Which primary neurotransmitter is released by postganglionic sympathetic neurons onto vascular smooth muscle to mediate vasoconstriction?
Answer and explanation
Correct answer: D. Norepinephrine (noradrenaline)
Most postganglionic sympathetic neurons release norepinephrine, which binds to alpha-1 adrenergic receptors on vascular smooth muscle to stimulate contraction (vasoconstriction). Parasympathetic postganglionic neurons and sympathetic preganglionic neurons release acetylcholine.
Practise more Human Physiology: Neurobiology, Endocrinology, and Organ Systems.
Free questions with an explanation for every one, and full timed Toelatingsexamen Arts & Tandarts België (Medical & Dental Entrance Exam) mock tests.
More Human Physiology: Neurobiology, Endocrinology, and Organ Systems questions
- What primarily maintains the negative resting membrane potential of approximately -70 mV in human neurons?
- What immediate ionic event triggers the rapid depolarisation phase of a neuronal action potential once the threshold potential is reached?
- Why is it physiologically impossible to elicit a second action potential in a neuron during the absolute refractory period?
- What structural feature enables saltatory conduction along myelinated axons in the peripheral nervous system?
- At a chemical synapse, what directly triggers the exocytosis of neurotransmitter-containing synaptic vesicles into the synaptic cleft?
- How is the action of acetylcholine terminated at the neuromuscular junction?