Question

1. Which is the primary function absolute refractory period?

a) To return the membrane potential to the resting state

b) Allows the impulse to migrate only one way down the axon

c) To depolarize the neuron

d) To allow sodium to move into the cell

2. The Nodes of Ranvier

a) Increase absorption of Calcium by skeletal muscle cells

b) Store Potassium as a reserve for enhance neuron function

c) Speed transmission along the axon by allowing saltatory conduction

d) Enhance strength of skeletal muscle by increased Calcium release

3. Which is the primary function absolute refractory period?

a) To return the membrane potential to the resting state

b) Allows the impulse to migrate only one way down the axon

c) To depolarize the neuron

d) To allow sodium to move into the cell

4. Which of the following support cells does not belong to the Central Nervous System?

a) Astrocytes

b) Oligodendrocytes

c) Microglia

d) Ependyma

5. Which part of the brain is vital for causing short-term memories to become long-term memories?

a) Midbrain

b) Thalamus

c) Hippocampus

d) Pons

Answer 1

1) B. Allows the impulse to migrate only one way down the axon

Explanation: The absolute refractory period is the time after the excitatory phase during which a second Action potential can't be initiated, irrespective of the intensity of the stimulus. So, it doesn't allow a conduction in backward direction. Hence it only permits a one way stimulus transmission.

2) c) Speed transmission along the axon by allowing saltatory conduction.

Explanation: the whole axon is myelinated except at Nodes of Ranvier. So when an action potential travels through a nerve, it can jump from one Node of ranvier to the other node. This process is called saltatory conduction. It increases the speed of stimulus or signal transmission.

3) b) Allows the impulse to migrate only one way down the axon

Explanation: Same as question 1.

5) c) Hippocampus

Explanation: The long term memory is not specifically located in a particular area of the brain. It is encoded at various places in the cortex. The Hippocampus is the catalyst organism which helps in converting short term memory into long term memory.

Note: Q4 is incorrect as all the options i.e. microglia, ependyma, astrocytes and oligodendrocytes are found in CNS.