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.
Neurotransmitters are molecules that fit like a lock and key into a specific receptor. The receptor is located on the next cell in the line. Therefore, nerve impulses cannot travel in the opposite direction, because nerve cells only have neurotransmitter storage vesicles going one way, and receptors in one place.
Given below is a table comparing the effects of sympathetic and parasympathetic nervous system
for four feature (a-d). Which one feature is correctly described
| Feature | Sympathetic nervous system | Parasympathetic nervous system |
| a) Salivary glands | Stimulate Secretion | Inhibit Secretion |
| b) Pupil of the eye | Dilate | Constricts |
| c) Heart rate | Decreases | Increases |
| d) Intestinal peristalsis | Stimulates | Inhibits |
A person is wearing spectacles with concave lenses for correcting vision. While not using the glasses, the image of a distant object in his case will be formed
on the blind spot
behind the retina
in front of the retina
on the yellow spot
The total number of nitrogenous bases in human genome is estimated to be about
3.5 million
35 thousand
35 million
3.1 billion.
Cerebrospinal fluid is present
beneath the pia mater
between piamater and arachnoid
between arachnoid and duramater
between duramater and cranium
The dendrite carries impulses
towards the cyton
away from cyton
across the body
from one neuron to another
Examine the diagram of the two cell types A and B given below and select the correct option
A B
Cell A is the rod cell found evenly all over retina
Cell A is the cone cell more concentrated in the fovea central is
Cell B is concerned with colour vision in bright light
Cell A is sensitive to low light intensities
Cochlea of mammalian internal ear is concerned with
hearing
balance of body posture
both (a) and (b)
perception changes of atmospheric pressure
A person who shows unpredictable moods, outbursts of emotion, quarrelsome behaviour and conflicts with others is suffering from
borderline personality disorder (BPD)
mood disorder
addictive disorder
schizophrenia.
