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The Central Nervous System
Meninges
1. Definition: Protective membranes between
bone and nervous system soft tissues
2. Made of 3 layers
a. Dura mater (tough mother)
-outermost layer
b. Arachnoid mater (spider mother)
-middle layer
c. Pia mater (delicate mother)
-inner layer
Cerebrospinal fluid (CSF)
1. Definition: a clear watery liquid produced
in the ventricles of the brain.
Spinal cord
1. Anatomy:
a. bundle of neurons,
about 17" in length
b. made of 2 types of tissue
1) gray matter- made of nerve cell bodies,
neuroglial cells and blood vessels
2) white matter- made of axons
c. consists of 31 segmentseach segment gives rise to a pair of
spinal nerves
Draw the location of the nerve cell bodies and axons.
2. Physiology
a. conducts nerve impulses
b. serves as a center for spinal reflexes
Structures of a vertebra
Structures of the CNS
The Brain
DEFINITION:
• The part of the CNS
located within the skull
• composed of 100
billion neurons and
even more glia cells
• weighs 3 pounds
FUNCTION
primary receiver,
organizer and
distributor of
information for the
body
Can you put this in your
own words?
Spinal cord
1. Brain stem:Responsible for basic life
functions such as
•
•
•
Breathing
Heartbeat
Blood pressure
Scientists say that this is the "simplest" part
of human brains because a reptile’s
(who appear early on the evolutionary
scale) entire brain resembles our brain
stem.
2
1
Spinal cord
Thalamus
-interprets all senses except smell
-synapses for voluntary movement
Hypothalamus
-controls the autonomic nervous system
-coordinates the nervous and endocrine
systems
3
Cerebrum (7/8 of human brain)
Associated with higher brain functions such as
thought and action.
Divided into 4 lobes
How do we know what each
part of the cerebrum does?
• MRI
• Surgery
The surface of the
cerebrum is highly
folded.
Ridges = gyri
Grooves = sulci
Deep grooves=
fissures
What is the purpose
of all these folds?
Folds increase surface area.
Use the pictures to make an analogy.
Left
hemisphere
Right
hemisphere
Sometimes the right
hemisphere is associated with
creativity and the left
hemispheres is associated with
logic abilities.
The corpus callosum is
a bundle of axons which
connects these two
hemispheres.
4
Cerebellum (Little brain)
-associated with regulation and coordination of
movement, posture, and balance
1. By the time you were born you lost _____
of the neurons you had as a fetus.
A. 10%
B. 25%
C. 50%
2. As a teenager you ( lose / gain ) neurons
as your body streamlines itself for optimal
function.
3. Your brain is an energy hog. It occupies
2% of your body but uses _____ of your
energy when you are at rest.
A. 10%
C. 50%
B. 20%
D. 75%
4. The more you repeat something the more
brain space is dedicated to it. For example,
in musicians the part of the brain that
controls fingers used to play an instrument is
up to 130% larger than in a non-musician.
True or False?
5. Once you learn a task your brain shuffles
it to a lower level of consciousness to save
energy. If you move it into a conscious level
you may make a mistake. True or False?
6. Stress can shrink your brain.
True or False?