4 Flashcards Preview

locomotion > 4 > Flashcards

Flashcards in 4 Deck (11)
Loading flashcards...
1
Q

what is a reflex?

A
involuntary
centred on:
spinal cord (spinal nerves)
brainstem (cranial nerves)
monosynaptic circuit
rapid-short latency
2
Q

what are motor neurons activated by?

A

various brain regions (cortex)

various peripheral receptors (reflex)

3
Q

describe the monosynaptic reflex arc

A

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

4
Q

what are the components of a reflex pathway?

A
stimulus
receptor
afferent (sensory) neuron
synapse (transmitter rx)
efferent (motor) neuron
effector (eg. muscle)
response
5
Q

what are the receptors in tendon-jerk reflexes?

A

proprioceceptor endings
group la muscle afferents
homonymous motor neurons

6
Q

what are the receptors in cutaneous reflexes?

A

mechanoreceptor endings

nociceptor endings

7
Q

give 4 somatic relexes

A

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

8
Q

what is the protective function of somatic reflexes?

A

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

9
Q

describe somatic muscle loading

A

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

10
Q

describe jaw muscle loading

A

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

11
Q

describe the pharyngeal (gag) reflex

A

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