sensory receptors

Question 1

different kinds of sensory receptors neurons

Answer 1

1. DRG = pseudo-unipolar
2. sensory neurons in retina = rods and cones
3. olfactory bulb
4. auditory nerve

Question 2

classification of receptors on basis of energy form

Answer 2

1. mechanoreceptors
2. photoreceptors
3. thermoreceptors
4. chemoreceptors

Question 3

energy form

Answer 3

on the basis of the energy that each receptor will respond to

Question 4

adequate stimulus

Answer 4

a type of energy form that is appropriate for that receptor

Question 5

mechanoreceptors

Answer 5

respond to mechanical stimulation such as pressure

Question 6

photo receptor

Answer 6

light energy

Question 7

chemo receptor

Answer 7

chemical energy such as osmotic pressure

Question 8

thermo receptor

Answer 8

thermal energy

Question 9

classification of receptors on basis of function

Answer 9

1. exteroceptors
2. interoceptors

Question 10

types of exteroceptors

Answer 10

1. distance receptors
2. contact receptors

Question 11

exteroceptors

Answer 11

stimuli coming from outside of the body
- divided into 2 classes

Question 12

distance exteroceptor receive

Answer 12

light, sound, etc

Question 13

contact exteroceptor receive

Answer 13

touch, pressure, pain

Question 14

types of interceptors

Answer 14

1. equilibrium receptors
2. proprioceptors (position and movement of muscles and joints)
3. visceroceptors

Question 15

equilibrium receptors

Answer 15

position in space, in the inner ear

Question 16

proprioceptors

Answer 16

unconscious sensation of the body

Question 17

visceroceptors

Answer 17

chem, glucose, pH, oxygen receptors

Question 18

structural classification of sensory receptors

Answer 18

1. free nerve ending
2. nerve ending associated with accessory structure
3. nerve ending associated with specialized receptor cells

Question 19

free nerve ending

Answer 19

simplest!
- neurons with terminals that have no capsules and no specialized apparatus in their endings
- ex: pain receptors

Question 20

nerve ending associated with accessory structures

Answer 20

e.g. pacinian corpuscle - mechanical touch
- myelinated nerve with the connective tissue wrapped around its nerve ending

Question 21

nerve ending associated with specialized receptor cells

Answer 21

e.g. taste receptor
- specialized receptor cells that the nerve ending synapses
- bipolar afferent neurons synapse with taste receptors that pick up taste

Question 22

physiological classification of receptors

Answer 22

• based on adaptation
  1. slowly adapting
  2. rapidly adapting
  3. very rapidly adapting

Question 23

receptive field

Answer 23

area in the periphery where application of an adequate stimulus will cause the receptor to respond

Question 24

example receptive field

Answer 24

• DRG (somatosensory pain afferent)
• the central process goes into the spinal cord
• peripheral process innervates an area of the skin
• area innervated by this neuron has a receptor field in the periphery

Question 25

sensory transduction

Answer 25

you apply a stimulus, the NS doesn't understand bc energy forms have to be converted into APs - converts a stimulus from that energy form into action potentials (spikes) that carry the information of the stimulus ex: DRG

Question 26

generator potentials

Answer 26

- intracellular recordings from the afferent nerve fiber - in corpuscles - insert probe - apply a force - stimulus is recorded into afferent fiber - electrical depolarizations captures

Question 27

receptor potentials (taste receptor)

Answer 27

- recorded in receptor cells - taste substance contacts the taste receptor cells - change in voltage - release synaptic vesicles - activate the afferent neuron - AP

Question 28

electrotonic (local) potentials properties

Answer 28

- passive - decrement in space - graded - can summate - can initiate action potential (like IPSP and EPSP)

Question 29

electrotonic (local) potentials types

Answer 29

- receptor potentials (in receptor cells) - generator potentials (in neuron) - synaptic potentials - sub-threshold potentials

Question 30

transduction process

Answer 30

1. stimulus 2. local change in permeability 3. local depolarization (generator potential) 4. conducted action potential

Question 31

muscle spindles and their coding

Answer 31

- specialized muscle cells - afferent sensory neurons wrap around these cells - spindle is stretched so afferent neuron fires - the more you stretch the more firing you get

Question 32

muscle spindles

Answer 32

- cells in muscles - receptor for muscle stretch - striated endings - proprioceptors - inside the intrafusal muscle fibers (rest of muscle fibers are extrafusal)

Question 33

frequency coding

Answer 33

- if you suspend a weight on muscle then stretch it... *the more weight = more stretch = more spikes/minute* - they tell us how the intensity of the stimulus is coded

Question 33

muscle spindle recording`

Answer 33

record from spindle down the axon toward the body

Question 34

frequency coding relationship when graphed

Answer 34

logarithmic

Question 35

Weber-Fechner Law

Answer 35

- harder to discriminate stimulus intensity when sound is loud - easier to discriminate when sound is lower

Question 36

how is stimulus intesity coded?

Answer 36

1. frequency of impulses 2. recruitment of more afferents

Question 37

sensory adaptiation

Answer 37

sensation produced by a constant stimulus declines with time

Question 38

adaptation when graphed

Answer 38

stimulus applied for extended period of time: - initially: high frequency ~adaptation~ - reduction of frequency and can even reach zero

Question 39

do all receptors have adaptation? do they all adapt the same?

Answer 39

- no, pain receptors do not - no, have different speeds

Question 40

very rapidly adapting receptors

Answer 40

ex: Pacinian Corpuscle for vibration - respond to changes in stimulation (burst of excitation)

Question 41

Pacinian Corpuscle Adaptation

Answer 41

- apply a pressure stimulus to the Pacinian Corpuscle - it gives you a spike on the onset of the stimulus, just one spike. - A vibrating stimulus is needed for a decent response, a train of impulses is generated, - then the brain will know that the Pacinian Corpuscle is being stimulated.

Question 42

slowly-adapting receptors

Answer 42

respond only to the presence or absence of stimulus