7.2 The Mechanical Senses

Question 0

The ____ ____ respond to pressure, bending, or other distortions of the receptor. They include touch, pain, and other body sensations, as well as vestibular sensation, which detects the position and movement of the head.

Answer 0

mechanical senses

Question 1

Vestibular sensation. When you move your head, the ____ ____ adjacent to the cochlea monitors movement and directs compensatory movements of your eyes.

Answer 1

vestibula organ

Question 2

Sensations from the vestibular organ detect the direction of tilt and the amount of acceleration of the head. Vestibular sensations are critical for guiding eye-movement and ____ ____.

Answer 2

maintaining balance

Question 3

The vestibular organ, consists of the ____, ____, and three semicircular canals.

Answer 3

saccule : utricle

Question 4

The vestibular receptors are modified ____ receptors.

Answer 4

touch

Question 5

Calcium carbonate particles called ____ lie next to hair cells, when the head tilts in different directions, the otoliths push against different sets of hair cells and excite them.

Answer 5

otoliths

Question 6

The three ____ ____, oriented in perpendicular planes, are filled with a jellylike substance and lined with hair cells.

Answer 6

semicircular canals

Question 7

Acceleration of the head at any angle causes the ____ ____ in one of these canals to push against the hair cells.

Answer 7

jellylike substance

Question 8

Action potentials initiated by cells of the vestibular system travel through part of the ____ ____ ____ to the brainstem and cerebellum. (The eighth cranial nerve contains both an auditory component and a vestibular component.)

Answer 8

eighth cranial nerve

Question 9

The ____ system, the sensation of the body and its movements, is not one sense but many, including discriminative touch (which identifies the shape of an object), deep pressure, cold, warmth, pain, itch, tickle, and the position and movement of the joints.

Answer 9

somatosensory

Question 10

Receptor: ____ ____ ____. Location: near base of hairs and elsewhere in skin. Responds to: pain, warmth, cold.

Answer 10

Free nerve ending

Question 11

Receptor: ____ ____. Location: hair-covered skin. Responds to: movement of hairs.

Answer 11

Hair-follicle receptors

Question 12

Receptor: ____ ____. Location: hairless areas. Responds to: sudden displacement of skin; low-frequency vibration (butter).

Answer 12

Meissners corpuscles

Question 13

Receptor: ____ ____. Location: both hairy and hairless skin. Responds to: sudden displacement of skin; high-frequency vibration.

Answer 13

Pacinian corpuscles

Question 14

Receptor: ____ ____. Location: both hairy and hairless skin. Responds to: light touch.

Answer 14

Merkel’s disks

Question 15

Receptor: ____ ____. Location: both hairy and hairless skin. Responds to: stretch of skin.

Answer 15

Ruffini endings

Question 16

Receptor: ____ ____ ____. Location: mostly or entirely in hairless areas, perhaps including genitals. Responds to: uncertain.

Answer 16

Krause end bulbs

Question 17

A ____ ____ maybe a simple bare neutron ending (e.g., many pain receptors), a modified dendrite (Merkel’s discs), an elaborated neuron ending (Ruffini endings and Meissner’s corpuscles), or a bare ending surrounded by other cells that modify its function (Pacinian corpuscles).

Answer 17

touch receptor

Question 18

Stimulation of a touch receptor opens ____ channels in the axon, thereby starting an action potential.

Answer 18

sodium

Question 19

Information from touch receptors in the head enters the central nervous system (CNS) through the ____ ____.

Answer 19

cranial nerves

Question 20

Information from receptors below the head enters the spinal-cord and passes toward the brain through the 31 ____ ____, including 8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves, 5 sacral nerves, and 1 coccygeal nerve.

Answer 20

spinal nerves

Question 21

Each spinal nerve has a ____ component and a ____ component.

Answer 21

sensory : motor

Question 22

Each spinal nerve innervates (connects to) a limited area of the body called a ____. Each dermatome overlaps one third to one half of the next dermatome.

Answer 22

dermatome

Question 23

The various areas of the somatosensory thalamus send their impulses to different areas of the ____ ____ ____, located in the parietal lobe.

Answer 23

primary somatosensory cortex

Question 24

To parallel strips in the ____ ____ respond mostly to touch on the skin. Two other parallel strips respond mostly to deep pressure and movement of the joints and muscles.

Answer 24

somatosensory cortex

Question 25

The primary somatosensory cortex is essential for touch experiences. Damage to somatosensory cortex impairs ____ ____.

Answer 25

body perceptions

Question 26

____, the experience provoked by harmful stimulus, directs your attention toward a danger and holds your attention.

Answer 26

Pain

Question 27

With pain the ____ cortex continues responding as long as the pain lasts.

Answer 27

prefrontal

Question 28

Pain sensation begins with the least specialised all receptors, a ____ ____ ____.

Answer 28

bare nerve ending

Question 29

____, the chemical found in hot peppers such as jalapenos, also stimulates the receptors for painful heat. ____ can produce burning or stinging sensations on many parts of your body.

Answer 29

Capsaicin

Question 30

The axons carry pain information have little or __ ____ and therefore conduct impulses relatively slowly, and the range of 2 to 20 m/s.

Answer 30

no myelin