neurotransmitters

Which of these neurotransmitters is secreted by the adrenal medulla but not adrenergic neurons?

Epinephrine

Norepinephrine

Dopamine

None of these

QUESTION 7

Which of these is not correctly paired with its effects on the neuromuscular junction?

Botulinum toxin – blocks the release of ACh from presynaptic terminals, causing total blockade of neuromuscular transmission, paralysis of skeletal muscle,

Curare – competes with ACh for the nicotinic receptors on the motor end plate, decreasing the size of the EPP. When administered in maximal doses, curare causes paralysis and death

Neostigmine – prevent degradation of ACh in the synaptic cleft, and it prolongs and enhances the action of ACh at the motor end plate

Hemicholinium – Increases reuptake of choline into presynaptic terminal

QUESTION 2

Which of these accurately describes the effect of acetylcholine in neuromuscular impulse transmission?

Acetylcholine binds to a muscarinic receptor on the motor-end-plate

Binding of acetylcholine to its receptor on the motor-end-plate generates an action potential immediately

Binding of acetylcholine to its receptor on the motor-end-plate increases the permeability of the motor end plate to both Na + and K + .

Binding of acetylcholine to its receptor on the motor-end-plate increases the permeability of the motor end plate to both Na + but not K + .

QUESTION 8

Which of these statements is true about the cable properties of neurons?

The higher the membrane capacitance the smaller the time constant

The higher the membrane resistance the greater the time constant

Internal resistance, R i , is directly related to the ease of current flow in the cytoplasm of the nerve fiber.

All of these are true