L16

Question 1

what is a reflex

Answer 1

stereotyped motor responses to a sensory stimulus
- can adapt to best suit a given task
- occur automatically, prior to voluntary reaction to the stimulus

Question 2

what are the two things sensory receptors are involved in

Answer 2

1. providing kinesthetic sensations about movement and position
2. providing rapid responses to perturbations or disturbances of movement

Question 3

____ centers play an important role in modulating and adapting spinal reflexes (can even reverse them)

Answer 3

supraspinal centers

Question 4

T or F: reflexes are set according to the motor task

Answer 4

true

Question 5

3 ways to alter strength of spinal reflex

Answer 5

1. cell body of the alpha motor neuron
2. interneurons in reflex pathway
3. presynaptic connections to the sensory afferents

Question 6

what is the presynaptic magnitude proportional to

Answer 6

the amount of neurotransmitter released and location relative to the axon hillock

Question 7

how are EPSP/IPSP different that an action potential

Answer 7

they are local and graded (not propagated)
and not followed by a refractory period. EPSP’s can therefore summate

Question 8

can EPSP’s summate?

Answer 8

yes they can as they do not have a refractory period

Question 9

graded potentials can summate _______ to generate an AP in the ________.

Answer 9

temporally and post-synaptic neuron

Question 10

what does it mean to summate spatially in order to get an AP

Answer 10

by having graded potentials from many neurons it can influence the alpha motor neuron to fire

Question 11

explain lateral inhibition

Answer 11

areas in the cortex that laterally inhibits other regions so that you see specific MN activation

Question 12

what type of neural network is the with drawl reflex

Answer 12

divergence

Question 13

explain divergence/ withdrawal reflex if you were to step on a tack

Answer 13

• pain stimulation goes into the spinal cord from cutaneous receptor
  -inhibition of extensors will occur while excitation of the flexors occurs
• (divergence) we see the inhibition and excitation of different muscle groups
• since we also don’t want to fall over there will be an excitation to extensors reaction on the supporting leg and inhibition of the flexors
• everything is occurring without the brain stem