Sensory Receptors SDL

Question 1

What are the five types of sensory modalities?

Answer 1

Vibration, Mechanical, EM, Thermal, Chemical

Question 2

The Three sensory receptor types?

Answer 2

Exteroceptors, Interoceptors, Proprioceptors

Question 3

What are the Somatosensory receptors?

Answer 3

mechanoreceptors, nocioceptors, thermoreceptors

Question 4

3 for discrete tactile stimuli?

Answer 4

Meissner, Hair follicle receptor, merkel disc

Question 5

For thermoreceptor and sometimes norciceptors?

Answer 5

free nerve ending

Question 6

What do Pacinian corpuscles detect?

Answer 6

vibration

Question 7

what doe Ruffini endings detect?

Answer 7

stretching of the skin

Question 8

Generator Potential

Answer 8

graded: amount depends on stimulus

non-propagating: does not propagate along sensory neuron

Question 9

What happens with potential in Pacinian Corpuscle?

Answer 9

1. channels open leading to generator potential
2. leads to axon potential
   (mechanical to electric signal)

Question 10

How does the receptor tell between a light or painful touch?

Answer 10

as stimulus intensity increases, sensory receptor’s firing freq increases, more receptors fire

Question 11

Theory of Sensation

Answer 11

the pattern created by the action potentials of sensory fibers tells nature of stimulus

Question 12

Phasic Receptor?

Answer 12

completely adapts to stimulus, quits firing

Question 13

Tonic Receptor?

Answer 13

continue to fire as long as stimulus is there

Question 14

Habituation

Answer 14

@ CNS level

brain pays less attention to stimulus

Question 15

Adaption

Answer 15

@ receptor level

receptor decreases its firing

Question 16

Receptor Field

Answer 16

area of skin that is innervated by on soma

Question 17

Lesion and two point discrimination

Answer 17

If there is a lesion, 2 pt discrimination will be bad

Question 18

What makes conduction quick?

Answer 18

thicker and myelinated

Question 19

A-Beta fibers

Answer 19

touch and pressure

fastest

Question 20

A-Gamma fibers

Answer 20

pain, temp, touch

2nd fastest

Question 21

C fibers

Answer 21

pain, reflex responses

slowest

Question 22

Sharp, Pricking pain

Answer 22

fast and first

A-gamma, easy to localize

Question 23

Burning, dull pain

Answer 23

slow, second pain

C fibers, not easy to localize

Question 24

How does Lidocaine work?

Answer 24

blocks Na+ channels on C fibers, will feel sharp pain but not dull pain

Question 25

What does substance P and PGs do?

Answer 25

increase sensitivity of nerve endings –> painful area during healing

Question 26

What is released when tissue damage occurs?

Answer 26

bradykinin, serotonin, histamine, K+, ACh, proteolytic enzymes

Question 27

Triple vascular response

Answer 27

redness- local vasodilation
flare - vasodilation in wider area by axon reflex
weal - edema

Question 28

Golgi Tendon

Answer 28

1. arranged in series
2. detects tension
3. send info out by Ib fiber (a-alpha)

Question 29

Muscle spindle

Answer 29

1. parallel with muscle fibers
2. detects stretch of muscle
3. sends info by Ia and II nerve fiber
4. reports change of muscle length and rate of change e

Question 30

What are extrafusal fibers activated by?

Answer 30

alpha-motor neurons

Question 31

what are intrafusal fibers activated by?

Answer 31

gamma- motor neurons

Question 32

Process of contraction

Answer 32

1. stim of alpha MN –> muscle contraction
2. shortening of muscle
3. golgi tendon detects tension
4. see signal from this
   * do not see signal from muscle spindle

Question 33

Process of Stretch

Answer 33

1. muscle spindle stretched and intrafusal

* intrafusal fiber and golgi tendon also registers stretch

Question 34

How does muscle spindle not become floppy during contraction?

Answer 34

gamma motor neuron activates the intrafusal muscles fibers and causes contraction
*still sensitive to length of muscle mass