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Flashcards in Sensory Receptors Deck (15):
1

In cutaneous sensory receptors, the nerve endings

are protected by a capsule

2

In many cases, the stimulus required to trigger an AP depends on

causing a membrane deformation which activates stretch sensitive ion channels

3

Stretch sensitive ion channels may be present

in the distal tip of the affront axon or in specialised sensory cells that then release neurotransmitter to create a generator potential in the axon's dendrites

4

Explain sensory transduction in the skin

The transduction process in all sensory endings involves opening or closing of ion channels

5

Explain frequency coding

- the bigger the stimulus, the greater the receptor potential and therefore the higher the frequency of APs
- this is the frequency coding of APs
- high frequency = high stimulus intensity

6

What do muscle spindles monitor?
What is this important for?

Muscle length and the rate at which it changes

Important for reflexes as well as voluntary movement

7

What fibres is skeletal muscle made up of?

Extrafusal and intrafusal fibres

8

Extrafusal fibres are

regular muscle fibres

9

Intrafusal fibres have

specialised motor and sensory innervation from muscle spindles

10

The end of intrafusal fibres contains

sarcomeres and are contractile

11

Intrafusal fibres are controlled by

gamma motoneurones

12

Muscle stretch is the

adequate stimulus for these receptors

13

As the muscle lengthens,

ion channels open and so length is monitored

14

Describe the efferent control of spindle function

- agonist muscle contracts, spindle contracts and output is decreased
- this causes antagonistic muscle to lengthen and those spindles increase their outflow of APs
- this allows you to know exactly what is happening around the joint position

15

Describe the role and mechanism of action of the Golgi tendon organs

- monitor muscle tension
- nerve endings are intermingled with the tendons at the ends of muscles
- act as stretch receptors and monitor the stretch in tendons
- since tendons are inelastic, the muscles must develop tension to stretch them and so measure muscle tension