Question

An action potential is
a. a reversal of the Na+ and K+ concentrations inside and outside the neuron.
b. the same size and shape at the beginning and the end of the axon.
c. initiated by inhibitory post synaptic graded potentials.
d. transmitted to the distal end of a neuron and cause release of neurotransmitter.
e. Both b and d are correct

2. Axonal transport refers to:
a. the release of neurotransmitter molecules into the synaptic cleft.
b. the use of microtubules to send secretions from the cell body to the axon terminal.
c. the transport of vesicles containing proteins down the length of the axon.
d. the movement of the axon terminal to synapse with a new postsynaptic cell.
e. Both b and c are correct

3. Which of the following neuron(s) is known to be a motor neuron?
a. Pseudounipolar.
b. Bipolar.
c. Anaxonic.
d. Muiltipolar.
e. Both a and b are correct/ Beide a en b is korrek.

4. 4. Which one of the following glial cells is responsible for the blood brain barrier?
a. Oligodendrocytes.
b. Astrocytes.
c. Microglia.
d. Ependymal cells.
e. Satellite cells.

5. Which one of the following glial cells is responsible for myelination in the central nervous system?
a. Oligodendrocytes.
b. Astrocytes.
c. Microglia.
d. Ependymal cells.
e. Satellite cells.

6. Calculate the equilibrium membrane potential for Na+ for an extracellular fluid concentration of 138 mM and an
intracellular fluid concentration of 16 mM.
a. -90 mV.
b. -84 mV.
c. -72 mV.
d. –63 mV.
e. +57 mV.

7. Which of the following will open mechanically gated ion channels?
a. Acetylcholine release
b. Pressure
c. Change in membrane potential
d. Pain
e. Temperature

8. Which ion channel(s) is / are open during the repolarisation phase of the action potential recorded in a neuron.
a. Na+
b. K+
c. Cl-
d. Ca++
e. Both a and b will open

9. Rank the following neurons for their speed of conduction from fastest to slowest:
a. Myelinated 20 µm diameter axon
b. Unmeylinated 20 µm diameter axon
c. Unmeylinated 200 µm diameter axon
a. a, b, c
b. a, c, b
c. c, b, a
d. b, c, a
e. c, a, b

10. If you place an electrode in the middle of an axon and artificially depolarise the cell above threshold, in which
direction will an action potential travel?

a. To the axon terminal
b. To the cell body
c. Both a and b are correct
d. In neither direction

Answer 1

1) d. transmitted to the distal end of a neuron and cause release of neurotransmitter.

Explanation : When action potential is transmitted to distal end of a neuron causes the release of neurotransmitter.

Action potential occurs due to influx of the sodium and efflux of the potassium.

2. e. Both b and c are correct

Explanations : axonal transport is the transport of the material through the axon using microtubules.

3.d. Muiltipolar.

Explanation : unipolar neurons are sensory

Bipolar neurons are interneuron.

Multipolar neurons are motor neuron.

4.b. Astrocytes

Explanation : Astrocytes form tight junction in the blood brain barriers.

5. a. Oligodendrocytes.

Explanation :Nervous tissue are composed of main conducting neurons and supporting Neuroglial cells.

Neuroglial cells are the supporting tissue present around the neurons. They provide support and nutrition. Some Neuroglial cells form myelin sheaths.

Neuroglial cells are of two types

1) Macroglial cells

These are further of three types

- oligodendrocytes which form myelin sheath in CNS

- epindymal CELLS which secrete CSF

- Astrocytes which support and provide nutrition to the neurons

- They also take part in Reuptake of neurotransmitter by reabsorption

2) Microglial cells

- These are phagocytic cells of the CNS