Chapter 13

Question 1

The PNS detects …………. stimuli and delivers the information to the CNS as sensory input.

Answer 1

sensory

Question 2

The CNS processes the input and transmits the impulse through the PNS to …………. cells and …………… as motor output.

Answer 2

muscle cells and glands

Question 3

Summarize the function of the somatic sensory division.

Answer 3

detects stimuli of both general and special senses and sends it to CNS

Question 4

Summarize the function of the visceral sensory division.

Answer 4

relays sensory info from organs in the abdominopelvic and thoracic cavities to the CNS

Question 5

The sensory division consists of ………… neurons, whereas the motor division consists of ………….. neurons

Answer 5

afferent, efferent

Question 6

Generalize the function of the somatic motor division.

Answer 6

stimulate skeletal muscle contractions

Question 7

Generalize the function of the visceral motor division (autonomic motor nervous system, ANS).

Answer 7

maintains homeostasis by controlling involuntary function. Stimulates cardiac and smooth muscle.

Question 8

What is the sympathetic nervous system of the ANS (fight or flight division) involved in?

Answer 8

maintains homeostasis when the body is involved in any type of work. Mediates visceral responses to emotion.

Question 9

What is the parasympathetic system of the ANS (rest and digest division) involved in?

Answer 9

digestion and maintaining homeostasis when body is at rest

Question 10

What do mixed nerves contain?

Answer 10

both sensory and motor neurons

Question 11

Sensory nerves contain only ………….. neurons, while motor nerves contain mostly motor neurons and some …………… neurons involved in muscle stretch and tension.

Answer 11

sensory, sensory

Question 12

Two collections of axons connect the PNS with the spinal cord’s gray matter: the anterior root consists of ……….. neurons from the anterior horn, and the posterior root consists of ………….. neurons from the posterior horn.

Answer 12

motor, sensory

Question 13

How many pairs of spinal roots are there? True or false, they are all mixed nerves.

Answer 13

31, true

Question 14

What is the function of the epineurium? What is the function of the perineurium? What is the function of the endoneurium?

Answer 14

1. binds bundles of fascicles into one spinal nerve
2. binds individual fascicles
3. binds the axons within a fascicle

Question 15

spinal nerves are formed by the fusion of ?

Answer 15

anterior and posterior roots

Question 16

The spinal nerve is short and divides into the following two mixed nerves ……….. and ………….

Answer 16

anterior ramus and posterior ramus

Question 17

Thirty-one pairs of spinal nerves consist of ………. pairs of cervical nerves, ………….. pairs of thoracic nerves, ………….. pairs each of lumbar and sacral nerves, and one pair of coccygeal nerves.

Answer 17

8, 12, 5

Question 18

The anterior rami of the cervical, lumbar, and sacral spinal nerves each merge to form complicated networks of nerves called

Answer 18

nerve plexuses

Question 19

What do the branches of the cervical plexus serve?

Answer 19

sensory to the skin of chest, shoulder and ear, and motor to diaphragm and swallowing muscles

Question 20

the phrenic nerve innervates the …….

Answer 20

diaphragm

Question 21

Do Thoracic Spinal Nerves form plexuses?

Answer 21

no, except for T-1

Question 22

What do nerve branches from the Lumbar plexuses innervate?

Answer 22

mainly the pelvis and lower extremity

Question 23

The …………… nerve, the longest and largest nerve in the body, contains axons from both the anterior and posterior divisions of the sacral plexus. It travels through the greater sciatic notch in the pelvis into the thigh, passing between the greater trochanter and the ischial tuberosity. What does this nerve innervate?

Answer 23

sciatic, the hip joint, feeds into the fibular and tibial nerves

Question 24

What are the 5 major nerves of the brachioplexus?

Answer 24

1. Axillary
2. Radial
3. Musculocutaneous
4. Median
5. Ulnar

Question 25

The anterior division of the Lumbar plexus’s largest member is the ……………… which enters the thigh from the pelvis via the obturator foramen. What do branches of this nerve innervate?

Answer 25

Obturator nerve. Adductors, hip joint and inner thigh skin

Question 26

The posterior division of the Lumbar plexus’s largest member, the ……….. nerve, is the largest branch of the lumbar plexus. This nerve travel from the psoas, through the pelvis and under the inguinal ligament to enter the thigh. What does this nerve innervate?

Answer 26

Femoral nerve, Quads, knee, and skin of thigh

Question 27

What do nerve branches from the Sacral plexus innervate?

