Human Body: NERVOUS SYSTEM Brain Diencephalon Spinal Cord Nerve

Human Body: NERVOUS SYSTEM

BrainDiencephalonSpinal CordNerve

BrainDiencephalonSpinal CordNerve

Nervous system = master control and communication

Three functions:

!2. Integration (interpretation

and decision-making about the stimuli).

3. Effects a response – motor output.

RUN AWAY!

1. Gathering Sensory input (information about stimuli).

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 CNSAfferent (Sensory) Division:conveys impulses to the CNS

Efferent (Motor) Division:conveys impulses from the CNSSubdivisions: Somatic/Voluntary NS Autonomic/Involuntary NS

Efferent (Motor) Division:conveys impulses from the CNSSubdivisions: Somatic/Voluntary NS Autonomic/Involuntary NS

Nervous TissueSupporting Cells

Supporting the CNS:

Neuron = nerve cell

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 TissueSupporting the CNS:

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

Nervous TissueSupporting the CNS:

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

Nervous TissueSupporting the CNS:

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

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

Myelin Sheaths and Shingles

Anatomy of a Nerve Cell

prlog.orgemed.com.auherpeszostervirus.comshingleshelpline.com

healthinplainenglish.comb4tea.com

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

Axons conduct impulses away from the cell body.

Anatomy of a Nerve CellDendrites conduct impulses toward the cell body.

Anatomy of a Nerve Cell

CNS clusters of nerve cells = nucleiPNS clusters of nerve cells = ganglia

nuclei

eftlab.org

ganglion

neuromedia.neurobio.ucla.edu

Anatomy of a Nerve Cell

spiltmartini.com

Tracts = bundles of nerves in CNSNerves = bundles of nerves in the PNSTracts = bundles of nerves in CNSNerves = bundles of nerves in the PNS

Tract

Nerves

Anatomy of a Nerve Cell

Types of Sensory Receptors

1. Naked Nerve Endings = pain & temperature

Types of Sensory Receptors

1. Naked Nerve Endings = pain & temperature

Anatomy of a Nerve Cell

Types of Sensory Receptors

2. Meissner’s corpuscles = touch

Types of Sensory Receptors

2. Meissner’s corpuscles = touch

ttouchnorth.co.uk

kushtush.com

Anatomy of a Nerve Cell

Types of Sensory Receptors

3. Pacinian corpuscle = deep pressure

Types of Sensory Receptors

3. Pacinian corpuscle = deep pressure

responsiblemarketing.com

impactlab.net

russiablog.org

Anatomy of a Nerve Cell

Types of Sensory Receptors

4.Proprioceptors = muscular

stretching or tension

Types of Sensory Receptors

4.Proprioceptors = muscular

stretching or tension

zimbio.comwebmd.com

Anatomy of a Nerve Cell

White matter = myelinated regions of the brainGray 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:

wordadaywonder.comradlink.com.sgComparing normal brain (left) with Huntington’s Diseased brain (right).

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

The Nerve Impulse

Major functional properties:

1.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 currentsA. Resting membrane –

Na+ and K+ levels are equal

Na+

K+

Na+Na+Na+Na+Na+

K+K+K+K+K+

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

The Nerve Impulse Conductivity B. Depolarization starts –

Na+ moves into nerve cell.Cell depolarizes (becomes too + inside) Action Potential is generated.

K+

Na+

K+K+K+K+K+

Na+ Na+

K+

ACTION POTENTIAL

Depolarization

Na+ Na+ Na+

De = reversal

The Nerve Impulse Conductivity C. Action potential is propagated.

K+ K+K+K+K+K+ K+

ACTION POTENTIAL

Depolarization K+K+ K+K+ K+K+

Na+ Na+ Na+ Na+ Na+ Na+

The Nerve Impulse Conductivity

C. REpolarization.

K+ K+ K+REpolarization K+ K+ K+Na+ Na+ Na+ Na+ Na+ Na+

Too much + inside!Back to equal!

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

Re = again

Nerve to Nerve

Neurotransmitter_Synapse_3D_Animation

Stimulation of Muscles:1. An action potential arrives at

a presynaptic terminal.2. The Calcium ion channel

opens releasing calcium ions into the presynaptic terminal.

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

4. The synaptic vesicle releases ACH neurotransmitter into the cleft.

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

6. Sodium channels open and release sodium into the muscle.

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

NA+ACH

Ca+

Ca+

Ca+

Ca+

NA+

NA+

Reflexes

Reflex = rapid, predictable, involuntary responseReflex Arc = neural pathway of a reflex (goes only one way)

Autonomic reflexesregulate smooth muscles

Auto = self

Reflexes

Somatic reflexes stimulates skeletal muscles

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

Soma = body

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

Pons = bridge

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.

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

Sheep Brain Dissection Lab

THE CNS

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

Brain Function and Anatomyhttp://www.waiting.com/brainfunction.html

The BRAIN

Brain Explorer

An interactive resource for knowledge about the human brain.

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

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.

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

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

BRAIN FUN!RIGHT BRAIN VS LEFT BRAIN

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

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

Duramater = outermost layer

Dura = hardMater = motherDura = hardMater = mother

netterimages.com

schools-wikipedia.org

Protection of CNSProtection of CNS

Arachnoid Mater = web-like middle layer

Arachno = spiderArachno = spider

commons.wikimedia.org

Pia Mater = innermost layer following folds

pia = gentlepia = gentle

commons.wikimedia.org

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

Meningitis = inflammation of meninges

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

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

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

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

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”

BLOOD-BRAIN BARRIER Keeps neurons separated from blood-borne substances.

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 DysfunctionsTraumatic 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

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

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)

Alzheimer’s Disease

• mental deterioration• progressive degenerative disease• originally called “senile dementia”• memory loss, irritability, moodiness, confusion, possibly violent• later stages include hallucinations

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

articles.mercola.com

topnews.net.nz

Alzheimer’s Disease

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

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

Parkinson’s Disease

Spinal Cord

About 17 inches (42 cm) long.31 pairs of nerves arise from it.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