Transcript Slide 1

Human Body: NERVOUS SYSTEM
Brain
Diencephalon
Spinal Cord
Nerve
Nervous system = master control and communication
Three functions:
1. Gathering Sensory input (information about stimuli).
2. Integration (interpretation
and decision-making about
the stimuli).
3. Effects a response – motor
output.
Organization of the Nervous System
CNS:
central nervous system
includes brain and spinal cord
PNS:
peripheral nervous system
includes nerves
Organization of the Nervous System
Organization of the Nervous System
PNS:
peripheral nervous system
includes nerves
Afferent (Sensory) Division:
Efferent (Motor) Division:
conveys impulses to the CNS
conveys impulses from the CNS
Subdivisions:
Somatic/Voluntary NS
Autonomic/Involuntary NS
Nervous Tissue
Supporting the CNS:
Neuron = nerve cell
Supporting Cells
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:
Nervous Tissue
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
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
b4tea.com
shingleshelpline.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
Axons conduct
impulses away
from the cell body.
Dendrites conduct
impulses toward 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
4. 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).
wordadaywonder.com
radlink.com.sg
http://player.discoveryeducation.com/index.cfm?guidAssetId=B1721030-D95E-45BFB764-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 currents
A. 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.
Depolarization
Na+
Na+
Na+ Na+ Na+ Na+
K+
K+
K+
ACTION
POTENTIAL
K+
K+
K+
De = reversal
Conductivity
The Nerve Impulse
C. Action potential is propagated.
Depolarization
Na+
Na+
Na+ Na+ Na+
Na+
K+
K+
K+
K+
ACTION
POTENTIAL
K+
K+
The Nerve Impulse
Re = again
REpolarization
Conductivity
C. REpolarization.
K+Na+K+Na+K+Na+K+ Na+
K+
Na+K+Na+
Back
Too much
to+equal!
inside!
Nerve Impulse
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html
Nerve to Nerve
Neurotransmitter_Synap
se_3D_Animation
Stimulation of Muscles:
Ca+
Ca+
Ca+
Ca+
NA+
NA+
ACH
NA+
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.
Reflexes
Auto = self
Reflex = rapid, predictable, involuntary response
Reflex Arc = neural pathway of a reflex
(goes only one way)
Autonomic reflexes
regulate smooth muscles
Reflexes
Soma = body
http://www.sumanasinc.com/webcontent/an
imations/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
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/braina
tlas_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
pia = gentle
Sheep Brain Dissection
http://www.youtube.com/watch?v=vE3Yf_xy_mE
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/hybridautodetect.aspx?content_id=2582&focus_handle=childrensdiseases&brand_name=healthline
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”
Cerebrospinal Fluid
(CSF) = fluid surrounding
the brain and spinal cord
Keeps neurons separated from
blood-borne substances.
BLOOD-BRAIN BARRIER
Made of LEAST PERMEABLE
capillaries in the body.
vandenberg.af.mil
Can’t keep out
fats, respiratory
gases, alcohol,
nicotine, or
anesthetics.
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_DisplayAnimatio
n.aspx?gcid=000123&ptid=17
Aphasia = result of damage to left cerebral hemisphere, affects
speech.
motor aphasia = affects Broca’s area and loss of speech
sensory 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
topnews.net.nz
articles.mercola.com
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/tutorial
s/parkinsonsdisease/htm/index.htm
Parkinson’s Disease Treatment
http://www.edheads.org/activities/brain_sti
mulation/
Spinal Cord
About 17 inches (42 cm) long.
31 pairs of nerves arise from it.
Motor neurons
Sensory neurons
Association neurons
White matter of the spinal cord
Quadriplegic = damage high in cord
Paraplegic = damage low in cord