13. The Peripheral Nervous System

The larger the receptive field, the

(a) Larger the stimulus needed to stimulate a sensory receptor

(b) Fewer sensory receptors there are

(c) Harder it is to locate the exact point of stimulation

(d) Larger the area of the somatosensory cortex in the brain that deals with the area

(e) Closer together the receptor cells

_______ receptors are normally inactive, but become active for a short time whenever there is a change in the modality that they monitor.

Match the receptor type in column B to the correct description in column A.

Column A

______    (1) Pain, itch, and temperature receptors

______    (2) Contains intrafusal fibers and anulospiral and flower spray endings

______    (3) Discriminative touch receptor in hairless skin (fingertips)

______    (4) Contains receptor endings wrapped around thick collagen bundles

______    (5) Rapidly adapting deep-pressure receptor

______    (6) Slowly adapting deep-pressure receptor

Column B

a. Bulbous corpuscles

b. Tendon organ

c. Muscle spindle

d. Free nerve endings

e. Lamellar corpuscle

f. Tactile corpuscle

The CNS interprets information entirely on the basis of the

(a) Number of action potentials that it receives

(b) Kind of action potentials that it receives

(c) Line over which sensory information arrives

(d) Intensity of the sensory stimulus

(e) Number of sensory receptors that are stimulated

Identify six types of tactile receptors located in the skin, and describe their sensitivities.

What three types of mechanoreceptors respond to stretching, compression, twisting, or other distortions of their plasma membrane?

What three steps are necessary for transduction to occur?

All of the following descriptions refer to dorsal column–medial lemniscal ascending pathways except one:

a. They include the fasciculus gracilis and fasciculus cuneatus.

b. They include a chain of three neurons.

c. Their connections are diffuse and poorly localized.

d. They are concerned with precise transmission of one or a few related types of sensory input.

Differentiate between a tonic receptor and a phasic receptor.

Differentiate clearly between sensation and perception.

Characterize each receptor activity described below by choosing the appropriate letter and number(s) from keys A and B. 

_____    , _____  (1) You are enjoying an ice cream cone. 

_____    , _____  (2) You have just scalded yourself with hot coffee. 

_____    , _____  (3) The retinas of your eyes are stimulated. 

_____    , _____  (4) You bump (lightly) into someone. 

_____    , _____  (5) You are in a completely dark room and reaching toward the light switch. 

_____    , _____  (6) You feel uncomfortable after a large meal.

Key A:

a. Exteroceptor

b. Interoceptor

c. Proprioceptor

Key B:

(1) Chemoreceptor

(2) Mechanoreceptor

(3) Nociceptor

(4) Photoreceptor

(5) Thermoreceptor

First-order somatic sensory neurons are_____neurons whose cell bodies are located in the_____.

a. Multipolar, posterior horn

b. Pseudounipolar, posterior root ganglion

c. Bipolar, anterior horn

d. Pseudounipolar, posterior horn

______detect the degree to which a muscle is stretched, whereas______detect the force of a muscle contraction.

What are the four types of papillae on the human tongue?