Unidirectional transmission of a nerve impulse through nerve fibre is due to the fact that
nerve fibre is insulated by a medullary sheath
sodium pump starts operating only at the cyton and then continues into the nerve fibre
neurotransmitters are released by dendrites and not by axon endings
neurotransmitters are released by the axon endings and not by dendrites.
D.
neurotransmitters are released by the axon endings and not by dendrites.
A synapse occurs where the axon of one neuron (the pre-synaptic neuron) meets the dendrite of another (the post-synaptic neuron). At the tip of the pre-synaptic axon is a button shaped swelling called a synaptic knob, inside which are numerous mitochondria and vesicles packed with a substance called a neurotransmitter which at the time of nerve impulse conduction diffuse across the space and bind to receptors in the membrane of the post-synaptic cell. This opens ion channels in the post-synaptic membrane resulting in a change in its membrane potential and in the consequent generation of a nerve impulse.
One of the examples of the action of the autonomous nervous system is
knee-jerk response
pupillary reflex
swallowing of food
peristalsis of the intestines
Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness?
Valium
Morphine
Hashish
Amphetamines
Which of the following is the part of mid brain of rabbit?
Diencephalon
Cerebrum
Corpora quadrigemina
None of the above
Now-a-days cornea transplantation is very popular. The reason is that it
is easy to preserve
transplanted very easily
can be easily obtained
does not link with blood supply and immune system
Cornea transplant in humans is almost never rejected. This is because
it is composed of enucleated cells
it is a non-living layer
its cells are least penetrable by bacteria
it has no blood supply
