4

Question 1

what is a reflex?

Answer 1

involuntary
centred on:
spinal cord (spinal nerves)
brainstem (cranial nerves)
monosynaptic circuit
rapid-short latency

Question 2

what are motor neurons activated by?

Answer 2

various brain regions (cortex)

various peripheral receptors (reflex)

Question 3

describe the monosynaptic reflex arc

Answer 3

receptor -> arc -> brainstem/spinal cord -> muscle

Question 4

what are the components of a reflex pathway?

Answer 4

stimulus
receptor
afferent (sensory) neuron
synapse (transmitter rx)
efferent (motor) neuron
effector (eg. muscle)
response

Question 5

what are the receptors in tendon-jerk reflexes?

Answer 5

proprioceceptor endings
group la muscle afferents
homonymous motor neurons

Question 6

what are the receptors in cutaneous reflexes?

Answer 6

mechanoreceptor endings

nociceptor endings

Question 7

give 4 somatic relexes

Answer 7

biceps jerk reflex
ankle jerk reflex
triceps jerk reflex
rectir abdominis reflex

Question 8

what is the protective function of somatic reflexes?

Answer 8

escape mechanism
prevent muscle overloading
prevention of inadvertent foreign body ingestion
digestive aid

Question 9

describe somatic muscle loading

Answer 9

receptor activated by stretch and contraction
afferent signals cause inhibition of motor neuron activation
inverse of stretch reflex
inverse of myotatic reflex
prevents overloading of muscle

Question 10

describe jaw muscle loading

Answer 10

no Golgi tendon organs in jaw muscles
bite force controlled by increasing loading PDL
afferents inhibit haw elevator muscle motor neurons
anaesthesia of molars increases max bite force

Question 11

describe the pharyngeal (gag) reflex

Answer 11

mass contraction of both sides of posterior oral & pharyngeal musculature
activation:mechanoreceptor afferent from posterior part of tongue/soft palate
stimulation of sensory fibres from CNIX
afferents terminate in caudal part of spinal trigeminal nucleus
X afferents terminate innervate muscles