Which of the following carry the pulses from the brain or spinal cord to the muscles?
A
Mixed nerves
✓
Motor nerves
C
Sensory nerves
D
All of the above
Answer
Correct option: B.
Motor nerves
A motor nerve is a nerve that carries information from central nervous system or spinal nerves to the effector organ or gland to give response to the stimulus.
Which of the following is regarded as a unit of nervous tissue?
A
Axons
B
Dendrites
✓
Neurons
D
Myelin sheath
Answer
Correct option: C.
Neurons
A neuron is the structural and functional unit of the nervous system. Neurons are similar to other cells in the human body in a number of ways, but there is one key difference between neurons and other cells. Neurons are specialized to transmit information throughout the body.
Wax secreting gland present in the ear canal is called:
A
Sweat gland.
B
Prostate gland.
C
Cowper’s gland.
✓
Ceruminous gland.
Answer
Correct option: D.
Ceruminous gland.
Ear canal is lined by hairy skin and ceruminous glands $($wax glands$).$ These $–$ glands secrete a waxy substance cerumen $($ear wax$)$ which prevents the foreign bodies entering the ear.
Parkinson’s disease $($characterized by tremors and progressive rigidity of limbs$)$ is caused by degeneration of brain neurons that are involved in movement control and make use of neurotransmitter.
Four healthy people in their twenties got involved in injuries resulting in damage and death of a few cells of the following. Which of the cells are least likely to be replaced by new cells.
Animals possess nerve network or nervous system to respond to their environment. But the single called Amoeba does not possesses any nerve cell, So, How it come to know whether a particle it encounters is a grain or sand and not its dinner?
Organ of corti are present on the sensory ridge of basilar membrane of cochlea. Hair cells which act as auditory receptors are present in organ of corti.
A synapse is a structure, that permits a neuron to pass an electrical or chemical signal to another neuron. These chemical or electrical signals can be inhibitory or stimulatory or conducting in nature.
In a similarity with photographic camera, retina acts as:
A
Shutter
B
Lens
C
Diaphragm
✓
Film
Answer
Correct option: D.
Film
In a photographic camera, image is formed on the film. Similarly, in eye, image is formed on the retina which is the light sensitive surface in the eye. The light rays enter the eye through an aperture called pupil. The eye lens which is biconvex, focus the light rays on the retina and an image is formed. Both the camera and eye have the ability to regulate the amount of light for image formation.
During resting state, fluid outside axon contains.
✓
Low concentration of $K^+$
B
Low concentration of $Na^+$
C
Low concentration of $Cl^-$
D
High concentration of $Cl^-$
Answer
Correct option: A.
Low concentration of $K^+$
During resting state $($when neuron is not conducting any impulse$),$ axoplasm inside the axon contains high concentration of $K^+$
The fluid outside axon contains low concentration of $K^+$.
The rods contain a purplish red protein called the rhodopsin. It is a photosensitive compound in eye that is composed of opsin $($a protein$)$ and retinal $($an aldehyde of vitamin$-A)$, whereas vitamin$-B, C$ and $D$ not directly related with vision.