platelet plug

Platelet releases chemicals

that make nearby platelets sticky

Clotting factors from:

Platelets

Damaged cells

Plasma (factors include calcium, vitamin K)

Prothrombin

Thrombin

Fibrinogen

Fibrin

5 µm


Gastrovascular cavities

Connective

tissue

Smooth

muscle

Endothelium

Plaque

50 µm

Normal artery

Partly clogged artery

250 µm


Cardiovascular disease

Cardiovascular Disease

  • Hypertension, or high blood pressure, promotes atherosclerosis and increases the risk of heart attack and stroke

  • A heart attack is the death of cardiac muscle tissue resulting from blockage of one or more coronary arteries

  • A stroke is the death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head


Gas exchange occurs across specialized respiratory surfaces

Gas exchange occurs across specialized respiratory surfaces

  • Gas exchange supplies oxygen for cellular respiration and disposes of carbon dioxide

  • Animals require large, moist respiratory surfaces for adequate diffusion of gases between their cells and the respiratory medium, either air or water


Gastrovascular cavities

Respiratory

medium

(air or water)

Respiratory

surface

O2

CO2

Organismal

level

Circulatory system

Cellular level

Energy-rich

fuel molecules

from food

ATP

Cellular respiration


Gills in aquatic animals

Gills in Aquatic Animals

  • Gills are outfoldings of the body surface specialized for gas exchange

  • In some invertebrates, gills have a simple shape and are distributed over much of the body

  • Many segmented worms have flaplike gills that extend from each segment of their body

  • The gills of clams, crayfish, and many other animals are restricted to a local body region


Gastrovascular cavities

Gills

Coelom

Tube foot

Sea star


Gastrovascular cavities

Parapodia

Gill

Marine worm


Gastrovascular cavities

Gills

Scallop


Gastrovascular cavities

Gills

Crayfish


Gastrovascular cavities

  • Effectiveness of gas exchange in some gills, including those of fishes, is increased by ventilation and the countercurrent flow of blood and water


Gastrovascular cavities

Oxygen-poor

blood

Lamella

Oxygen-rich

blood

Gill

arch

Blood

vessel

Gill

arch

15%

40%

70%

Water

flow

5%

30%

Operculum

60%

100%

90%

Water flow

over lamellae

showing % O2

O2

Blood flow

through capillaries

in lamellae

showing % O2

Gill

filaments

Countercurrent exchange


Tracheal systems in insects

Tracheal Systems in Insects

  • The tracheal system of insects consists of tiny branching tubes that penetrate the body

  • The tracheal tubes supply O2 directly to body cells


Gastrovascular cavities

Tracheae

Air sacs

Spiracle


Gastrovascular cavities

Body

cell

Air

sac

Tracheole

Trachea

Air

Body wall

Mitochondria

Tracheoles

Myofibrils

2.5 µm


Lungs

Lungs

  • Spiders, land snails, and most terrestrial vertebrates have internal lungs

  • An amphibian such as a frog ventilates its lungs by positive pressure breathing, which forces air down the trachea


Mammalian respiratory systems a closer look

Mammalian Respiratory Systems: A Closer Look

  • A system of branching ducts conveys air to the lungs

  • Air inhaled through the nostrils passes through the pharynx into the trachea, bronchi, bronchioles, and dead-end alveoli, where gas exchange occurs


Gastrovascular cavities

Branch

from

pulmonary

artery

(oxygen-poor

blood)

Branch

from

pulmonary

vein

(oxygen-rich

blood)

Terminal

bronchiole

Nasal

cavity

Pharynx

Alveoli

Larynx

Left

lung

Esophagus

50 µm

Trachea

Right

lung

50 µm

Bronchus

Bronchiole

Diaphragm

Heart

Colorized SEM

SEM


How a bird breathes

How a Bird Breathes

  • Birds have eight or nine air sacs that function as bellows that keep air flowing through the lungs

  • Air passes through the lungs in one direction only

  • Every exhalation completely renews the air in the lungs


Gastrovascular cavities

Air

Air

Anterior

air sacs

Trachea

Posterior

air sacs

Lungs

Lungs

Air tubes

(parabronchi)

in lung

1 mm

INHALATION

Air sacs fill

EXHALATION

Air sacs empty; lungs fill


How a mammal breathes

How a Mammal Breathes

  • Mammals ventilate their lungs by negative pressure breathing, which pulls air into the lungs

  • Lung volume increases as the rib muscles and diaphragm contract


Gastrovascular cavities

Rib cage gets

smaller as

rib muscles

relax

Rib cage

expands as

rib muscles

contract

Air

inhaled

Air

exhaled

Lung

Diaphragm

EXHALATION

Diaphragm relaxes

(moves up)

INHALATION

Diaphragm contracts

(moves down)


Control of breathing in humans

Control of Breathing in Humans

  • In humans, the main breathing control centers are in two regions of the brain, the medulla oblongata and the pons

  • The medulla regulates the rate and depth of breathing in response to pH changes in the cerebrospinal fluid

