chapter 13

Question 1

PNS

Answer 1

all neural structures outside the brain and
spinal cord
Provides links to and from the external
environment-(the Brain)

Question 2

Mechanoreceptors

Answer 2

respond to touch, pressure,
vibration, stretch, and itch

Question 3

Thermoreceptors

Answer 3

sensitive to changes in
temperature

Question 4

Photoreceptors

Answer 4

respond to light energy (e.g.,
retina)

Question 5

Chemoreceptors

Answer 5

respond to chemicals (e.g.,
smell, taste, changes in blood chemistry)

Question 6

Nociceptors

Answer 6

sensitive to pain-causing stimuli

Question 7

Exteroceptors

Answer 7

Respond to stimuli arising outside the body
Sensitive to touch, pressure, pain, and
temperature

Question 8

: Interceptors

Answer 8

Respond to stimuli arising within the body
Sensitive to chemical changes, stretch, and temperature changes (relays messages to the brain)

Question 9

Proprioceptors

Answer 9

Respond to degree of stretch. Found in skeletal muscles, tendons, joints,
ligaments, and connective tissue coverings of
bones and muscles

Question 10

Receptor Classification by Structural
Complexity

Answer 10

Receptors are structurally classified as either simple or complex
encapsulated and unencapsulated varieties

Question 11

Unencapsulated

Answer 11

Free dendritic nerve endings
Merkel (tactile) discs
Hair follicle receptors

Question 12

: Encapsulated

Answer 12

Meissner’s corpuscles
Pacinian corpuscles
Muscle spindles, Golgi tendon organs, and
Ruffini’s corpuscles

Question 13

Sensation to Perception

Answer 13

sense information then perceive that information

Question 14

Organization of the Somatosensory System

Answer 14

Input comes from exteroceptors,
proprioceptors, and interoceptors

Question 15

three main levels of neural integration in
the somatosensory system are:

Answer 15

Receptor level – the sensor receptors
Circuit level – ascending pathways
Perceptual level – neuronal circuits in the cerebral
cortex

Question 16

Processing at the Receptor Level

Answer 16

The receptor must have specificity for the
stimulus energy
Stimulus energy must be converted into a
graded potential

Question 17

Adaptation of Sensory Receptors

Answer 17

Adaptation occurs when sensory receptors are
subjected to an unchanging stimulus

Question 18

Receptors responding to pressure, touch, and smell

Answer 18

adapt quickly

Question 19

Receptors responding slowly include Merkel’s discs, Ruffini’s corpuscles

Answer 19

adapt slowly

Question 20

Pain receptors and proprioceptors do not exhibit adaptation

Answer 20

not at all

Question 21

Processing at the Circuit Level

Answer 21

Chains of three neurons conduct sensory
impulses upward to the brain

Question 22

First-order neurons

Answer 22

soma reside in dorsal
root, and conduct impulses from the skin to the
spinal cord

Question 23

Second-order neurons

Answer 23

soma reside in the
dorsal horn of the spinal cord and transmit
impulses to the thalamus

Question 24

Third-order neurons

Answer 24

located in the thalamus
and conduct impulses to the cortex of the
cerebrum

Question 25

Perceptual detection

Answer 25

detecting that a stimulus has occurred and requires summation

Question 26

Magnitude estimation

Answer 26

how much of a stimulus is acting

Question 27

Spatial discrimination

Answer 27

identifying the site or pattern of the stimulus

Question 28

Feature abstraction

Answer 28

used to identify a substance that has specific texture or shap

Question 29

Quality discrimination

Answer 29

the ability to identify submodalities of a sensation (e.g., sweet or sour tastes)

Question 30

Pattern recognition

Answer 30

ability to recognize patterns in stimuli (e.g., melody, familiar face)

Question 31

Regeneration of Nerve Fibers

Answer 31

Damage to nerve tissue is serious because mature neurons are amitotic If the soma of a damaged nerve remains intact, damage can be repaired

Question 32

Regeneration involves coordinated activity among

Answer 32

Macrophages – remove debris  Schwann cells – form regeneration tube and secrete growth factors  Axons – regenerate damaged part

Question 33

Regeneration of Nerve Fibers

Answer 33

damage macrophage shwan cells regeneration tube axon rootlets new axon new myelin sheath

Question 34

Cranial Nerves

Answer 34

Twelve pairs of cranial nerves arise from the brain  They have sensory, motor, or both functions  Each nerve is identified by a number (I through XII) and a name

Question 35

Ventral roots

Answer 35

arise from the anterior horn and contain motor (efferent) fibers

Question 36

Dorsal roots

Answer 36

arise from sensory neurons in the dorsal root ganglion and contain sensory (afferent) fibers

Question 37

Plexuses

Answer 37

are found in the cervical, brachial, lumbar, and sacral regions

Question 38

Cervical Plexus

Answer 38

The cervical plexus is formed by C1 -C4 The most important nerve of this plexus is the phrenic nerve  The phrenic nerve is the major motor and sensory nerve of the diaphragm

Question 39

Brachial Plexus

Answer 39

Formed by C5 -C8 and T1

Question 40

Roots

Answer 40

Roots – five ventral rami (C5 -T1)

Question 41

Trunks

Answer 41

upper, middle, and lower, which form divisions

Question 42

Divisions

Answer 42

anterior and posterior serve the front and back of the limb

Question 43

Cords

Answer 43

lateral, medial, and posterior fiber bundles

Question 44

Axillary

Answer 44

innervates the deltoid and teres minor

Question 45

Musculocutaneous

Answer 45

sends fibers to the biceps brachii and brachialis

Question 46

Median

Answer 46

branches to most of the flexor muscles of arm

Question 47

Ulnar

Answer 47

supplies the flexor carpi ulnar is and part of the flexor digitorum profundus

Question 48

Radial

Answer 48

innervates essentially all extensor muscles

Question 49

Lumbar Plexus

Answer 49

Arises from L1 -L4 The major nerves are the femoral and the obturator

Question 50

Sacral Plexus

Answer 50

Arises from L4 -S4 The major nerve is the sciatic, the longest and thickest nerve of the body

Question 51

Dermatomes

Answer 51

A dermatome is the area of skin innervated by the cutaneous branches of a single spinal nerve