Multiple sclerosis is result of demyelization which
progresses to affect the brain, spinal cord, etc. due to the axon being the one
getting the damage on impact. The main principle around myelinated fibers are
because for motor control you need action potentials. When the axon is
myelinated that is how the action potentials are sent out and they in response
travel faster with the more myelin present. So as the myelin sheath gets
detreated the longer it will take for the motor neurons to counterpart with
their effector muscles, which results in the poor motor control as mentioned.
The difference in the first part of the question,
monosynaptic and polysynaptic reflexes, are that monosynaptic goes by the name
that there is only one synapse in the CNS with two neurons, meanwhile
polysynaptic is more that 3 types of neurons and more than 1 synapse. As well
we can note that for polysynaptic reflexes there will be a longer synaptic
delay due to the fact that there 2 or more synapses occurring.
An ipsilateral reflex
is a response that occurs on the same side of the stimulus meanwhile for
contralateral reflex the response happens on the opposite side of the body. To
go more into detail, for ipsilateral, the sensory nerves impulses go in to the
spinal cord and as well leave from the same side as their designated motor nerve.
And for the contralateral, notably what is seen is the crossed action since it
will be reaching the entry and exit form opposite sides.
Strokes by definition are when there is a certain part of
the brain that is being deprived from the typical blood flow. With this in
effect, the cells of the brain are going to die off due to the lack of oxygen
that is being restricted from them. There are multiple types of strokes, but
all follow the general guidelines of such. In this scenario, we can see that
the patient is right-sided weak, so learned before we know that the brain works
in “opposite” ways in such that the part of the brain that was affected was the
left side. To go into further detail since we know his muscle strengthens is
weak we can as well conclude that there was damage to the primary motor cortex since
body muscles are controlled by this area.