Sensory Receptors 2

Question 1

What is a proprioreceptor?

Answer 1

A proprioreceptor is a mechanoreceptor that signals the bodies or limbs position

Question 2

What are examples of proprioreceptors?

Answer 2

Examples of proprioreceptors are:

Muscle spindle

Golgi tendon organs

Joint receptors

Question 3

What does the muscle spindle do?

Answer 3

The muscle spindle monitors the muscle length and rate of change of muscle length

Controls reflexes and voluntary movement

Question 4

What does the golgi tendon organ do?

Answer 4

The golgi tendon organ monitors the tension on a tendon

Question 5

What does a joint receptor do?

Answer 5

A joint receptor monitors the joint angle, rate of angular movement and the tension on the joint

Question 6

What are the three things that proprioreceptors do?

Answer 6

Allow the brain to control voluntary movement by sending sensory information

Muscle spindle and golgi tendon organs give sensory information that drives spinal cord reflex

Percieve limb and body position and movement in space (kinaesthesia)

Question 7

What is the muscle spindle composed of?

Answer 7

The muscle spindle is composed of intrafusal and intrafusal muscle fibres

Question 8

What are the intrafusal muscle fibres contained in?

Answer 8

Intrafusal muscle fibres are contained in a capsule and have their own sensory and motor innervations

Lie parralel to muscle fibre

Question 9

How do intrafusal muscles lie in relation to the muscle fibres?

Answer 9

Lies parralel

Question 10

What does the alpha motor neuron do?

Answer 10

The alpha motor neuron goes to the extrafusal muscle fibre and makes it contract

Question 11

What does the gamma motor neuron do?

Answer 11

The gamma motor neuron goes to the intrafusal muscle fibre at each end

Question 12

What are the two types of intrafusal fibres?

Answer 12

The two types of intrafusal fibres are:

Nuclear bag fibre

Nuclear chain fibre

Question 13

What are nuclear bag fibres?

Answer 13

Nuclear bag fibres are bag shaped with nuclei collected together

Question 14

What are nuclear chain fibres?

Answer 14

Nuclear chain fibres are nuclei lined up in a chain

Question 15

Are muscle fibres multi or mono nucleic?

Answer 15

Muscle fibres are multinucleic

Question 16

What does a diagram showing the contractile and non contractile end of a muscle fibre look like?

Question 17

What are the two ends of a intrafusal muscle fibre innervated by?

Answer 17

Gamma fibres

Question 18

What part of the intrafusal muscle fibre contracts?

Answer 18

The ends, not the middle

Question 19

What are annulospiral endings?

Answer 19

Primary endings from type I alpha afferent nerves wrap around centre of the intrafusal fibre

Question 20

What are flower spray endings?

Answer 20

Secondary endings from type II afferent

Question 21

What happens when the gamma fibre fires?

Answer 21

Ends contract and shorten

Middle stretches

Question 22

What stimulates the spindle stretch receptors?

Answer 22

The muscle stretching

Question 23

What happens when a stretch stimulates the spindle stretch receptors?

Answer 23

1. Stretch sensitive ion channels open
2. Causes generator potential
3. Causes action potential

Question 24

What does the resting action potential depend on during a stretch?

Answer 24

The length L_o

Question 25

What does the action potential frequency depend on during a stretch?

Answer 25

The velocity of the stretch from L₀ to L₁

Question 26

What happens to the action potential frequency after the stretch?

Answer 26

After a stretch the action potential frequency is at a new steady state (L₁ > L₀)

Question 27

What is joint movement organised by?

Answer 27

Joint movement is organised by groups of muscles working opposite to each other

Question 28

What is a relationship around a joint between the agonist and the antagonist?

Answer 28

When the agonist contracts the antagonist relaxes

Question 29

What does contracting a muscle mean?

Answer 29

Shortening the muscle

Question 30

What does the golgi tendon organ do (GTO)?

Answer 30

The golgi tendon organ monitors muscle tension

Question 31

What is the relationship between the golgi tendon organ and the tendon?

Answer 31

Nerves endings of the golgi tendon organ mingle with tendon bundle at the end of the muscle, so they monitor the stretch of the tendon

Question 32

How do passive stretches affact the tendon?

Answer 32

Passive stretches do not effect the tendon much unlike muscle spindle because they are inelastic

Question 33

How do muscles develop tension?

Answer 33

By contracting to stretch the tendon

Question 34

What happens to the tension in a tendon when a muscle fibre contracts?

Answer 34

It increases the tension

Question 35

How does the muscle spindle and the golgi tendon organ lie in relation to the extrafusal muscle fibre?

Answer 35

Muscle spindle lies parralel and the golgi tendon organ lies in series

Question 36

What is the function of the gamma motor neuron?

Answer 36

Contract the poles of the muscle spindle so it matches the muscle

Question 37

Where do the alpha and gamma neurons connect to?

Answer 37

Alpha goes to the muscle

Gamma goes to the muscle spindle

Question 38

What happens to the gamma motor neuron when the alpha is activated?

Answer 38

Alpha is activated to cause contraction

Gamma is activated in parralel to maintain spindle selectivity (tension matches new muscle length)

Question 39

What is an example of proprioreceptors acting autonomically?

Answer 39

Controlling movement such as the spinal cord reflex