Chapter 8 Study Guide:
The Nervous System
Anatomy Bowl Prep
Organs and Divisions of the Nervous
System (understand)
• Central Nervous System (CNS)
– Brain
– Spinal Cord
• Peripheral Nervous System (PNS)
– Cranial Nerves
– Spinal Nerves
– Autonomic Nervous System (ANS): Involuntary
• Sympathetic
• Parasympathetic
CNS vs. PNS
• Two types of cells found in the nervous
system:
– Neurons and glial cells
– Neurons conduct impulses, whereas glial cells are
for support
• Each neuron consist of a cell body, dendrites,
and an axon
Nerves
• A nerve is a group of peripheral nerve axons bundled together
like the strands of a cable
• Because nerves usually have myelin sheath and myelin is
white, nerves are called white matter in the PNS
• Bundles of axons are called tracts, and may be myelinated and
thus form this system of white matter
• Dendrites is called gray matter because of its characteristic
grey appearance
• Understand that myelinated nerves have faster conduction
velocity
– Which means that they are able to carry a signal much faster than
nonmyelinated fibers
Reflex Arc
(understand concept)
• Brain is not “consciously” involved: pathway of nerve
fibers and does not ascend to communicate with the
neurons of the brain after stimulus is applied.
• Sensory (afferent) impulse
– Sensory neuron cell bodies housed in the Dorsal Root
Ganglion (DRG)
• Motor (efferent) impulse
– Motor neuron cell bodies housed in the Ventral (Anterior)
Horn of the Gray Matter of Spinal Cord
• Interneurons may be involved if the reflex arc is
“polysynaptic”
– Polysynaptic vs. Monosynaptic
Neurotransmission
(understand)
• Propagated action potential (AP) causes
release of a neurotransmitter (NT)
– Over 30 NTs identified
– NTs are docked in vesicles at the axon terminus
• NTs are released into the synaptic cleft
– Bind to complementary receptors
– Binding is either stimulatory or inhibitory to postsynaptic cell
• Post-synaptic cell is either an effector cell (skeletal
muscle or glandular cell) or another neuron
Divisions of the Brain
(structure and function)
• Cerebrum
• Diencephalon
– Thalamus
– Hypothalamus
• Cerebellum
• Brainstem
– Midbrain
– Pons
– Medulla Oblongata
Hypothalamus
Neurons here can make hormones
Medulla Oblongata
Vital centers are located here
Thalamus
This area of the brain associates
sensations with emotions
Cerebellum
This is the second largest part of the
brain
Cerebrum
This part of the brain is made up of gyri
Spinal Cord
(structure and function)
• Don’t worry about different spinothalamic tracts!!!
• Understand that grey mater is found in the center of
the spinal cord
• White mater is found around the outer portion of the
spinal cord
• Meninges: are protective tissue layers that enclose the
brain and spinal cord. The three layers are
– Dura
– Arachnoid
– Pia
• There are spaces in between the meningeal layers.
• Ex: epidural layer, sub dural layer
Clinical Applications
• Herpes Zoster or Shingles
– Is a unique viral infection that almost
always affects the skin of a single
dermatome
• A dermatome is a pathway that a
nerve travels to innervate the skin
– The result is that a patient would
experience a painful eruption of red,
swollen, plaques of vesicles on their
skin