Sensory Receptors

Question 1

Which of the following receptors is responsible for sensation of joint rotation?

Answer 1

Ruffini’s end organ

Question 2

Sensory receptors

Answer 2

afferent receptors that take info to the CNS. The types are: free nerve ending (touch and pressure), Pacinian corpuscles (fast vibration, 30-800 Hz), Ruffini’s end organ (pressure and joint rotation), Meissner’s corpuscle (touch, slow vibration, 2-80Hz), and Golgi tendon apparatus (muscle stretch and load)

Question 3

Labeled line

Answer 3

referring to each stimulus going to specific line of the brain

Question 4

How does the body know when a sensory receptor is receiving more or less stimulation (eg. kinda painful vs super painful)?

Answer 4

By more or less frequent action potentials. When a receptor is stimulated, it approaches its receptor potential threshold, this causes firing of action potentials, the higher the stim rises above the threshold, the greater the frequency of action potential.

Question 5

How do receptors adapt?

Answer 5

with prolonged stimulation, the frequency of action potentials falls, Pacinian receptors (phasic receptor) adapt rapidly, while joint capsules golgi tendon adapt slowly (tonic receptor).

Question 6

How can intensity be increased?

Answer 6

spatial summation which is progressively greater numbers of fibers firing simultaneously. Temporal summation which is fixed numbers of fibers firing with increased frequency.

Question 7

How is fast vs chronic pain transported?

Answer 7

Fast, sharp pain from mechanical or heat travels on small A-delta fibers between 6-30m/sec
Slow, chronic pain from chemical, mechanical, or thermal stimuli travels on c fibers between 0.5 and 2m/sec

Question 8

Which nerve fiber is most specific for localized nocioception?

Answer 8

A delta fibers which are glutamate carriers that terminate in the dorsal horn. The sign excited second order neurons that decusate and travel to the thalamus, terminating in the ventrobasal complex.

Question 9

Slow C-type fibers

Answer 9

terminate in substantia gelatinosa of the dorsal horns, and stimulate intralaminar nuclei of thalamus. Does not really localize in paleospinothalamic tract which is autonomic and emotional part of pain.

Question 10

True or false: substance P is slow

Answer 10

true

Question 11

What keeps people awake when in pain?

Answer 11

stimulation of intralaminar nuclei

Question 12

Muscle spindles

Answer 12

in belly of the muscle, give info about muscle length and rate of change; no actin or myosin, contract end portion via gamma motor nerve, mid portion is sensory

Question 13

Golgi tendon organs

Answer 13

located in the muscle tendon, give info about tendon tension and rate of change of tension

Question 14

What are the two types of sensory fiber endings?

Answer 14

Primary (annulospiral) - activated in both slow and rapid lengthening of muscle spindle; static stretch reflex or dynamic
Secondary ending (bush branches) - activated only during slow lengthening; dynamic

Question 15

How are jerk flexes mediated?

Answer 15

Afferent signal from muscle spindle fiber via Type Ia proprioceptor nerves which enter the dorsal root resulting in a monosynaptic efferent motor signal.

Question 16

What’s alpha gamma loop?

Answer 16

A feedback loop in our nervous system that regulates the level of tension in our muscles by activating gamma neurons, spindle fibers, stretch receptors, and increases firing of alpha motor neurons.

Question 17

Golgi tendon reflex

Answer 17

When stress on a tendon becomes too great the Golgi tendon organs send afferent signals that excite inhibitory interneurons. This: 1. prevents excess stress on muscles and tendons, protecting against injury. 2. Allows stress to be evenly distributed across an entire muscle rather than