Anatomy & Physiology
Part 2: Nervous System
The Brain:
• ~100 billion multipolar neurons
• 3 major components:
– The cerebrum largest part (associated with
sensory & motor functions, higher mental
functions)
– The cerebellum (voluntary muscle movement &
coordination)
– The brain stem (connects & regulates viscera)
Another part of the brain is the diencephalon. This is
also associated with sensory functions.
http://www.google.com/imgres
Cerebrum:
• There are 2 cerebral
hemispheres. This is
collectively called
the cerebrum.
• Gyri are ridges;
sulci are grooves.
• Fissures are deep
grooves
– Fissures divide the
cerebrum into lobes.
http://www.google.com/imgres
Cerebrum Lobes:
These are named for the bones they
are under.
1.
2.
3.
4.
5.
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Insula
• The corpus callosum is a “bridge” of
nerve fibers that connect the 2
hemispheres.
• The hemispheres generally mirror each
other.
There are 3 main areas of the
cerebrum:
• Cerebral Cortex
• White Matter
• Basal Nuclei
Cerebrum: Cerebral Cortex:
• Functions: speech, memory, logic,
emotional responses, & voluntary
movement
The cortex includes:
• Broca’s area: vocalization/formation
of words
• Speech area: language
comprehension (meanings of words)
http://www.google.com/imgres
Cerebrum:
White Matter:
Basal Nuclei:
• Contains nerve tracts
that allow
communication to occur
between hemispheres
and brain stem
• a.k.a. basal ganglia
• Gray matter
• Regulate voluntary
motor functions
Diencephalon:
• It contains the thalamus,
hypothalamus, optic tracts
pituitary gland, mammillary
gland & pineal gland.
• The thalamus is the central
region of message relays;
receiving all sensory info
(except smell) &
transmitting the signals to
the appropriate location.
– It produces awareness of
sensations.
http://www.google.com/imgres
• The hypothalamus maintains
homeostasis & links the NS to the
endocrine system. It regulates:
– Heart rate & blood pressure
– Body temperature
– Water & electrolyte balance
– Hunger & body weight
– Stomach & intestinal secretions & movement
– Sleep & wakefulness
– Production of stimulants for the pituitary gland
Diencephalon:
• The hypothalamus
includes the limbic
system and
controls emotional
responses &
expression; as a
result, it guides
behavior to
increase the
chance of survival.
Other glands part of
the Diencephalon:
• Pituitary gland
(hormones)
• Pineal gland (sleep
regulation)
• Choroid plexuses
(capillaries that
secrete CSF)
Brain Stem:
• Connects the spinal
cord to the cerebrum
Midbrain
• Includes the midbrain,
pons & medulla
oblongata
• The midbrain contains
reflex centers (visual
& auditory
http://www.google.com/imgres
• The pons is
between stem &
oblongata; relays
sensory impulses
& regulates rate &
depth of breath.
• The medulla
oblongata is below
the pons
• The medulla
oblongata is
associated with
coughing,
sneezing,
swallowing &
vomiting reflexes.
• It controls heart
rate, blood
pressure, and
breathing
• The reticular formation is a network
of nerve fibers that are throughout
the midbrain, pons & medulla
oblongata.
• This regulates wakefulness (increased
activity increases awareness;
decreased activity induces sleep).
• If this is injured, this causes
unconsciousness; if the person
cannot be aroused, a comatose state
(coma) results.
Cerebellum:
• Integrates & coordinates sensory
info & skeletal muscles; helps to
maintain posture.
• Injury to this area will cause tremors
(involuntary movements), inaccurate
movements, staggering walk, muscle
tone loss or equilibrium disturbance.
Protection of CNS: Meninges
• The CNS is surrounded by bones,
membranes & fluids (skull contains the
cranial cavity which contains the brain, etc.).
• The membranes of the CNS are the
meninges (between bones & soft tissues).
• These protect the brain & spinal cord.
• There are 3 layers to the meninges: dura
mater, arachnoid mater, & pia mater.
http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19080.jpg
Meninges:
Dura Mater:
Arachnoid Mater:
•
outermost layer
•
•
found within the
cranial cavity,
surrounds skull
bones, & extends
inward between brain
lobes
Thin membrane
without a blood
supply
•
Between dura mater &
pia mater
•
Covers brain & spinal
cord
•
Surrounds the spinal
cord & ends as a sac
right below the cord
(but is not attached to
the vertebrate).
•
Between the
arachnoid mater
& pia mater is the
subarachnoid
space. The
cerebrospinal
fluid (CSF) is
contained here.
–
This is a clear
watery fluid that
bathes the brain &
spinal cord.
Pia Mater:
• The innermost
layer of the
meninges
•
Covers the brain
& spinal cord and
follows their
surfaces closely
Spinal Cord:
• This is a nerve column that
goes from the brain into
the vertebral canal.
• Consists of 31 segments &
31 pairs of spinal nerves
• There are 2 enlargements:
the cervical enlargement
contains the nerves for the
upper limbs; the lumbar
enlargement contains the
nerves for the lower limbs.
http://www.google.com/imgres
Spinal Cord with Meninges:
http://www.google.com/imgres
PNS: Cranial Nerves:
• There are 12 pairs of cranial nerves:
1. Olfactory nerves (I): sense of smell
2. Optic nerves(II): vision (eyes to brain)
3. Oculomotor nerves (III): eye muscle
movement (somatic & autonomic)
4. Trochlear nerves (IV): eye movement;
smallest cranial nerves
5. Trigeminal nerves (V): contain ophthalmic,
maxillary, & mandibular nerves; mixed nerves;
largest cranial nerves.
6. Abducens nerves (VI): aids in eye muscle movement
7. Facial nerves (VII): taste receptors; stimulate
salivary & tear gland secretions (autonomic)
8. Vestibulocochlear nerves (VIII): maintain equilibrium
& enable hearing (ear)
9. Glossopharyngeal nerves (IX): swallowing; mixed
nerves; associated with the tongue & pharynx.
10. Vagus nerves (X): speech & swallowing; mixed
(autonomic & somatic)
11. Accessory nerves (XI): cranial & spinal
12. Hypoglossal nerves (XII): tongue, speaking,
chewing & swallowing.
See textbook for summary of cranial nerves.
PNS: Spinal Nerves:
•
Come from the spinal cord
•
Grouped according to their location:
1. Cervical nerves (#C1 to C8): 8 pairs
2. Thoracic nerves (#T1 to T12): 12 pairs
3. Lumbar nerves (#L1 to L5): 5 pairs
4. Sacral nerves (#S1 to S5): 5 pairs
5. Coccygeal nerves (Co): 1 pair
• See textbook summary of these spinal nerves.
Autonomic Nervous System:
• Functions independently (autonomous),
meaning without conscious thought
• Controls visceral functions
• Contains the parasympathetic &
sympathetic divisions
• The parasympathetic division functions
during restful conditions while the
sympathetic division functions during
emergency, stressful & energy spending
situations.
• Look up in text or online!
• Know the following:
Huntington’s Disease, Parkinson’s Disease,
Ataxia, Meningitis, Encephalitis,
Hydrocephalus, Blood brain barrier,
Concussion, Contusion, Intracranial
hemorrhage, cerebral edema, CVA,
hemiplegia, TIA, Cerebral palsy, Spina
bifida, and Senility
•
•
This slide show was developed by Dana Halloran,
Cardinal Mooney High School, Sarasota, FL.
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•
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Used with her personal permission,
adapted and amended by Rosa Whiting,
Manatee School for the Arts, Palmetto, FL.