spinal relexes

Question 1

describe the basic reflex arc

Answer 1

receptor converts stimulus into action potentials
these fire to the spinal cord via afferents
uses integration system in the grey matter
can be poly or monosynaptic interneuron
then motor efferents to muscle or gland to respond to the stimulus

Question 2

define reflex

Answer 2

fast predictable automatic repose to a change in the environment or stimulus

Question 3

what by definition is a myotactic stretch reflex

Answer 3

detecting the change in length of the muscle - muscle spindle detects this

Question 4

what is the standard response of a myotactic stretch reflex

Answer 4

keeping the same muscle tone - resisting the stretch

Question 5

give an example as to why the myotactic stretch reflex is important (stretch)

Answer 5

important in posture - antigravity muscles need to keep tone

Question 6

what is the difference between the agonist and antagonist response in a pall tap reflex

Answer 6

agonist - muscle stretch detected by muscle spindles send a1 afferent to synapse and mono synapse with alpha motor neurone that goes back to the muscle where it came from and contracts ie quad muscle extends knee

antagonist - 1a afferent reach polysynpatuic pathway with internecine which inhibits the opposing muscle ie excite inhibitory interneuron which relaxes the mastering muscles

Question 7

what is the inverse myotactic reflex

Answer 7

golgi tendon organs detect increased tension which stops you lifting something you can’t and preventing harm

Question 8

describe the mechanism of the inverse myotactic reflex (tension)

Answer 8

in contraction gologi organs detect this and send AP along 1b afferents which excites inhibitory interneuron and inhibits a motor neurons (efferents) to the same muscle - decreased activity of the agonist muscle - stops overload

also indirect activation of motor neurones innervating the antagonistic muscle

Question 9

which spinal reflex arcs are ipsilateral

Answer 9

myotactic

inverse myotactic

Question 10

what stimulus is the cross extensor/flexor withdrawal reflex

Answer 10

noxious cuteness stimulation causes flexion withdrawal from the offending stimulus

Question 11

describe the mechanism of the flexor withdraw reflex

Answer 11

action potential travel from stimulus to a delta and c afferenerts to spinal cord
indirect (polysynaptic actiavtion) of ipsilateral flexors and inhibition fo ipsilateral extensors ie limb withdrawn from the pain

also indirect activation of contralateral extensors and inhibition of central;ateral flexors - mainatence of balance during reflex