Somatosensory III

Question 1

what are noiciceptors?
what kind of receptor
what do they respond to and measure

Answer 1

nociceptors detect tissue damage, and aid in the response

they are chemoreceptors

respond to damage and measure inflammation

Question 2

thermally gated receptors

Answer 2

heat deforms the channel, which allows ions to flow in or out

Question 2

you stretch type 1a, 2 and 1B fibres. how do they respond

you contract type 1a, 2 and 1B fibres. how do they repsond

if one contracts muscle hard. what is the outcome on EMG and GTO firing rate?

Answer 2

1a and 2, when stretched are very sensitive to it, and fire many action potentials
1B, not very sensitive to stretch, not many action potentials

1a and 2, when contracted are not very sensitive to it, and don’t fire many action potentials
is 1a or 2 are not slack like they are here, they fire normal amounts
1B, very sensitive to stretch, many action potentials fired

if one contracts very hard, high EMG output, and high amounts of GTO output

Question 2

when do thermoreceptors not sense a difference between temps and what happens to their action potential firing rate

what happens to nociceptors and their action potential rate at higher temps

Answer 2

thermoreceptors reach a cap at around 43 degrees celsius
so they can’t tell the dif between 50 or 100
their action potential firing rate stays the same

what do begin to fire around then is nociceptor
so their action potentials increase

so the extra sensation difference from above 50 doesn’t come from thermoreceptors, but from the extra tissue damage, and then the nociceptor measuring that.

Question 3

Golgi Tendon organ makeup
1. where are they?
2. how do they work?
3. what do they measure?
4. how many fibres per on GTO?
5. what TYPE OF AFFERENT?
6. what are they more sensitive too?
7. and not sensitive too?

Answer 3

attach between muscles and tendons. are made of collagen strands, and have TYPE 1B afferents through them

when muscles contract the collagen crushes the afferents and the mechanically gated channels on it allowing for Na+ to rush in and for an action potential to occur

3. provide feedback on muscle force production
4. 10-20 muscle fibres to one GTO
5. type 1B afferent
6. they are sensitive to ACTIVE FORCE PRODUCTION by muscle fibres.
7. sensitive to small amounts of contraction, but need big amounts of stretch to fire action potentials

Question 4

why is capsaicin spicy?
how does its form let it do what it does?

Answer 4

capsaicin is lipid-based and can go right thru the membrane and attach to a thermoreceptor

this receptor measures heat, and capsaicin opens it, allowing ions to flow in

makes the receptor think its being fired but its being fired without heat

artificial heat

Question 5

what do joint receptors do?
can they know the difference between things?

1/2 fire at what
1/4 fire at what

Answer 5

joint receptors measure twist, flexion, extension, and pressure in the joint but can’t know the difference between them they just tell us something is happening in the joint.

1/4 fire at extreme angles in ONE DIRECTION

1/2 fire at extreme ends of both ends of ROM

Question 6

three types of receptors for PROPRIOCEPTION

what things help in touch

pain and temperature

which conduct the fastest, fastest to slowest

Answer 6

PROPRIOCEPTION: type 1a(primary), 2(seconday), and 1b(GTO)—— fast conduction velocity

TOUCH: cutaneous and joints, PMMR, and Joints. slower conduction than proprioception

PAIN AND TEMP: nerve endings, thermoreceptors, and noiciceptors. slowest conduction

MTP
muscle, touch, pain
Muscle spindles and GTO have the fastest conduction velocity
Touch have the second
and pain and temp are last