Answer 27

pelvis, gluteal region, and much of the lower extremity.

Question 28

What do the branches of the tibial nerve innervate?

Answer 28

hamstrings, knee, gastroc, ankle, and plantar flexor muscles

Question 29

What does the common fibular nerve and its branches innervate?

Answer 29

knee and distal leg

Question 30

Rapidly adapting receptors respond rapidly with high intensity to stimuli but stop sending signals after a certain time period, called ………………. These receptors detect the initiation of stimuli but ignore ongoing stimuli.

Answer 30

adaptation

Question 31

What type of adapting receptors respond to stimuli with constant action potentials that don’t diminish over time.

Answer 31

slowly adapting receptors

Question 32

Sensory receptors exist in many forms; some called ……….. nerve endings are surrounded by specialized supportive cells while others, called …………. nerve endings, lack supportive cells.

Answer 32

encapsulated, free

Question 33

where are exteroceptors located, and what do they detect?

Answer 33

close to surface of body, and detect stimuli originating from outside of body like texture, temp, color, smell, level of light

Question 34

where are interoceptors located, and what do they detect?

Answer 34

body’s interior, and detect, stimuli originating from within the body like blood pressure, body temp, stretch of organs, and concentration of chemicals

Question 35

……………. are encapsulated interoceptors or exteroceptors found in the musculoskeletal system, skin, and in many other organs. What causes them to depolarize?

Answer 35

mechanoreceptors, in response to anything that mechanically deforms the cell

Question 36

………. are exteroceptors, most of which are slowly adapting receptors. What causes them to depolarize?

Answer 36

thermoceptors, temperature changes

Question 37

…………….. can be either interoceptors or exteroceptors that are capable of binding to specific chemicals that, once bound, generate a receptor potential as sodium ion channels open. What causes them to depolarize?

Answer 37

chemoreceptors, chemicals binding to their specific receptors

Question 38

…………… are special sensory exteroceptors found only in the eye. What causes them to depolarize?

Answer 38

Photoreceptors, light

Question 39

………… are usually slowly adapting exteroceptors that detect noxious stimuli translated to pain. What causes nociceptors to depolarize?

Answer 39

Nociceptors, noxious stimuli

Question 40

What are the six classes of mechanoreceptors?

Answer 40

1. Merkel Cells: (fingertips) discriminitive touch
2. Tactile corpuscles: (very numerous) discriminative touch, but less refined
3. Ruffini Endings: (ligaments) stretch/movement
4. Lamellated corpuscles: (onion shape) vibrations
5. Hair follicle receptors: stimuli that makes hair bend
6. Proprioceptors: sense position in space

Question 41

Structure of sensory neurons: Somatic sensory neurons are pseudounipolar neurons with the following three main components:
a. The ………………. is located in the posterior root (or dorsal root) ganglion, just lateral to the spinal cord.

b. The peripheral process of the neuron is a long …………… that transmits action potentials from the source of the stimulus (a receptor) to the neuron’s central process.
c. The central process exits the cell body and travels through the posterior root to enter the spinal cord at the posterior horn (or the brainstem for cranial nerves) where they deliver their action potentials.

Answer 41

cell body, axon

Question 42

Large diameter axons with thick myelin sheaths conduct the …………… impulses. What types of axons fall into this category?

Answer 42

Fastest. Proprioceptive, discriminate and nondiscriminate touch

Question 43

Small diameter axons with little myelin transmit action potentials the ………….. What types of axons fall into this category?

Answer 43

Slowest. axons that transmit pain and temperature stimuli

Question 44

What is a Receptive field?

Answer 44

The area served by a neuron. The more branches a neuron possesses the larger that neuron’s receptive field

Question 45

Body regions whose primary function is sensing the environment contain many neurons with smaller receptive fields. Provide an example of a body region with a small receptive field:

Answer 45

fingertips

Question 46

Body regions that are not as involved in sensing the environment have fewer neurons with larger receptive fields. Provide an example of a body region with a large receptive field:

Answer 46

forearm or back

Question 47

………….. is a method for measuring the relative size of receptive fields

Answer 47

two point discrimination threshold

Question 48

What is a dermatome, and Why are dermatome maps used clinically?

Answer 48

Area of skin that is determined by the spinal nerve that serves it. To test the integrity of sensory pathways to different parts of the body.

Question 49

Why does referred pain occur?

Answer 49

spinal nerves carry both somatic and visceral neurons. So visceral sensations travel along the same path as somatic sensations. Therefore, visceral pain can be perceived in different ares than where it originates.