Transcript The Nervous System Chapter 8

The Nervous System
- Lab Exercise 5
Divisions of the Nervous
System
 Central nervous system (CNS) –
brain & spinal cord
 Peripheral nervous system (PNS) –
cranial nerves & spinal nerves
The Central Nervous System
CNS well protected by bones (cranial & vertebrae),
CT meninges, & cerebrospinal fluid (CSF)
Meninges – Connective tissues that surround
and protect the brain and spinal cord (CNS)
3 layers:
• Dura Mater
• Arachnoid
• Pia Mater
Meninges
Dura Mater – tough,
fibrous outer layer
 2 layers thick around
brain with creation of
dural sinuses between
layers;
 1 layer around
spinal cord with
epidural space
external
Meninges
Arachnoid – “spidery” web-like middle layer
Pia Mater – delicate, thin inner layer;
adhered to brain & cord; extension of pia
mater (“filum terminale”) extends from tip of
cord to coccyx to anchor cord in place
Subarachnoid space – between arachnoid & pia
mater; contains cerebral spinal fluid (CSF)
Superior sagittal sinus
Dura mater
(gray color)
Arachnoid (orange color)
Subarachnoid space (blue color)
Pia mater (red color)
The Brain
 Brain stem
 medulla oblongata (M.O.)
Cerebrum
 pons
 midbrain
 Diencephalon
T
H
M
 thalamus
PP
 hypothalamus
midbrain
Cerebellum
 mamillary bodies
 epithalamus (pineal gland)
pons
m.o.
 Cerebrum
 Cerebellum
Cerebrum
P
T
H
M
pons
Cerebellum
m.o
Spinal cord
The Brainstem
 medulla oblongata (M.O.)
 pons
 midbrain –
 cerebral peduncle
 cerebral aqueduct of
midbrain
 corpora
quadrigemina
pons
 superior colliculi
Cerebral
peduncle
Cerebral
aqueduct of
midbrain
m.o.
 inferior colliculi
Cerebral aqueduct of
midbrain
Superior colliculus
Inferior
colliculus
Cerebral peduncle
The Diencephalon
 thalamus
 intermediate
mass
Intermediate mass
of thalamus
 hypothalamus
P
 mamillary bodies
T
H
 connects to
pituitary gland via
infundibulum
M
Pituitary
gland
infundibulum
 epithalamus (pineal
gland)
Cerebrum
convolutions
gyrus
sulcus
4 lobes per hemispherefrontal, parietal,
temporal, occipital
The Cerebrum
corpus callosum
septum
pellucidum
fornix
The Cerebellum
 gray matter “folia”
 white matter “arbor
vitae”
 separated from
cerebrum by transverse
fissure
Transverse
fissure
Cerebrospinal Fluid (CSF)
clear, colorless fluid formed by filtration of blood
plasma by choroid plexuses within ventricles of the
brain.
 functions in protection of CNS, support, nutrient
supply, waste removal
CSF Circulation
Lateral ventricle (behind
septum pellucidum)
Third ventricle
Aqueduct
of midbrain
Fourth ventricle
Lateral ventricles (in
cerebral hemispheres) 
interventricular foramen
 third ventricle (in
diencephalon around
thalamus)  cerebral
aqueduct of midbrain 
fourth ventricle (between
pons/cerebellum) 
subarachnoid space &
central canal of SC
Reabsorption of CSF through
arachnoid granulations (arachnoid
villi) of dural sinuses (superior
sagittal sinus)  into cerebral veins
Superior sagittal
sinus
Arachnoid
granulation
(villus)
Cranial Nerves
 12 pairs of nerves that connect to the brain; provide
motor, sensory &/or autonomic (parasympathetic)
function
I (olfactory bulb)
Olfactory tract
Optic chiasm
Optic tract
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VI VII
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