Neuromuscular Reflex

Question 1

what is extrafusal

Answer 1

bulk of skeletal muscle fibres which generates force
innervated by a motoneuron

Question 2

what is intrafusal

Answer 2

remaining specialised fibres - muscle spindles
innervated by y motorneuron and sensory afferents

Question 3

what is sensory or motor provided group

Answer 3

sensory and motor innervation is provided by either the group la afferents or the group II afferents

Question 4

why do muscle spindles sense chnage

Answer 4

Muscle spindles sense changes and respond to changes in muscle length to return skeletal muscles toresting state after they have been used

Question 5

step by step abdominus rectus

Answer 5

Abdominus rectus is contracted to help us stand from sitting
Extrafusal (and intrafusal) fibres shorten
Sensory afferents (group Ia and II fibres) in the intrafusal fibres relay information to the α motoneuron in the spinal cord
Activation of the α motoneuron stimulates abdominus rectus to relax
Helpfully, at the same time as the α motoneuron is stimulated, the γ motoneuron is activated

Question 6

reflex arc consists of

Answer 6

sensory receptors
sensory afferents (Group la and II afferents)
interneurons in the spinal cord
motor efferents (a motoneurons)

Question 7

stretch myotatic reflex

Answer 7

Hit the patella tendon with the hammer
The stretched muscle spindles in the muscle detect that stretch
Send sensory information up the afferent fibre up to the spindle cord
Where they synapse alpha motor neuron is inhibited increasing firing frequency and causing contraction
At the time sensory afferent information synapse at different location synapses at interneuron inhibitory one inhibits activity afferent neuron (for the agonist muscle of the leg of semi tendonous

Question 8

Inverse Myotatic reflex

Answer 8

Active shorten (contraction) detected by the golgi tendon
Respond by sensing sensory information group 1v to the spinal
-
Synapse have two different interneuron inhibitory interneurons receive sesnory information relay information (decrease activation of alpha motor neuron) decrease firing frequency quadricep femerus to relax
Same time sensory group one on excitatory neuron) excites alpha motor of the antagonist causes the muscle to contract

Question 9

Flexion withdrawal reflex

Answer 9

1.-
Inhibitory interneuron causes a muscle to relax of sesnors in the compartment leg (so it can flex away from the danger)
Synpasing excitatory neuron synapses motor neuron of the flexor compartment of the leg (move away from the danger)
Inhibitory interneurons allows flexor of the unaffected leg to relax (at the same tie of sensory information)
Excitatory interneuron synapse alpha motor leg sensor contract so you don’t topple over