Phys Nervous System

Repolarisation during falling phase of action potential occurs because:

Both sodium and potassium channels are open allowing sodium to enter a neuron while potassium to leave the neuron

Inactivation gates of the voltage-gated sodium channels begin to open

Voltage-gated sodium channels open allowing sodium to enter a neuron

More potassium ions diffuse into the neuron that sodium ions diffuse out of it

Voltage-gated potassium channels open allowing potassium to leave the neuron

Which of the following statement is correct:

Potassium concentration gradient drives K+ into cell

Chloride concentration gradient drives Cl- out of cell

Calcium concentration gradient drives Ca2+ out of cell

Potassium concentration gradient drives K+ out of cell

Sodium concentration gradient drives Na+ out of cell

How is the intensity of a stimulus encoded as information transmitted to the central nervous system?

The frequency of action potentials transmitted to the central nervous system is greater for a stronger stimulus.

The amplitude of action potentials transmitted to the central nervous system is greater for a stronger stimulus.

The neurotransmitter released from an afferent neuron differs based on the intensity of the stimulus.

Different second-order neurons transmit information about stimuli of varying intensities.

Different efferent neurons transmit information about stimuli of varying intensities.

A feature of the enteric nervous system is that it:

Has its own sensory neurons.

Only contains motor neurons.

Uses sensory neurons in dorsal root ganglia.

Uses the same motor neurons as in the ventral spinal cord.

Lies between the liver and small intestine.

Which of the following endocrine glands is innervated by sympathetic preganglionic neurons?

Which of the following statement is not correct:

When action potential reaches the terminals Na+ ions enter into terminals and release neurotransmitter from synaptic vesicles

Once action potential starts, the upstroke depolarizes the next part of the axon, bringing that up to threshold and causing it to regenerate a new action potential at that site

The action potential regenerates as it propagates along axon and reaches the axon terminals with the same size and shape as at the axon hillock

The action potential is a very large electrical event ~ 100mV from its peak to undershoot

Action potential propagates faster along myelinated axons than unmyelinated

Which of the following statement is correct:

Each depolarization that reaches axon hillock will generate an action potential in a neuron

The greatest density of voltage-gated sodium channels is located in basal dendrites

When a neuron reach threshold, a negative feedback loop for opening sodium channels is established

When threshold is reached the membrane potential becomes less negative

When the stimulus reaches the axon hillock and depolarize the membrane to +50mV, an action potential will occur

Parasympathetic postganglionic neurons primarily release the neurotransmitter ________.

The autonomic nervous system innervates all effector organs and tissues except ________.

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