L10: Simple Reflexes

Question 1

What is a reflex

Answer 1

Stereotypes involuntary reaction of the CNS to specific sensory input

Question 2

Which nervous system does a reflex involve

Answer 2

Somatic

Autonomic

Question 3

What is the the effector of the somatic NS

Answer 3

Skeletal muscle

Question 4

What is the effector of the autonomic ns

Answer 4

Smooth muscle
Cardiac muscle
Secretory glands

Question 5

What are the 3 general function of reflexes

Answer 5

Protection
Postural control
Homeostatis

Question 6

What are the 5 elements involved in a reflex arc

Answer 6

Sensory receptor
Afferent neurone 
Integration at CNS via interneurones 
Efferent 
Effector

Question 7

Where are the 2 places that interneurones exist at

Answer 7

Within CNS

Within ENS

Question 8

What is a simple stretch reflex/myotatic reflex for

Answer 8

Posture

Question 9

What are the sensory receptors in a simple stretch reflex

Answer 9

Propioceptors

Question 10

What are the examples of a simple stretch reflex

Answer 10

Muscle spindle

Golgi tendon organ

Question 11

Describe the process involved in a muscle spindle

Answer 11

1) stretch/movement is detected by propioceptors and converted into AP
3) an excitatory neurotransmitter is released from sensory afferent to alpha motor neurone
4) muscle contracts to prevent muscle damage

Question 12

Which other reflex uses muscle spindles

Answer 12

Knee jerk reflex

Question 13

What does the knee jerk reflex involve

Answer 13

Inhibitory interneurones so one muscle contracts and the other relaxes

Question 14

Describe the simple stretch reflex in golgi tendon organs

Answer 14

1) contraction of the skeletal muscle pulls the tendon and squashes the nerve endings
2) AP is generated in the sensory neurone to the integration centre
3) sensory neurones release excitatory neurotransmitter to the interneurones
4) interneurones release inhibitory neurotranmitters to the efferent neurone
5) muscle then relaxes

Question 15

When can this reverse myotatic reflex become activated

Answer 15

During heavy lifting

Question 16

What is a withdrawal reflex

Answer 16

A reflex that does not use propioceptors

Question 17

What is an example of a withdrawal reflex

Answer 17

Crossed extensor reflex

Question 18

Describe what occurs in a crossed extensor reflex

Answer 18

1) sensory receptors detect pain and generate AP
2) interneurones release both excitatory and inhibitory neurotransmitter to the efferent neurones
3) muscle relaxes and contracts