Reflexes

Question 1

Define reflex

Answer 1

Involuntary movement/action to a stimulus

Question 2

What is the plantar/ babinski reflex why do Babies who it

Answer 2

stroking of the outer side of a baby’s foot causes the toes to spread in an upward movement
myelination of their spinal cord tracts is not complete

Question 3

2 types of reflexes

Answer 3

somatic and autonmic

Question 4

5 components of a reflex arc

Answer 4

. receptor

2. sensory neuron
3. integration centre - either mono (sensory neuron interfacing straight up w. a motor via one synapse) or poly synaptic (sensory inter neuron motor neuron 2 or more synapses BTW interneurons only in CNS) region within CNS
4. motor neuron
5. effector - muscle fibre, gland etc.

Question 5

Why is testing reflexes important and what are the most commonly assesses ones

Answer 5

May indicate some sort of degenerations of a specific nervous system region

Stretch and tendon
Flexor / cross- extensor
Superficial
Ocular

Question 6

function of stretch and tendon reflex

Answer 6

smooth ordination of skeletal muscle
provide NS w propriosetive information to regulate joint position and movement in space- 2 types of information
length of muscles by muscle spindles
amount of tension within muscle sent from the Golgi tendon organs (TGOs) poly synaptic

Question 7

2 types of afferent endings in muscle spindles

Answer 7

Anulospiral - wrap around spindle, stimulate by rate and degree of stretch
Flower spray endings - small axons at ends of spindle only stimulated by degree of stretch

Question 8

What helps support the innovated muscle spindle endings

Answer 8

Gamma efferent fibres help maintain sensitivity

Question 9

What does stretching the muscle do

Answer 9

Activates muscle spindles sensory fibres detect and more action potentials are generated

Question 10

Purpose of alpha gamma coactivation and how it works

Answer 10

No stretching spindles and sensory endings generate no action potential so no sensory info to NS about the muscle.
so gamma and alpha (sensory neurons) innervate extrafusal and intrafusal muscle fibres at same time so some tension and therefore AP is maintained

Question 11

what happens when a muscle stretches

Answer 11

Muscle spindles activate and sensory neurons send a message to spinal cord

Question 12

what is reciprocal inhibition

Answer 12

when an antagonist muscle eg quad and hammie is reduced to help the other muscle oppose the stretch

Question 13

Q FOR L what are gamma and Alpha motor / sensory neurons why are they important

Answer 13

…

Question 14

what nervous tissue does the Patella knee jerk reflex assess

Answer 14

between and including L2 and L4 segments of SC

Question 15

What. happens after a muscle is stretched

Answer 15

The sensory neurons form a monosynaptic connecting with alpha motor Hurons which tell the muscle to interact at same time poly synaptic connection with interneurons that tell the antagonist muscle to relax (inhibit it) so it doesn’t resist the contraction of the other

Question 16

purpose of tendon reflexes and by what are they initiated

is it mono or poly synaptic reflex

Answer 16

prevent muscles from tearing due to excessive forces
initiated by Golgi tendon organs or GTOs (force sensors)
poly synaptic

Question 17

how does tendon reflexes work

Answer 17

contraction or passive stretch activates reflex, afferent impulses to SC, contracting muscle relaxes. antagonist muscle contracts (reciprocal activation)

Question 18

what is the flexor reflex stimulated by
why important
mono or poly synaptic

Answer 18

initiated by a painful stimulus
poly synaptic and ipsilateral
importnat for survival

Question 19

what is crossed extensor reflex

Answer 19

occurs the flexor reflex to maintain balance, eg. stepping on glass with right foot the reflex stimulates the eft to contract and maintain its balance while the right foot is pulled away
contralateral extensor reflex
INVOLVES FLEXOR REFLEX

Question 20

what is the h reflex and why is it measured in the specific way it is by researchers

Answer 20

basically the stretch reflex but stimulated through a electrical shock to the nerve rather than through the muscle to avoid testing the functionality of the muscle spindles but rather focus on the ability of the neurons

Question 21

two ocular reflexes

Answer 21

pupillary light - diameter of pupil in response to light

vesibulo-ocular reflex

Question 22

what is the vesibulo - ocular reflex

Answer 22

controls eye movement when the head moves equal and opposite to movement of the head so that images are continuously centred and within field of vision
fastest reflex in body at 5 mili seconds
tested by turning head really quickly

Question 23

what does plantar reflex test

Answer 23

tests integrity of spinal cord from L4 to S2

response in adults should be downward flexion of toes

Question 24

2 types of reflexes

Answer 24

somatic (skeletal muscle)

autonomic (smooth muscle, glands, cardiac muscle)

Question 25

2 sensory tools that aid stretch and tendon reflex

Answer 25

muscle spindles

Golgi tendon organs

Question 26

anatomy of muscle spindles

Answer 26

3-10 skeletal muscle fibres INTRAFUSAL and within a capsule
gamma effect fibres at end (intrafusal)

muscle fibres (extrafusal) innervated by alpha motor neurons

Question 27

what is mono and what is polysynaptic in knee jerk reflex

Answer 27

quadricep inhibition (stop stretching) is monosynaptic 
inhibition of hamstring is poly

RECIPROCAL INHIBITION

Question 28

stretch vs tendon reflex

Answer 28

stretch - contraction of stretched (mono), inhibition of antagonist (poly), initiated by muscle spindles, reciprocal inhibition, both poly and monosynaptic

tendon - relaxation of flexed, activation of antagonist, tearing due to excessive force, ignited by GTO, polysynaptic reflex, reciprocal activation