Lecture 5: General Sensory Mechanisms II

Question 1

Somatic senses

Answer 1

Collect sensory information from all over the body; mechanoreceptive, thermoreceptive, pain

Question 2

Special senses

Answer 2

Refer to vision, hearing, smell, taste, equilibrium

Question 3

Exteroreceptive sensations

Answer 3

From the surface of the body

Question 4

Proprioceptive sensations

Answer 4

Refer to the physical state of the body (position, muscle sensation, pressure, equilibrium)

Question 5

Deep sensations

Answer 5

Deep pressure, pain, vibration

Question 6

What are the 3 physiological types of somatic senses?

Answer 6

Mechanoreceptive somatic senses, Thermoreceptive senses, Pain sense

Question 7

Which ascending pathways are used for conscious perception?

Answer 7

Spinothalamic system, Medial lemniscal system

Question 8

Which ascending pathways are used for unconscious perception?

Answer 8

Spinocerebellar, spino-olivary, spinotectal, spinoreticular

Question 9

What sensations does the lateral spinothalamic tract carry?

Answer 9

Pain and temperature

Question 10

What sensations does the anterior spinothalamic tract carry?

Answer 10

Light touch/crude touch, pressure, tickle itch

Question 11

What sensations does the medial lemniscus system carry?

Answer 11

Two-point sensation (fine touch), pressure, vibration

Question 12

What structure conveys sensations from below midthoracic level?

Answer 12

Nucleus gracilis

Question 13

What structure conveys sensations from above the midthoracic level?

Answer 13

Nucleus cuneatus

Question 14

Primary somatosensory area

Answer 14

Composed of Brodmann’s areas 1,2, and 3

Question 15

Somatosensory association area

Answer 15

Composed of Brodmann’s areas 5 and 7

Question 16

What are the results of widespread bilateral excision of the Somatosensory Area I?

Answer 16

Loss of fine sensation, judging degrees of pressure, judging weight/shape of objects, etc; pain and temperature preserved but poorly localized

Question 17

Somatosensory Area II

Answer 17

Receives signals from brainstem, somatosensory area I, other sensory areas; must have projections from area I for area II to function

Question 18

Layers I and II of Somatosensory cortex

Answer 18

Receive input signals from lower brain centers

Question 19

Layers II and III of Somatosensory cortex

Answer 19

Send information through corpus callosum to opposite hemisphere

Question 20

Layers V and VI of Somatosensory cortex

Answer 20

V projects to basal nuclei/brainstem/spinal cord; VI projects to thalamus

Question 21

Layer IV of Somatosensory cortex

Answer 21

Receives incoming sensory signals

Question 22

Which neurons decussate in the ascending pathways?

A. Primary sensory neurons
B. Secondary neurons
C. Tertiary neurons
D. Collateral neurons

Answer 22

B. Secondary neurons