Good vision depends on adequate intake of carotene rich food.
Select the best option from the following statements:
i. | Vitamin A derivatives are formed from carotene |
ii. | The photopigments are embedded in the membrane discs of the inner segment |
iii. | Retinal is a derivative of Vitamin A |
iv. | Retinal is a light-absorbing part of all the visual photopigments |
1. (i),(iii) and (iv)
2. (i) and (iii)
3. (ii), (iii) and (iv)
4. (i) and (iv)
Choose the correct statement:
1. | Nociceptors respond to changes in pressure |
2. | Meissner's corpuscles are thermoreceptors |
3. | Photoreceptors in the human eye are depolarised during darkness and become hyperpolarised in response to the light stimulus |
4. | Receptors do not produce graded potentials |
Photosensitive compound in the human eye is made up of:
1. Opsin and Retinal | 2. Opsin and Retinol |
3. Transducin and Retinene | 4. Guanosine and Retinol |
In the mammalian eye, the ‘fovea’ is the center of the visual field, where?
1. high density of cones occur, but has no rods
2. the optic nerve leaves the eye
3. only rods are present
4. more rods than cones are found
A gymnast is able to balance his body upside down even in total darkness because of:
1. cochlea
2. vestibular apparatus
3. tectorial membrane
4. the organ of Corti
Which one of the following statements is not correct?
1. | Retinal is the light-absorbing portion of visual photo pigments |
2. | In retina, the rods have the photopigments rhodopsin while cones have three different photopigments. |
3. | Retinal is a derivative of Vitamin C |
4. | Rhodopsin is the purplish protein present in rods only. |
Parts A, B, C and D of the human eye are shown in the diagram. Select the option which gives correct identification along with its functions/characteristics:
1. | B-blind spot has only a few rods and cones |
2. | C-aqueous chamber reflects the light which does not pass through the lens |
3. | D-choroid- its anterior part forms the ciliary body |
4. | A-retina - contains photoreceptors rods and cones |
Which part of the human ear plays no role in hearing as such but is otherwise very much required?
1. Eustachian tube
2. Organ of Corti
3. Vestibular apparatus
4. Ear ossicles
A person entering an empty room suddenly finds a snake right in front on opening the door. Which one of the following is likely to happen in his neurohormonal control system?
1. | Sympathetic nervous system activated releasing epinephrine and norepinephrine from adrenal medulla |
2. | Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse |
3. | Hypothalamus activates the parasympathetic division of the brain |
4. | Sympathetic nervous system is activated releasing epinephrine and norepinephrine from the adrenal cortex |