  • The medulla adjusts breathing rate and depth to match metabolic demands


Gastrovascular cavities

Cerebrospinal

fluid

Pons

Breathing

control

centers

Medulla

oblongata

Carotid

arteries

Aorta

Diaphragm

Rib muscles


The role of partial pressure gradients

The Role of Partial Pressure Gradients

  • Gases diffuse down pressure gradients in the lungs and other organs

  • Diffusion of a gas depends on differences in a quantity called partial pressure

  • A gas diffuses from a region of higher partial pressure to a region of lower partial pressure

  • In the lungs and tissues, O2 and CO2 diffuse from where their partial pressures are higher to where they are lower


Gastrovascular cavities

Exhaled air

Inhaled air

120

27

160

0.2

Alveolar spaces

O2

CO2

CO2

O2

104

40

Alveolar

epithelial

cells

O2

CO2

CO2

O2

Blood

leaving

alveolar

capillaries

Blood

entering

alveolar

capillaries

CO2

O2

Alveolar

capillaries

of lung

40

45

104

40

O2

CO2

CO2

O2

Pulmonary

arteries

Pulmonary

veins

Systemic

veins

Systemic

arteries

Heart

Tissue

capillaries

O2

CO2

Blood

entering

tissue

capillaries

Blood

leaving

tissue

capillaries

O2

CO2

40

45

100

40

O2

CO2

CO2

O2

Tissue

cells

< 40

> 45

O2

CO2


Respiratory pigments

Respiratory Pigments

  • Respiratory pigments, proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry

  • The respiratory pigment of almost all vertebrates is the protein hemoglobin, contained in erythrocytes

  • Like all respiratory pigments, hemoglobin must reversibly bind O2, loading O2 in the lungs and unloading it in other parts of the body


Gastrovascular cavities

Heme group

Iron atom

O2 loaded

in lungs

O2 unloaded

in tissues

Polypeptide chain


Gastrovascular cavities

  • Loading and unloading of O2 depend on cooperation between the subunits of the hemoglobin molecule

  • The binding of O2 to one subunit induces the other subunits to bind O2 with more affinity

  • Cooperative O2 binding and release is evident in the dissociation curve for hemoglobin

  • A drop in pH lowers affinity of hemoglobin for O2


Gastrovascular cavities

100

O2 unloaded from

hemoglobin

during normal

metabolism

80

60

O2 saturation of hemoglobin (%)

O2 reserve that can

be unloaded from

hemoglobin to

tissues with high

metabolism

40

20

0

0

20

40

60

80

100

Lungs

Tissues during

exercise

Tissues

at rest

P(mm Hg)

O2

Pand hemoglobin dissociation at 37°C and pH 7.4

O2


Gastrovascular cavities

100

pH 7.4

80

Bohr shift:

additional O2

released from

hemoglobin at

lower pH

(higher CO2

concentration)

O2 saturation of hemoglobin (%)

60

pH 7.2

40

20

0

0

20

40

60

80

100

P(mm Hg)

O2

pH and hemoglobin dissociation


Carbon dioxide transport

Carbon Dioxide Transport

  • Hemoglobin also helps transport CO2 and assists in buffering

  • Carbon from respiring cells diffuses into the blood plasma and then into erythrocytes and is ultimately released in the lungs


Gastrovascular cavities

Tissue cell

CO2 transport

from tissues

CO2 produced

Interstitial

fluid

CO2

CO2

Capillary

wall

Blood plasma

within capillary

CO2

H2O

Hemoglobin

picks up

CO2 and H+

Red

blood

cell

H2CO3

Carbonic acid

Hb

HCO3–

Bicarbonate

H+

+

HCO3–

To lungs

CO2 transport

to lungs

HCO3–

HCO3–

H+

+

Hemoglobin

releases

CO2 and H+

Hb

H2CO3

H2O

CO2

CO2

CO2

CO2

Alveolar space in lung


Animations and videos

Animations and Videos

  • Human Circulatory System

  • Bozeman - The Circulatory System

  • Cardiovascular System I: The Beating Heart

  • Cardiovascular System II: The Vascular Highway

  • Conducting System of the Heart

  • Cardiac Cycle – 1

  • Cardiac Cycle – 2

  • Cardiac Cycle - 3


Animations and videos1

Animations and Videos

  • Blood Flow Through The Human Heart

  • A Beating Heart Cell

  • Measuring Blood Pressure

  • Baroreceptor Reflex Control of Blood Pressure

  • Chemoreceptor Reflex Control of Blood Pressure

  • Hemoglobin Breakdown

  • Path of Blood

  • Blood to Tissue


Animations and videos2

Animations and Videos

  • Tissues to Blood

  • Blood to Lungs

  • Lungs to Blood

  • Bozeman - Interstitial Fluid

  • Hearts and other Pumps in Animals

  • The Pleural Membranes

  • Bozeman - The Respiratory System

  • Gas Exchange During Respiration


Animations and videos3

Animations and Videos

  • Changes in the Partial Pressures of Oxygen and Carbon Dioxide

  • Alveolar Pressure Changes During Inspiration and Expiration

  • Changes in the Partial Pressure of CO2 and O2

  • Airflow in Mammals

  • Airflow in Birds

  • Chapter Quiz Questions – 1

  • Chapter Quiz Questions - 2


  • Login