The pigment that gets oxidized/bleached/decomposed when exposed to light is:
1. retinol
2. retinoyl ester
3. rhodopsin
4. iodopsin

Receptor sites for neurotransmitters are present on
1.membranes of synaptic vesicles
2. pre-synaptic membrane
3. tips of axons
4. post-synaptic membrane

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.
I. The photo pigments 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 photo pigments.
1. (I) and (II)
2. (I), (III) and (IV)
3. (I) and (III)
4. (II), (III) and (IV)

Myelin sheath is produced by
1. Schwann cells and Oligodendrocytes
2. Astrocytes and Schwann cells
3. Oligodendrocytes and Osteoclasts
4. Osteoclasts and Astrocytes

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 stimulus
4. Receptors do not produce graded potentials

Photosensitive compound in human eye is made up of
1. Opsin and Retinal
2. Opsin and Retinol
3. Transducin and Retinene
4. Guanosine and Retinol

Destruction of the anterior horn cells of the spinal cord would result in loss of
1. sensory impulses
2. voluntary motor impulses
3. commissural impulses
4. integrating impulses

In 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

Injury localised to the hypothalamus would most likely disrupt
1. short term memory
2. coordination during locomotion
3. executive function, such as decision making
4. regulation of body temperature

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 photo pigment rhodopsin, while cones have three different photo pigments
3. Retinal is a derivative of vitamin-C
4. Rhodopsin is the purplish red protein present in rods only