Nokea
In the pancreas, which are the cells that secrete insulin?
- A. Alpha
- B. Beta
- C. Delta
- D. None
Correct Answer: B
Rationale: The correct answer is B: Beta cells. Beta cells in the pancreas are responsible for secreting insulin. Insulin helps regulate blood sugar levels. Alpha cells (A) secrete glucagon, Delta cells (C) secrete somatostatin, both involved in glucose metabolism, but not insulin secretion. Choice D is incorrect as the pancreas does contain cells that secrete insulin.
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Enlargement of the thyroid gland:
- A. is called a goiter.
- B. causes Addisonian crisis.
- C. makes a person appear cushingoid.
- D. causes hypocalcemic tetany.
Correct Answer: A
Rationale: Step-by-step rationale for why choice A is correct:
1. Enlargement of the thyroid gland is known as a goiter.
2. A goiter can result from various conditions like iodine deficiency or thyroid disorders.
3. It is a common sign of thyroid dysfunction.
4. Goiter may or may not cause symptoms depending on the underlying cause.
5. Therefore, choice A is the correct answer.
Summary:
- Choice B (Addisonian crisis) is incorrect as it is associated with adrenal insufficiency, not thyroid enlargement.
- Choice C (cushingoid appearance) is incorrect as it is related to excess cortisol production, not thyroid enlargement.
- Choice D (hypocalcemic tetany) is incorrect as it is due to low calcium levels, not thyroid enlargement.
Concerning Alpha blockers, which of the following is CORRECT:
- A. Phentolamine is a selective Alpha1 blocker
- B. Alpha2 blockers decrease noradrenaline release
- C. Prazosin can block Alpha1 receptor only
- D. They decrease both BP and HR
Correct Answer: C
Rationale: Rationale:
C: Prazosin can block Alpha1 receptor only.
- Prazosin is a selective Alpha1 blocker, mainly used for hypertension.
- By blocking Alpha1 receptors, it reduces vasoconstriction and lowers blood pressure.
- Prazosin does not affect Alpha2 receptors, distinguishing it from non-selective Alpha blockers.
- Correct as it accurately describes Prazosin's mechanism of action.
Incorrect:
A: Phentolamine is a non-selective Alpha blocker, affecting both Alpha1 and Alpha2 receptors.
B: Alpha2 blockers increase noradrenaline release by inhibiting the negative feedback control.
D: Alpha blockers typically decrease blood pressure, but can increase heart rate due to vasodilation.
Name the structure that prevents food from entering the lungs?
- A. Pyloric sphincter
- B. Trachea
- C. Pharynx
- D. Epiglottis
Correct Answer: D
Rationale: The correct answer is D: Epiglottis. The epiglottis is a flap of tissue that covers the trachea during swallowing, preventing food from entering the lungs. When food is swallowed, the epiglottis closes off the trachea to ensure that the food goes down the esophagus into the stomach.
Incorrect choices:
A: The pyloric sphincter is a valve located between the stomach and the small intestine, regulating the flow of partially digested food.
B: The trachea is the windpipe that connects the larynx to the bronchi, allowing air to pass into the lungs.
C: The pharynx is the throat area where the pathways for both food and air cross, but it is the epiglottis that specifically prevents food from entering the lungs.
The most common second messengers for peptide hormones are ______ and _____.
- A. peptide hormones and calcium.
- B. calcium and glucose.
- C. cAMP and calcium.
- D. cAMP and sodium.
Correct Answer: C
Rationale: The correct answer is C: cAMP and calcium. Peptide hormones bind to their receptors on the cell surface, activating G-proteins which then trigger the production of cAMP as a second messenger. cAMP then further activates protein kinases to initiate various cellular responses. Calcium is also a common second messenger in peptide hormone signaling pathways, regulating processes like muscle contraction and gene expression. Choice A is incorrect because peptide hormones themselves are not second messengers. Choice B is incorrect as glucose is not a common second messenger for peptide hormones. Choice D is incorrect as sodium is not typically involved in peptide hormone signaling pathways.
Which sentences are correct?
- A. 1 only
- B. 1 and 2 only
- C. 1, 2 and 3
- D. 2 and 3 only
Correct Answer: B
Rationale: The correct answer is B: 1 and 2 only. Sentence 1 and 2 are correct because they are grammatically accurate and logically coherent. Sentence 3 is incorrect as it contains a grammatical error. The key is to analyze each sentence independently to determine its correctness based on grammar, clarity, and logical consistency. In this case, only sentences 1 and 2 meet the criteria, making B the correct choice.