Lecture for Ch 10.1: Sensory Receptors

Question 1

What stimuli types can stimulate nocireceptors?

Answer 1

heat, cold, pressure, chemicals, pH

Question 2

What NTs are responsible for pain reception?

Answer 2

substance P and glutamate

Question 3

What can reduce pain (chemical NT class)?

Answer 3

endogenous opioids: endorphins, enkephalins, dynorphins

Question 4

If the optic nerve delivers an impulse, the brain interprets it as ______ even though the impulse is _________ for hearing

Answer 4

light; the same as

Question 5

Receptors classes: by information delivered

Answer 5

1) proprioreceptors (body position and fine muscle control)
2) cutaneous (skin, touch, texture, pressure, temperature, pain)
3) special senses (vision, hearing, taste, smell, eq)

Question 6

Receptor classes: by origin of information

Answer 6

1) exteroreceptors - respond to stim outside of body

2) interoreceptors - respond to stim inside (blood pressure, ph, [O2], etc.)

Question 7

Receptor classes: by how they respond

Answer 7

1) phasic (adapting)

2) tonic (maintained response)

Question 8

Phasic Receptor Properties

Answer 8

• respond to burst of activity when stim first applied but quickly adapt by decreasing response
• may deliver another short burst when stim removed
• alert us to changes in env.
• sensory adaptation to reduced attention to constant stim
• examples - touch, smell, temp.

Question 9

Example of tonic receptor

Answer 9

nocireceptors

Question 10

Why do we perceive a punch n the eye as a flash of light?

Answer 10

because nerve fibers can only send information about experience as their assigned sensory modality: optic nerve fibers that are stimulated can only send signals that are perceived as light

Question 11

Why does paradoxical cold exist?

Answer 11

because nerve fibers can only send information about experience as their assigned sensory modality; if cold receptors are stimulated, whether or not it is cold, they will send a signal of cold to the brain

Question 12

EPSPs in receptors are known as ….

Answer 12

generator potentials

Question 13

What is the function of the “onion skin” of pacinian corpuscles?

Answer 13

As a phasic receptor, the pacinian corpuscles have layers that help to grade/diminish the generator potential response to pressure

Question 14

How do generator potentials work in tonic receptors

Answer 14

the generator potential is proportional to the intensity of the stimulus; increase intensity results in increased freq of AP after threshold is reached

Question 15

Which cutaneous receptors are naked?

Answer 15

pain, cold, heat

Question 16

merkel’s disks

Answer 16

sense indentation; close to skin surface

Question 17

meissner’s corpuscle

Answer 17

changes in texture; close to skin surface

Question 18

pacinian corpuscle

Answer 18

deep pressure; deep in skin

Question 19

ruffini endings

Answer 19

skin stretch; deep in skin

Question 20

root hair plexus

Answer 20

light bruising; around hair follicle

Question 21

Do we have more cold receptors or more hot receptors?

Answer 21

cold

Question 22

Cold receptors are ______ by warm

Answer 22

inhibited

Question 23

What temp range do cold receptors respond to?

Answer 23

8-28 degrees C

Question 24

Cold receptors serve as an ion channel for _____ and are therefore also known as ____

Answer 24

sodium and calcium; a Transient Receptor Potential (TRP) channel

Question 25

Are warm receptors located more proximal or deep to skin than cold receptors?

Answer 25

deeper

Question 26

Warm receptors are ______ hot receptors

Answer 26

different from

Question 27

Hot receptors are also known as

Answer 27

capsaicin receptors; nocireceptors; TRP channels

Question 28

When are hot receptors activated?

Answer 28

≥ 43 degrees C or in response to chili pepper eating

Question 29

Myelinated nocireceptors produce

Answer 29

sudden sharp pain

Question 30

Unmyelinated nocireceptors produce

Answer 30

dull, persistent pain

Question 31

What causes acute itch?

Answer 31

Histamine release from mast cells and basophils

Question 32

What causes chronic itch?

Answer 32

stimulated by other chemicals and does not respond to antihistamines

Question 33

What do itch receptors stimulate?

Answer 33

unmyelinated sensory axons to the spinal cord

Question 34

the ____ receptors, the _____ the receptive field, the ________ the area in the _______ cortex

Answer 34

more; smaller; larger; somatosensory

Question 35

small receptor fields lead to _____ sensation = ______ acuity

Answer 35

sharper; tactile