Lecture 66 sensory and motor pathways in the spinal cord

Question 1

Sensory information enters what part of the spinal cord?

Answer 1

dorsal

Question 2

Motor information (response) exits what part of the spinal cord?

Answer 2

ventral

Question 3

Sensory information from the head and neck enter the CNS via

Answer 3

cranial nerves

Question 4

Sensory information from the body enters the CNS via

Answer 4

the dorsal/posterior branch of each pair of spinal nerves

Question 5

Sensory neurons are what kind of neurons?

Answer 5

uni and pseudounipolar - their cell bodies are in the dorsal root ganglion entering the spinal cord

Question 6

Which pathway (ascending or descending) do sensory neurons act in?

Answer 6

ascending

Question 7

Sensory receptors are modality specific, meaning

Answer 7

they respond only to one type of stimulus (like temperature or touch, but rarely both)

Question 8

Better localization in pressure and touch is known as

Answer 8

acuity or discrimination

Question 9

What is lateral inhibition?

Answer 9

a process that creates better spacial localization; a stimulated neuron can inhibit surrounding weakly inhibited neurons - this allows for a person to know exactly where an injury is by the point of pain because it creates a contrast

Question 10

T or F: temperature and pain receptors are well localized

Answer 10

false (think of referred pain)

Question 11

Which type of adaptation (rapid or slow) is often used to signify the start or end of a stimulus?

Answer 11

rapid; slow signals prolonged stimulation

Question 12

Do rapidly adapting receptors cease firing after the stimulus is initially applied, even if the stimulus is still there?

Answer 12

yes, they will often fire briefly again when the stimulus stops

Question 13

Free nerve endings are abundant in what kinds of tissue?

Answer 13

epithelia and underlying connective

Question 14

Free nerve endings respond to

Answer 14

pain and temperature as well as light pressure and hair movement

Question 15

Which kinds of receptors tend not to adapt?

Answer 15

Free or unencapsulated

Question 16

Encapsulated nerve endings are mostly

Answer 16

corpuscles

Question 17

All encapsulated nerve endings are enclosed in

Answer 17

connective tissue capsules

Question 18

What is the function of encapsulated nerve endings?

Answer 18

amplification of stimulus/specificity

Question 19

Proprioreceptors monitor

Answer 19

stretch; therefore maintain balance and posture

Question 20

What are the three subtypes of proprioreceptors?

Answer 20

muscle spindles, golgi tendon organs and joint kinesthetic receptors

Question 21

Muscle fibers have what main function?

Answer 21

stretch monitoring and balance maintenance

Question 22

Referred pain is due to poor discrimination and

Answer 22

convergence

Question 23

The pyramidal tracts are also known as the

Answer 23

corticospinal tracts

Question 24

The pyramidal tracts control what type of movement

Answer 24

precise/skilled

Question 25

The pyramidal tracts exit near the

Answer 25

basal ganglia

Question 26

The extrapyramidal tracts include what five tracts?

Answer 26

tectospinal, vestibulospinal, rubrospinal, lateral and medial reticulospinal

Question 27

The tectospinal tract is involved in

Answer 27

moving the head to respond to sound

Question 28

Which extrapyramidal tract is involved in muscle tone and balance?

Answer 28

the vestibulospinal tract (rubrospinal also does muscle tone)

Question 29

What tracts are involved with unskilled movements?

Answer 29

the lateral and medial reticulospinal