In a neuron the concentration of intracellular potassium and extracellular sodium is in a

ratio of

1. 1:1

2. 30:1

3. 10:1

4. 3:1

Pick the odd-one out.

1. Nervous tissue : node of Ranvier

2. Ear: aqueduct of Sylvius

3. Bone : Volkman's canal

4. Eye: canal of Schlemm

Though sensitive to entire visible spectrum, the cones in the human eye show sensitivity to

1. blue colour

2. green colour

3. red colour

4. all of these.

Unipolar neurons are found only in

1. early embryos

2. olfactory epithelium

3. retina of the eye

4. spinal cord

Which of the following types of cells are found in retina ?

1. Neuroglial cell 

3. Schwann cell 

4. Amacrine cell

5. Purkinje cell

Which of the following minerals reduces the excitability of nerves and muscles?

1. Potassium

2. Sodium

3. Magnesium

4. Manganese

A frog has its brain crushed. But when pinched on the leg. The leg draws away. It is an

example of

1. neurotransmitter induced responsce

2. simple reflex

3. conditioned reflex

4. automated motor response.

Which of the following pesticides is an acetylcholinesterase inhibitor?

1. Aldrin

2. BHC

3. Endosulfan

4. Malathion

Identify the correct statement:

1. In amniotes last nerve is spinal accessory.

2. In non-amniotes last nerve is vagus.

3. Optic is shortest nerve.

4. Olfactory nerves has mixed fibres.

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.

1. on the blind spot

2. behind the retina

3. in front of the retina

4. on the yellow spot.