Chapter 11

Question 1

Functions of Nervous System

Answer 1

• sensory input
• integration
• motor output

Question 2

Motor Output

Answer 2

activation of effector organs (muscles and glands) produces a response

Question 3

Sensory (afferent) division

Answer 3

somatic and visceral sensory fibers

Question 4

Somatic sensory fibers

Answer 4

convey impulses from skin, skeletal muscles, and joints to CNS

Question 5

Visceral sensory fibers

Answer 5

convey impulses from visceral organs to CNS

Question 6

PNS

Answer 6

sensory and motor

Question 7

Motor (efferent)

Answer 7

transmits impulses from CNS to effector organs

-muscles and glands

Question 8

Neuroglia (glial cells)

Answer 8

small cells that surround and wrap delicate neurons

Question 9

Neurons (nerve cells)

Answer 9

excitable cells that transmit electrical signals

Question 10

Astrocytes

Answer 10

most abundant, versatile, and highly branched of glial cell

Question 11

Astrocytes function

Answer 11

support and brace neurons

Question 12

Microglial cells

Answer 12

can transform to phagocytize microorganisms and neuronal debris

Question 13

Ependymal cells

Answer 13

line the CSF-filled ventricles in the brain and the central canal of the spinal cord

Question 14

Oligodendrocytes

Answer 14

processes wrap CNS nerve fibers, forming insulating myelin sheaths in thicker nerve fibers

Question 15

Schwann cells

Answer 15

similar function as oligodendrocytes but in PNS

Question 16

Where are most neuron cell bodies located?

Answer 16

CNS

Question 17

nuclei

Answer 17

cluster of neuron cell bodies in CNS

Question 18

ganglia

Answer 18

clusters of neuron cell bodies in PNS

Question 19

Myelination in the PNS

Answer 19

formed by Schwann cells

Question 20

Schwann cells

Answer 20

wraps around axon in jelly roll fashion and one cell forms one segment of myelin sheath

Question 21

Myelin sheaths in the CNS

Answer 21

formed by processes of oligodendrocytes

Question 22

Functional classification of neurons

Answer 22

sensory, motor, interneurons

Question 23

Na+ channel inactivation gates close

Answer 23

membrane permeability to Na+ declines to resting state and AP spike stops rising

Question 24

Repolarization

Answer 24

membrane returns to resting membrane potential

Question 25

Hyperpolarization

Answer 25

some K+ channels remain open, and Na+ channels reset

Question 26

Saltatory conduction

Answer 26

occurs only in myelinated axons and is about 30 times faster

Question 27

Myelinated axons

Answer 27

• myelin sheaths insulate and prevent leakage of charge
• voltage-gated Na+ channels are located at myelin sheath gaps
• APs generated only at gaps
• electrical signal appears to jump rapidly from gap to gap