Spinal Reflexes

Question 1

Give an example of a stretch reflex

Answer 1

Patellar tendon/knee jerk reflex

Question 2

Where is the force transmitted in stretch reflex

Answer 2

Muscle fibres- more elastic than tendons, more stretch

Question 3

What nerves are activated in stretch reflex

Answer 3

1a afferenet sensory nerves
increases 1a afferents in dorsal horn

Question 4

Overview of stretch reflex

Answer 4

Force transmitted to muscle fibres
Activates 1a afferent sensory nerves
Increases no. of APs in 1a afferents

Question 5

What are the 3 types of sensory afferent connections

Answer 5

1. Contact of a-motoneurones- contraction of agonist
2. Reciprocal Inhibition
3. Afferent firing up dorsal columns to thalamus & somatosensory cortex

Question 6

What is reciprocal inhibition

Answer 6

Muscles use agonists and antagonists to move joints
Agonist contracts, Antagonist relaxes
Inhibitory interneurones decrease a-motoneurones to antagonist

Question 7

What nerves are activated in inverse stretch reflex

Answer 7

1b afferent nerves from GTO

Question 8

What monitors muscle tension

Answer 8

Golgi tendon organ

Question 9

What does inverse stretch reflex cause

Answer 9

inhibitory interneurones to agonist
Excitory neurones to antagonist muscle
Info abt muscle tension to somatosensory cortex

Question 10

What is the flexor/withdrawal reflexes

Answer 10

Uses info from pain receptors
Withdraw part of body affected by pain stimulus towards body

Question 11

What does an increase in AP in nocireceptors cause

Answer 11

1. Increase activity in flexor muscles
2. Antagonist extensors inhibited
3. Other excitory interneurones Excite contralateral extensors
4. Inhibitory neurones inhibit contralateral flexors

Question 12

What is the fastest reflex

Answer 12

Stretch reflex

Question 13

Can reflex be overriden

Answer 13

Yes