Chapter 7

Question 1

Explain what it means to say that sensory systems are organized by hierarchical organization?

Answer 1

Sensory systems are thought to be hierarchical in two ways

1. Sensory info is thought to flow through brain structures in order of their increasing neuroanatomical complexity
2. Sensation is thought to be less complex than perception

Question 2

What are the 3 separate systems composing the somatosensory system?

Answer 2

1. Exteroceptive cutaneous system
2. Proprioception System (monitors body position)
3. Interoceptive system (monitors conditions within the body such as blood pressure)

Question 3

Free nerve endings are sensitive to _______ and ________

Answer 3

Changes in skin temperature

Pain

Question 4

List the 2 primary pathways for which somatosensory information ascends from the skin to the cortex

Answer 4

Dorsal column medial-lemniscus system carries info about touch and proprioception to the cortex.

The anterolateral system carries some crude info about touch, but it’s primary function is to mediate the perception of pain and temperature

Question 5

Describe the differences between primary sensory cortex, secondary sensory cortex, and association cortex

Answer 5

• Primary sensory cortex is the cortex that receives input directly from thalamic sensory relay nuclei
• The secondary sensory cortex of a sensory system receives input primarily from the primary sensory cortex of that system
• Association cortex is cortex that receives input from more than one sensory system

Question 6

_______ are cutaneous receptors that adapt rapidly and do not respond to constant pressure

Answer 6

Pacinian corpuscles

Question 7

_______ are cutaneous receptors that adapt slowly and respond to gradual skin indentation

Answer 7

Merkels disks

Question 8

______ are cutaneous receptors that adapt slowly and respond to skin stretch

Answer 8

Ruffini endings

Question 9

What is a dermatome?

Answer 9

Area of the body that is innervated by the left and right dorsal roots of a given segment of the spinal cord

Question 10

List and define the 2 primary types of somatosensory agnosias

Answer 10

• Astereognosia is the loss of the ability to recognize objects by touch in the absence of defects in somatosensation
• Asomatognosia is a loss of the ability to recognize parts of ones own body

Question 11

What is the cortical area most frequently associated with pain?

Answer 11

Anterior cingulate cortex

Question 12

Electrical stimulation of the __________ has analgesic effects

Answer 12

Periaqueductal Gray Area

Question 13

List 2 characteristics of selective attention

Answer 13

1. Impores the perception of stimuli that are in focus

2. Interferes with the perception of stimuli that are in focus