Somatosensation

Question 1

dorsal roots

Answer 1

carries sensory info into the spinal cord from the body

Question 2

ventral roots

Answer 2

carry motor commands out of the spinal cord to the muscles

Question 3

dermatome

Answer 3

the area of skin innervated by a single spinal nerve

Question 4

transducers

Answer 4

somatosensory nerve endings in the skin

Question 5

transduction

Answer 5

the conversion of energy from one form into another

Question 6

discriminative touch

Answer 6

pressure, vibration, texture
sensed by mechanoreceptors in the skin
travels to the brain via the dorsal column spinal pathway

Question 7

proprioception

Answer 7

position of joins and limbs
sensed by mechanoreceptors in muscles and tendons
travels to the brain via the dorsal column spinal pathway

Question 8

pain and temperature

Answer 8

tissue damage, heat, cold
sensed by chemoreceptors in the skin
travels to the brain via the spinothalamic tract

Question 9

gray matter

Answer 9

neurons and dendrites

Question 10

dorsal horn

Answer 10

sensory interneurons in gray matter

Question 11

ventral horn

Answer 11

motor neurons in gray matter

Question 12

white matter

Answer 12

myelinated axons that form tracts

Question 13

ascending tract

Answer 13

carry signals form the spinal cord to the brain

Question 14

descending tract

Answer 14

carry signals from the brain to the spinal cord

Question 15

dorsal column pathway

Answer 15

DRG axons enter spinal cord and bifurcate into two branches

Question 16

anterolateral pathway

Answer 16

DRG axons enter the spinal cord and synapse onto interneurons in the superficial layers of the dorsal horn

Question 17

spike trains

Answer 17

sequences of APs that each dorsal root ganglion neuron fires

Question 18

firing rate

Answer 18

the number of spikes that a neuron fires per unit time

Question 19

fast adapting discriminative touch mechanoreceptors

Answer 19

Pacinian corpuscle - pressure and vibration

Meissner’s corpuscle - light touch

Question 20

slow adapting discriminative touch mechanoreceptors

Answer 20

Merkel’s discs - light touch

Ruffini endings - pressure and vibration

Question 21

spinal withdrawal reflex

Answer 21

an automatic response to a painful stimulus

involves only neurons in the spinal cord because it must be rapid

Question 22

primary somatosensory cortex

Answer 22

receives much of its ascending input from the ventral posterior nucleus (VPN) of the thalamus

Question 23

homunculus

Answer 23

some body regions are more represented than others in the cortex

Question 24

proprioceptors

Answer 24

sensory organs that sense the movement and position of limbs by sensing how stretched the muscle is or how bent the joint is

Question 25

muscle spindle organs

Answer 25

detect how ‘stretched’ muscle fibers are

Question 26

golgi tendon organs

Answer 26

sense joint angle and position

Question 27

commissures

Answer 27

axon bundles that carry info from one side of the brain or spinal cord to the contralateral side from the neuron’s soma

Question 28

corpus callosum

Answer 28

major commissure that connects the left and right cerebral hemispheres in the brain

Question 29

anterior white commissure

Answer 29

where the dorsal horn interneurons that are excited by A and C fibers cross the midline in the spinal cord

Question 30

limbic system

Answer 30

a set of brain regions that regulate memory, emotions and motivated behaviors

Question 31

descending analgesia

Answer 31

inhibitory neurons in the spinal cord can ‘shut down’ pain signals before they are relayed to the brain

Question 32

cervical dermatomes

Answer 32

arms and back of head

8

Question 33

thoracic dermatomes

Answer 33

back and stomach

12

Question 34

lumbar dermatomes

Answer 34

lower back and front of legs

5

Question 35

sacral dermatomes

Answer 35

buttocks and back of legs

5

Question 36

coccygeal dermatome

Answer 36

pelvis and groin

1

Question 37

meninges

Answer 37

the membranes that surround the spinal cord