Chapter 13

Question 1

Stimulus type

Answer 1

mechanoreceptors, thermorecptors, photoreceptors, chemoreceptors, nociceptors, exteroceptors, interceptors, proprioceptors

Question 2

Sensory (afferent) nerves

Answer 2

impulses only toward CNS

Question 3

motor (efferent) nerves

Answer 3

impulses only away from CNS

Question 4

Ganglia

Answer 4

contain neuron cell bodies associated with nerves in PNS

Question 5

Ganglia associated with afferent nerve fibers

Answer 5

contain cells bodies of sensory neurons

-dorsal root ganglia

Question 6

Ganglia associated with efferent nerve fibers

Answer 6

contain autonomic motor neurons

-autonomic ganglia

Question 7

CNS axons

Answer 7

most CNS fibers can never regenerate and CNS oligodendrocytes bear growth-inhibiting proteins that prevent CNS fiber regeneration

Question 8

Form scar tissue at injury site

Answer 8

astrocytes

Question 9

CNS axons treatment

Answer 9

neutralizing growth inhibitors, blocking receptors for inhibitory proteins, destroying scar tissue components

Question 10

PNS axons

Answer 10

can regenerate if damage is not severe

Question 11

Steps of PNS axon regeneration

Answer 11

• axon fragments and myelin sheaths distal to injury degenerate, degeneration spreads down axon
• macrophages clean dead axon debris, Schwann cells are stimulated to divide
• axon filaments grow through regeneration tube
• axon regenerates, and new myelin sheath forms

Question 12

Olfactory nerves (I)

Answer 12

purely sensory (olfactory) function

Question 13

Optic nerves (II)

Answer 13

purely sensory (visual) function

Question 14

Oculomotor nerves (III)

Answer 14

function in raising eyelid, directing eyeball, constricting iris (parasympathetic), and controlling lens shape

Question 15

Trochlear nerves (IV)

Answer 15

primarily motor nerve that directs eyeball

Question 16

Trigeminal nerves (V)

Answer 16

convey sensory impulses from various areas of face (V1 and V2)
supply motor fibers for mastication (V3)

Question 17

Abducens nerves (VI)

Answer 17

serves the lateral rectus eye muscle

Question 18

Facial nerves (VII)

Answer 18

motor functions include facial expressions, parasympathetic impulses to lacrimal and salivary glands and sensory function (taste) from anterior two-thirds of tongue

Question 19

Vestibulocochlear nerves (VIII)

Answer 19

hearing and equilibrium

Question 20

Glosspharyngeal nerves (IX)

Answer 20

motor functions: innervate part of tongue and pharynx for swallowing and provide parasympathetic fibers to parotid salivary glands
sensory functions: fibers conduct taste and general sensory impulses from pharynx and posterior tongue, and impulses from carotid chemoreceptors and baroreceptors

Question 21

Vagus nerves (X)

Answer 21

most motor fibers are parasympathetic fibers that help regulate activities of heart, lungs, and abdominal viscera

Question 22

Accessory nerves (XI)

Answer 22

accessory nerves exit skull via jugular foramina to innervate trapezius and sternocleidomastoid muscles

Question 23

Hypoglossal nerves (XII)

Answer 23

innervate extrinsic and intrinsic muscles of tongue that contribute to swallowing and speech

Question 24

Pairs of cervical nerves

Answer 24

8 pairs

Question 25

Pairs of thoracic nerves

Answer 25

12 pairs

Question 26

Pairs of lumbar nerves

Answer 26

5 pairs

Question 27

Pairs of sacral nerves

Answer 27

5 pairs

Question 28

Pairs of tiny coccygeal nerves

Answer 28

1 pair

Question 29

Phrenic nerve

Answer 29

major motor and sensory nerve diaphragm, major muscles for breathing

Question 30

Components of reflex arc

Answer 30

• receptor
• sensory (afferent) neuron
• integration center
• motor (efferent) neuron
• effector