Post on 12-Jul-2020
IV. CENTRAL NERVOUS SYSTEM (CNS):
1. Flat bones of the skull & vertebrae
A. Protective Structures of the CNS:
located along the midline of the body;
brain & spinal cord
receives sensory information and creates
a response
2. Meninges – three membranes surrounding CNS
1. dura mater – thick, tough, outer layer
2. arachnoid mater – middle layer with a web-like region
that allows fluid to circulate freely
3. pia mater – thinnest, innermost layer attached directly to
the brain & spinal cord
Pia Mater
Arachnoid
Mater
Dura
Mater
Cranial Bone
3. Cerebrospinal Fluid (CSF)
clear, lubricating fluid that bathes the CNS
acts as a cushion & provides nourishment to nervous tissue
is produced within cavities of the brain called ventricles
B. Brain – processing center composed of billions of neurons
1. Cerebrum:
largest portion of the brain
the outer portion of gray matter is
called the cerebral cortex
the wrinkles of the cerebral cortex
are called convolutions (gyri =
ridges & sulci = grooves)
divided into four regions:
frontal lobe parietal lobe
temporal lobe occipital lobe
controls memory, learning/thinking, movement, & the senses
2. Cerebellum:
inferior, posterior portion of the brain
regulates balance, posture, & muscle coordination
Cerebellum
Cerebrum
3. Brain Stem:
a. Diencephalon
i. thalamus - acts as a relay station for sensory impulses
to the brain
ii. hypothalamus - controls the autonomic (involuntary)
system to control hunger, body, temp.,
emotions, & sex drive
Thalamus
Hypothalamus
b. Midbrain
acts as a pathway for impulses between brain & spinal cord
c. Pons
connects the cerebellum to the cerebrum
d. Medulla Oblongata
connects the brain to the spinal cord and regulates heart rate,
blood pressure, respiratory rate
MEDULLA
OBLONGATA
DIENCEPHALON
PONS
MIDBRAIN
Cerebrum
Cerebellum
Brain Stem
Medulla
Oblongata
Midbrain
Pons
Diencephalon
C. Spinal Cord
extends from the brain through the vertebrae to connect the
brain with the nerves of the body
surrounded by vertebrae, the meninges, & is bathed in
cerebrospinal fluid (CSF)
V. PERIPHERAL NERVOUS SYSTEM (PNS)
1. Nerves - carry nerve impulses between CNS and skin,
muscles, glands, organs
A. Organs of the PNS:
extends from the midline to the outer portions of the body
carry information to/from the CNS
a. Types of Nerves:
i. cranial nerves – extend from the
brain to head/neck
ii. spinal nerves – extend from the
spinal cord to the
body
2. Ganglion – cluster of neuron cell bodies located outside of the CNS
3. Sensory receptors – neurons specialized to respond to stimuli such
as pressure, pain, light, chemicals, and
temperature (found in eyes, ears, nose, skin,
& tongue)