chapter 3

Question 1

what are the two Structure of the nervous system

Answer 1

	CNS
	Spinal cord
	Brain
	PNS
	Spinal nerves and branches 
	Cranial nerves

Question 2

CNS structure

Answer 2

 Spinal cord

 Brain

Question 3

PNS structure

Answer 3

 Spinal nerves and branches

 Cranial nerves

Question 4

C2 – C8

Answer 4

7 Cervical Dermatomes (C2 – C8)

Question 5

T1 – T12

Answer 5

12 Thoracic Dermatomes (T1 – T12)

Question 6

L1 – L5

Answer 6

5 Lumbar Dermatomes (L1 – L5)

Question 7

S1 – S5

Answer 7

5 Sacral Dermatomes

Question 8

The spinal nerves

are named for

Answer 8

the level
of the spinal cord from 
which they exit and 
are numbered from
top to bottom

Question 9

C1 CERVICAL is different because

Answer 9

it has nothing to do with the dermatomes The C1 nerve innervates the meninges and has no cutaneous branch

Question 10

Neural tissues are composed of two major classes of cells

Answer 10

• Glial Cells

- Neurons

Question 11

Glial Cells

Answer 11

-connective tissue ( also known as glue )
-Glial cells were traditionally viewed as the glue that holds the neuronal system together
but
-Glial cells and neurons enjoy a far more balanced sharing of nervous system functions

Question 12

Provide nutrients and oxygen to neurons
Help maintain homeostasis
> Regulate the internal environment of the brain
> Especially regulate the fluid surrounding neurons and synapses
Provide electrical insulation
> Wrap themselves around axons of neurons (myelin sheath)

Answer 12

Functions of Glial Cells

Question 13

Destroy pathogens
> Serve as resident macrophage-like cells
Regulate neuronal repair
> Especially after physical trauma or injury due to virus infection
> Within the CNS, glia suppress neuronal repair, whereas …
> Within the PNS, glia promote neuronal repair
Regulate removal of dead neurons

Answer 13

Glial Cells

Question 14

in function of does glia cells Within the CNS, glia ———-

Answer 14

suppress neuronal repair

Question 15

in function of does glia cells Within the PNS, glia ———-

Answer 15

promote neuronal repair

Question 16

what is the difference between neurons and glial cells

Answer 16

neurons are the ability of neurons to generate action potentials and the polarity of neurons (axons and dendrites) that glial cells lack

Question 17

what are the types of glial cells

Answer 17

Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
Schwann cells
Satellite cells

Question 18

What is the most abudant type of glial cell in CNS

Answer 18

Astrocytes

Question 19

What are the two layers of astrocytes

Answer 19

>

Protoplasmic:	Short, thick, highly branched processes Gray matter Fibrous:	Long, thin, less branched processes White matter

Question 20

Oligodendrocytes

Myelin sheath provides ———- to axon of the neuron which enhances efficiency of electrical signal propagation along the axon

Answer 20

insulation

Question 21

Oligodendrocytes

Answer 21

Cells that coat axons of neurons in the CNS with their cell membrane, called myelin

Question 22

A fatty covering that envelopes many axons and permits action potentials to be propagated at much greater velocity

Answer 22

Myelin

Question 23

myelin is Not part of, nor produced by

Answer 23

neurons

Question 24

Myelin is formed by

Answer 24

Formed by oligodendrocytes in CNS and Schwann cells in PNS wrapping around axons

Question 25

• Not technically glia but derived from hemopoietic precursors as are blood monocytes
• Specialized macrophages, capable of phagocytosis to protect neurons
• Found in all regions of the brain / spinal cord
• Relatively small with changing shapes and oblong nuclei
• Mobile within the brain and multiply when brain is damaged
• During health, they constantly sample all aspects of the CNS microenvironment (neurons, other glial cells, blood vessels)
• During brain damage or disease, play an important role in inflammation

Answer 25

Microglia

Question 26

• Form the surface layer of the wall of the system of interconnected, fluid-filled cavities of the brain (ventricles) and spinal cord (central canal)
• Create and secrete cerebrospinal fluid and help circulate it via cili

Answer 26

Ependymal Cells

Question 27

Schwann Cells

Answer 27

-Similar in function to oligodendrocytes of the CNS

• Provide myelination to axons on neurons of the PNS
• They also exhibit phagocytotic activity and clear cellular debris in support of the regrowth of PNS neurons

Question 28

Satellite Cells

Answer 28

• Small cells that surround neurons in sensory, sympathetic, and parasympathetic ganglia
• Help regulate the external chemical environment
• Similar to astrocytes in the CNS
• Highly sensitive to injury and inflammation and contribute to pathologic conditions such as chronic pain

Question 29

Cellularity:

Answer 29

The neuron is the fundamental structural and functional element of the brain

Question 30

Synaptic communication

Answer 30

The terminals of one neuron’s axon communicate with the dendrites of another neuron only at specialized sites (synapses)

Question 31

Connection specificity

Answer 31

Neurons form synapses and communicate with certain neurons and not with others (neurons do not form connections indiscriminately)

Question 32

Dynamic polarization

Answer 32

Signals in a neural circuit travel in only one direction (dendrites to cell body to axon to presynaptic terminal and then across the synaptic cleft)

Question 33

A typical cell body contains only a fraction of total cell volume, the rest found in axon and dendrites

Answer 33

Cell Body (Soma)