Question 1

Alpha and beta receptors are the two primary subcategories of:&#10;A)muscarinic cholinergic receptors.&#10;B)nicotinic cholinergic receptors.&#10;C)dopamine receptors.&#10;D)5-hydroxytryptamine (serotonin)receptors.&#10;E)adrenergic receptors.

Accepted Answer

Alpha and beta receptors are both subtypes of adrenergic receptors, which respond to the neurotransmitter epinephrine (adrenaline) and norepinephrine (noradrenaline). Muscarinic and nicotinic receptors are subtypes of cholinergic receptors, which respond to the neurotransmitter acetylcholine. Dopamine receptors are a separate category that respond to the neurotransmitter dopamine. Finally, 5-hydroxytryptamine (serotonin) receptors respond to serotonin.

Question 2

In most peripheral tissues,sympathetic postganglionic neurons release ____ that binds directly to ____ receptors.&#10;A)epinephrine;adrenergic&#10;B)epinephrine;cholinergic&#10;C)norepinephrine;adrenergic&#10;D)norepinephrine;cholinergic&#10;E)acetylcholine;adrenergic

Accepted Answer

Sympathetic postganglionic neurons release norepinephrine that binds directly to adrenergic receptors in most peripheral tissues. Epinephrine may also be released from the adrenal gland into the bloodstream in response to stress or exercise, but it mainly acts on beta-adrenergic receptors. Cholinergic receptors bind to acetylcholine, which is released by both the sympathetic and parasympathetic nervous systems. However, they are not typically activated by sympathetic postganglionic neurons in peripheral tissues.

Question 3

All preganglionic neurons and parasympathetic postganglionic neurons are said to be _____ in nature because of the presence of ______ at their respective synapses.&#10;A)adrenergic;norepinephrine&#10;B)cholinergic;norepinephrine&#10;C)adrenergic;acetylcholine&#10;D)cholinergic;acetylcholine&#10;E)adrenergic;epinephrine

Accepted Answer

All preganglionic neurons and parasympathetic postganglionic neurons are cholinergic in nature because they release acetylcholine at their respective synapses. Adrenergic neurons release norepinephrine or epinephrine as their neurotransmitter. Therefore, options A, B, and E are incorrect.

Question 4

A drug that affects nicotinic cholinergic receptors will affect activity in both divisions of the autonomic nervous system (ANS)because:&#10;A)nicotinic cholinergic receptors are found on all organs and tissues innervated by the ANS.&#10;B)nicotinic cholinergic receptors are located at the junction between preganglionic and postganglionic neurons in both the sympathetic and parasympathetic pathways.&#10;C)both divisions of the ANS affect peripheral tissues by releasing epinephrine onto those tissues.&#10;D)all the above&#10;E)none of the above

Accepted Answer

Nicotinic cholinergic receptors are located at the junction between preganglionic and postganglionic neurons in both the sympathetic and parasympathetic pathways, so a drug that affects these receptors will affect activity in both divisions of the ANS. Nicotinic cholinergic receptors are not found on all organs and tissues innervated by the ANS, and both divisions of the ANS do not necessarily affect peripheral tissues by releasing epinephrine onto those tissues.

Question 5

A drug that inhibits muscarinic cholinergic receptors will selectively:&#10;A)increase sympathetic responses on peripheral tissues.&#10;B)decrease sympathetic responses on peripheral tissues.&#10;C)increase parasympathetic responses on peripheral tissues.&#10;D)decrease parasympathetic responses on peripheral tissues.&#10;E)increase responses in all tissues innervated by the autonomic nervous system.

Accepted Answer

Muscarinic cholinergic receptors are mainly found in the parasympathetic nervous system, and inhibition of these receptors would decrease parasympathetic responses on peripheral tissues. This would lead to an increase in sympathetic activity, as there would be less opposition from the parasympathetic nervous system.

Deck 18: Introduction to Autonomic Pharmacology