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Flashcards in Simple reflexes Deck (11)
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1
Q

What is a reflex?

A

Rapid involuntary response to a stimulus

2
Q

What are the general functions of reflexes

A

Protective - limb withdrawal/cough reflex
Postural control - walking
Homeostasis - blood pressure stability

3
Q

What is the chain of a reflex arc?

A
Receptor
Afferent
Integration <=> CNS
efferent
effector
4
Q

What are the neuronal components of a reflex?

A

Receptors
Afferents - sensory neurones
Interneurones - modulation of information in and out
Efferents - (If somatic) innervate muscles
Effectors - Carry out the response

5
Q

What are interneurones?

A

Found in the CNS and ENS
They modulate the information coming in and out and tell the brain what is happening

Enable us to overcome the reflex

6
Q

Give 2 examples of simple stretch (myotatic) reflexes

A

Posture - important for the adjustment of muscle contraction

Receptors - proprioceptors (muscle spindle and GTO)

7
Q

Explain the process of a myotatic reflex in muscle spindle

A
  1. Muscle is stretched
  2. Nerve endings are stretched (mechanoreceptors)
  3. Sensory afferent releases excitatory neurotransmitters
  4. More efferent activity
  5. ACh released at NMJ
  6. Muscle contraction causing a response
8
Q

What type of reflex arc is found in the muscle spindle?

A

Monosynaptic (1 synapse with no interneurone)

Afferent directly synapses with efferent

9
Q

Explain the process of a myotatic reflex in the golgi tendon organ

A
  1. Increased contraction stretches tendon
  2. GTO activation increases
  3. Increased sensory activity
  4. Increased inhibition of neurone firing
  5. Decreased efferent activity
  6. Muscle no longer contracts
10
Q

What type of reflex arc is found in the golgi tendon organ?

A

Polysynaptic reverse myotatic reflex

11
Q

What is the purpose of a myotatic reflex?

A

Prevents muscle damage by tearing

Prevents muscle damage by overworking

Fine control of muscle tension.