Pharmacology Extra Q & A from text book Flashcards
- A 3-year-old child has been admitted to the emergency department having swallowed the contents of 2 bottles of a nasal decongestant. The active ingredient of the medication is a potent, selective α-adrenoceptor agonist drug. Which of the following is a sign of α-receptor activation that may occur in this patient?
- (A) Bronchodilation
- (B) Cardiac acceleration (tachycardia)
- (C) Pupillary dilation (mydriasis)
- (D) Renin release from the kidneys
(E) Vasodilation of the blood vessels of the skin
The answer is C. Mydriasis can be caused by contraction of the radial fibers of the iris; these smooth muscle cells have α receptors. All the other listed responses are mediated by β adrenoceptors
Mr Green is a 60-year-old man with poorly controlled hypertension of 170/110 mm Hg. He is to receive minoxidil. Minoxidil is a powerful arteriolar vasodilator that does not act on autonomic receptors. Which of the following effects will be observed if no other drugs are used?
(A) Tachycardia and increased cardiac contractility
(B) Tachycardia and decreased cardiac output
(C) Decreased mean arterial pressure and decreased cardiac contractility
(D) Decreased mean arterial pressure and increased salt and water excretion by the kidney
(E) No change in mean arterial pressure and decreased cardiac contractility
The answer is A. Because of the compensatory responses, a drug that directly decreases blood pressure through a decrease in peripheral vascular resistance will cause a reflex increase in sympathetic outflow, an increase in renin release, and a decrease in parasympathetic outflow. As a result, heart rate and cardiac force will increase. In addition, salt and water retention will occur.
Full activation of the parasympathetic nervous system is likely to produce which of the following effects?
(A) Bronchodilation
(B) Decreased intestinal motility
(C) Increased thermoregulatory sweating
(D) Increased pupillary constrictor tone (miosis)
(E) Increased heart rate (tachycardia)
The answer is D.
Parasympathetic discharge causes bronchial and intestinal smooth muscle contraction and bradycardia. Thermoregulatory (eccrine) sweat glands are innervated by sympathetic cholinergic fibers, not parasympathetic.
For this question, use the accompanying diagram. Assume that the diagram can represent either the sympathetic or the parasympathetic system.
Assuming the structure is part of the thoracolumbar system, norepinephrine acts at which of the following sites in the diagram?
(A) Sites 1 and 2
(B) Sites 3 and 4
(C) Sites 5 and 6
The answer is C.
Norepinephrine acts at presynaptic α2 regulatory receptors (site 5) and postsynaptic α1 adrenoceptors (site 6). It may be metabolized by enzymes outside the synapse or transported back into the nerve terminal.
For this question, use the accompanying diagram. Assume that the diagram can represent either the sympathetic or the parasympathetic system.
If the effector cell in the diagram is a pupillary constrictor smooth muscle cell, which of the following receptor types is denoted by structure 6?
(A) Alpha1 adrenoceptor
(B) Beta2 adrenoceptor
(C) M3 cholinoceptor
(D) Ng cholinoceptor
The answer is C.
The nerves innervating the pupillary constrictor muscle are postganglionic parasympathetic cholinergic nerves. The pupillary dilator muscle contains α1adrenoceptors.
Nicotinic receptor sites do not include which one of the following sites?
(A) Bronchial smooth muscle
(B) Adrenal medullary cells
(C) Parasympathetic ganglia
(D) Skeletal muscle end plates
(E) Sympathetic ganglia
The answer is A.
Both types of ganglia and the skeletal muscle neuromuscular junction have nicotinic cholinoceptors, as does the adrenal medulla (a modified form of sympathetic ganglionic neuron tissue). Bronchial smooth muscle contains muscarinic cholinoceptors and noncholinergic receptors.
Several children at a summer camp were hospitalized with symptoms thought to be due to ingestion of food containing botulinum toxin. Which one of the following signs or symptoms is consistent with the diagnosis of botulinum poisoning?
(A) Bronchospasm
(B) Cycloplegia
(C) Diarrhea
(D) Skeletal muscle spasms
(E) Hyperventilation
The answer is B.
Botulinum toxin impairs all types of cholinergic transmission, including transmission at ganglionic synapses and somatic motor nerve endings. Botulinum toxin prevents discharge of vesicular transmitter content from cholinergic nerve endings. All of the signs listed except cycloplegia indicate increased muscle contraction; cycloplegia (paralysis of accommodation) results in blurred near vision.
Which one of the following is the primary neurotransmitter agent normally released in the sinoatrial node of the heart in response to a blood pressure increase?
(A) Acetylcholine
(B) Dopamine
(C) Epinephrine
(D) Glutamate
(E) Norepinephrine
The answer is A.
When blood pressure increases, the parasympathetic system is activated and heart rate decreases. Acetylcholine is the transmitter at parasympathetic nerve endings innervating the sinus node (nerve endings of the vagus nerve).
Assume that the diagram below represents a sympathetic postganglionic nerve ending.
Which of the following blocks the carrier represented by “z” in the diagram?
(A) Amphetamine
(B) Botulinum toxin
(C) Cocaine
(D) Hemicholinium
(E) Reserpine
The answer is C.
The reuptake carrier “z” (also known as NET) transports norepinephrine back into the nerve ending after release and is blocked by cocaine.
Assume that the diagram below represents a sympathetic postganglionic nerve ending.
Which of the following inhibits the carrier denoted “y” in the diagram?
(A) Cocaine
(B) Dopamine
(C) Hemicholinium
(D) Reserpine
(E) Vesamicol
The answer is D.
The vesicular carrier “y” in the diagram transports dopamine and norepinephrineinto the vesicles for storage. It can be blocked by reserpine. Hemicholiniums and vesamicol block transporters in cholinergic nerves.
