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Human Body: NERVOUS SYSTEM. Brain Diencephalon Spinal Cord Nerve. Nervous system = master control and communication. Three functions:. 1. Gathering Sensory input (information about stimuli). Integration (interpretation and decision-making about the stimuli). !.

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Human Body: NERVOUS SYSTEM

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Human Body: NERVOUS SYSTEM

BrainDiencephalonSpinal CordNerve


Nervous system = master control and communication

Three functions:

1. Gathering Sensory input (information about stimuli).

  • Integration (interpretation and decision-making about the stimuli).

!

3. Effects a response – motor output.

RUN AWAY!


Organization of the Nervous System

CNS:central nervous systemincludes brain and spinal cord

PNS:peripheral nervous systemincludes nerves


Organization of the Nervous System


Organization of the Nervous System

PNS:peripheral nervous systemincludes nerves


Afferent (Sensory) Division:conveys impulses to the CNS

Efferent (Motor) Division:conveys impulses from the CNS

Subdivisions:

Somatic/Voluntary NS Autonomic/Involuntary NS


Supporting Cells

Supporting the CNS:

Neuron = nerve cell

Nervous Tissue


Nervous Tissue

  • Supporting the CNS:

  • Neuroglia (Glia)

  • nerve glue cells

  • Astrocytes:

  • type of glial cell

  • 50% of nerve tissue

  • protect neurons from

  • harmful substances in blood


Nervous Tissue

Supporting the CNS:

Ependymal cells on the surface of the choroid plexus secrete cerebrospinal fluid.


Supporting the CNS:

Microglia found within the central nervous system are similar to macrophages.

Nervous Tissue


Supporting the CNS:

Extensions from the oligodendrocyte form the myelin sheaths of axons within the central nervous system.

Nervous Tissue


Nervous Tissue

Supporting the CNS:

Extension from the Schwann cell forms a myelin sheath called the neurilemma around each axon within the peripheral nervous system.


Nervous Tissue

Myelin sheath (blue)

No Myelin sheath


Anatomy of a Nerve Cell

Myelin Sheaths and Shingles

shingleshelpline.com

b4tea.com

healthinplainenglish.com

herpeszostervirus.com

emed.com.au

prlog.org


Nervous Tissue

Supporting the CNS:

Neuron cell bodies within ganglia are surrounded by satellite cells. Little is known of their function.


Anatomy of a Nerve Cell

Myelin Sheath

Node of Ranvier


Anatomy of a Nerve Cell

Dendrites conduct impulses toward the cell body.

Axons conduct impulses away from the cell body.


Anatomy of a Nerve Cell

CNS clusters of nerve cells = nuclei

PNS clusters of nerve cells = ganglia

ganglion

nuclei

neuromedia.neurobio.ucla.edu

eftlab.org


Anatomy of a Nerve Cell

Tracts = bundles of nerves in CNS

Nerves = bundles of nerves in the PNS

Tract

Nerves

spiltmartini.com


Anatomy of a Nerve Cell

Types of Sensory Receptors

1. Naked Nerve Endings = pain & temperature


Anatomy of a Nerve Cell

Types of Sensory Receptors

2. Meissner’s corpuscles = touch

kushtush.com

ttouchnorth.co.uk


Anatomy of a Nerve Cell

Types of Sensory Receptors

3. Pacinian corpuscle = deep pressure

russiablog.org

responsiblemarketing.com

impactlab.net


Anatomy of a Nerve Cell

  • Types of Sensory Receptors

  • Proprioceptors =

  • muscular stretching or tension

zimbio.com

webmd.com


Anatomy of a Nerve Cell

White matter = myelinated regions of the brain

Gray matter = unmyelinated regions of the brain

The Human Brain: How We Decide


Anatomy of a Nerve Cell

White matter and gray matter in MRI scans:

Comparing normal brain (left) with Huntington’s Diseased brain (right).

radlink.com.sg

wordadaywonder.com

http://player.discoveryeducation.com/index.cfm?guidAssetId=B1721030-D95E-45BF-B764-D4AC4026D0C0&blnFromSearch=1&productcode=US


The Nerve Impulse

  • Major functional properties:

  • Irritability

  • …ability to respond to stimuli

I am irritable! And…You are getting on my very last nerve!


The Nerve Impulse

Conductivity…ability to conduct electrical currents

  • Resting membrane –

    • Na+ and K+ levels are equal

Na+

Na+

Na+

Na+

Na+

Na+

K+

K+

K+

K+

K+

K+

Nerve impulses are “all-or-nothing” events.


Conductivity

The Nerve Impulse

  • B. Depolarization starts –

    • Na+ moves into nerve cell.

    • Cell depolarizes (becomes too + inside)Action Potential is generated.

Na+

Na+

Na+

Na+

Na+

Na+

Depolarization

K+

K+

K+

K+

K+

K+

K+

ACTION POTENTIAL

De = reversal


Conductivity

The Nerve Impulse

  • C. Action potential is propagated.

Na+

Na+

Na+

Na+

Na+

Na+

Depolarization

K+

K+

K+

K+

K+

K+

K+

K+

K+

K+

K+

K+

K+

ACTION POTENTIAL


Conductivity

The Nerve Impulse

Re = again

  • C. REpolarization.

REpolarization

K+

Na+

K+

Na+

K+

Na+

K+

Na+

K+

Na+

K+

Na+

Back to equal!

Too much + inside!

Nerve Impulse

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html


Nerve to Nerve

Neurotransmitter_Synapse_3D_Animation


  • Stimulation of Muscles:

  • An action potential arrives at a presynaptic terminal.

  • The Calcium ion channel opens releasing calcium ions into the presynaptic terminal.

