Nokea
The action of acetylcholine is very short due to:
- A. Rapid hepatic metabolism
- B. Reuptake by nerve endings
- C. Binding to plasma proteins
- D. Hydrolysis by cholinesterase enzyme
Correct Answer: D
Rationale: The correct answer is D: Hydrolysis by cholinesterase enzyme. Acetylcholine is broken down by cholinesterase enzyme into choline and acetate, leading to the termination of its action. Rapid hepatic metabolism (A) is not the primary mechanism for acetylcholine breakdown. Reuptake by nerve endings (B) refers to reuptake of neurotransmitters, not breakdown. Binding to plasma proteins (C) does not affect the duration of acetylcholine action.
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A patient is admitted to the medical unit with possible Graves' disease (hyperthyroidism). Which assessment finding supports this diagnosis?
- A. Periorbital edema
- B. Bradycardia
- C. Exophthalmos
- D. Hoarse voice
Correct Answer: C
Rationale: Exophthalmos, or bulging eyes, is a common and distinguishing feature of Graves' disease, a form of hyperthyroidism.
All are characteristics of smooth muscle, except?
- A. Usually forms 2 layers at right angles to each other
- B. Utilizes troponin to help initiate muscle contraction
- C. Contains no striations
- D. Action potentials travel between muscle fibers quickly via tight junctions
Correct Answer: b
Rationale: The correct answer is B because smooth muscle does not utilize troponin to help initiate muscle contraction. Instead, smooth muscle contraction is regulated by calcium-calmodulin complex.
A: True - Smooth muscle usually forms 2 layers at right angles to each other.
C: True - Smooth muscle contains no striations.
D: False - Action potentials in smooth muscle travel slowly via gap junctions, not tight junctions.
The growth hormone produced by the pituitary gland is known as _______.
- A. somatotropin
- B. prolactin
- C. luteinizing hormone
- D. follicle-stimulating hormone
Correct Answer: A
Rationale: The correct answer is A: somatotropin. The growth hormone produced by the pituitary gland is known as somatotropin.
- "Somato" refers to the body, indicating its role in regulating body growth.
- "Tropin" refers to stimulation, emphasizing its function in promoting cell growth and regeneration.
- Prolactin (B) is responsible for milk production.
- Luteinizing hormone (C) and follicle-stimulating hormone (D) are involved in reproductive functions, not growth regulation.
Which nerve is NOT involved in the efferent (motor) swallow reflex?
- A. trigeminal
- B. vagus
- C. facial
- D. hypoglossal
Correct Answer: B
Rationale: The correct answer is B: vagus. The efferent (motor) swallow reflex involves motor nerves that control swallowing muscles. The vagus nerve (cranial nerve X) is primarily responsible for the afferent (sensory) component of the swallow reflex, while the efferent component is carried out by other cranial nerves such as the glossopharyngeal (IX), facial (VII), and hypoglossal (XII) nerves. Therefore, the vagus nerve is not directly involved in the efferent motor response during swallowing. Trigeminal (V), facial (VII), and hypoglossal (XII) nerves play essential roles in the motor aspects of swallowing, making them incorrect choices.
Quinidine is a drug used for arrhythmias. One of its properties is strong postsynaptic alpha-adrenergic receptor blocking activity. What side effect would you expect as a result of this property?
- A. Absence or at least decrease of lacrimal and mucus secretions
- B. Dilated pupils that don’t constrict in bright light
- C. Reduced blood pressure, hypotension
- D. Skeletal muscle tremors
Correct Answer: C
Rationale: The correct answer is C: Reduced blood pressure, hypotension. Quinidine's strong postsynaptic alpha-adrenergic receptor blocking activity would result in decreased activation of these receptors, leading to vasodilation and reduced blood pressure, which can cause hypotension. Choice A is incorrect because lacrimal and mucus secretions are not directly affected by alpha-adrenergic receptor blocking. Choice B is incorrect as dilated pupils are more associated with alpha-1 adrenergic receptor blockade. Choice D is incorrect as skeletal muscle tremors are not a typical side effect of alpha-adrenergic receptor blocking.