  • Calcium ions cause the synaptic vesicle to move to the synaptic cleft.

  • The synaptic vesicle releases ACH neurotransmitter into the cleft.

  • ACH diffuses across the cleft and and binds to ACH receptors on the muscle fiber membrane.

  • Sodium channels open and release sodium into the muscle.

  • The muscle membrane depolarizes and a postsynaptic action potential results.

Ca+

Ca+

Ca+

Ca+

NA+

ACH

NA+

NA+


Reflexes

Auto = self

Reflex = rapid, predictable, involuntary response

ReflexArc = neural pathway of a reflex

(goes only one way)

Autonomic reflexes

regulate smooth muscles


Reflexes

Soma = body

http://www.sumanasinc.com/webcontent/animations/content/reflexarcs2.html

Somatic reflexes

stimulates skeletal muscles


Brain Stem

About the size of a thumb in diameter and about 3 inches long.

rainbowrehab.com


Brain Stem

Midbrain = small part that relays impulses and controls reflexes for vision and hearing.


Brain Stem

Pons = bridge

Pons = rounded structure of mostly fiber tracts involved in the control of breathing.


Brain Stem

Medula Oblongata = merges into spinal cord; regulates vital internal activities including heart rate, blood pressure, breathing, swallowing, vomiting, etc.


Brain Stem

Cerebellum = Outer gray matter; inner white matter. Provides timing for skeletal muscle activity, controls balance, and equilibrium. Compared to “autopilot” because it constantly checks and adjusts.

Ataxia = Clumsy and disorganized movements as a result of damage to the cerebellum.


Sheep Brain Dissection Lab

http://www.youtube.com/watch?v=08iZVEa5H9Y&feature=related


THE CNS

The BRAIN

http://www.youtube.com/watch?v=UFkSJemE4Pw

Brain Function and Anatomy

http://www.waiting.com/brainfunction.html


Brain Explorer

An interactive resource for knowledge about the human brain.

http://www.brainexplorer.org/brain_atlas/brainatlas_index.shtml

Bon Voyage! Go Explore the Brain.


BRAIN FUN!

RIGHT BRAIN VS LEFT BRAIN

http://www.wherecreativitygoestoschool.com/vancouver/left_right/rb_test.htm

http://homeworktips.about.com/library/brainquiz/bl_leftrightbrain_quiz.htm

http://similarminds.com/brain.html

http://frank.mtsu.edu/~studskl/hd/learn.html

What are your results? Are you right or left brained?

What does it mean?


Nervous System

Protection of CNS

Meninges = three membranes covering the CNS structures (p 211)

Duramater = outermost layer

Dura = hard

Mater = mother

netterimages.com

schools-wikipedia.org


Arachnoid Mater = web-like middle layer

commons.wikimedia.org

Arachno = spider


Pia Mater = innermost layer following folds

commons.wikimedia.org

Sheep Brain Dissection http://www.youtube.com/watch?v=vE3Yf_xy_mE

pia = gentle


Meningitis = inflammation of meninges

http://video.about.com/infectiousdiseases/Meningitis.htm

http://www.nmaus.org/programs/getting-it/

http://www.healthline.com/hgy-transcripts/meningitis-overview

http://healthline.healthology.com/hybrid/hybrid-autodetect.aspx?content_id=2582&focus_handle=childrens-diseases&brand_name=healthline


Cerebrospinal Fluid (CSF) = fluid surrounding the brain and spinal cord

Continually made from blood plasma in choroid plexuses which hang from the “roof” of the brains ventricles.

Circulates continuously by being produced and then drained back into blood plasma to keep a constant volume of about 150 ml.

Function: protection

Spinal Tap = sampling technique to test CSF.

Hydrocephalus = “water on the brain”


Keeps neurons separated from blood-borne substances.

BLOOD-BRAIN BARRIER

Made of LEAST PERMEABLE capillaries in the body.

Can’t keep out fats, respiratory gases, alcohol, nicotine, or anesthetics.

vandenberg.af.mil


Brain Injuries

Traumatic Brain Injuries and Brain Dysfunctions

Head injuries are the leading cause of accidental death in the USA.

Concussion = slight injury, dizziness, brief loss of consciousness.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000034&ptid=17

Contusion = marked tissue destruction, coma

Cerebral Edema = swelling of the brain, death


Stroke = cerebrovascular accident (CVA) occurs when circulation is cut off to the brain.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000123&ptid=17

Aphasia = result of damage to left cerebral hemisphere, affects speech.

motor aphasia = affects Broca’s area and loss of speechsensory aphasia = loss of understanding of language

TIA = transient ischemic attack (mini-stroke)

BrainMatters 54:00 http://video.pbs.org/video/1390247671/


  • Alzheimer’s Disease

  • mental deterioration

  • progressive degenerative disease

  • originally called “senile dementia”

  • memory loss, irritability, moodiness, confusion, possibly violent

  • later stages include hallucinations

articles.mercola.com

topnews.net.nz

Dementia 1:01 http://www.healthscout.com/animation/1/7/main.html

Alzheimer’s Disease 19:10 http://www.alzheimer.ca/english/disease/whatisit-video.htm


Alzheimer’s Disease


Parkinson’s Disease

Interactive tutorial http://www.nlm.nih.gov/medlineplus/tutorials/parkinsonsdisease/htm/index.htm

Parkinson’s Disease Treatment http://www.edheads.org/activities/brain_stimulation/


Spinal Cord

About 17 inches (42 cm) long.

31 pairs of nerves arise from it.


Association neurons

Sensory neurons

Motor neurons


White matter of the spinal cord


Quadriplegic = damage high in cord

Paraplegic = damage low in cord


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