Nokea
Alpha methyl dopa can produce:
- A. Inhibition of decarboxylase enzyme
- B. Increases renin
- C. Stimulation of Alpha2 receptor centrally
- D. Decreases blood pressure
Correct Answer: D
Rationale: Step 1: Alpha methyl dopa is a centrally acting antihypertensive medication.
Step 2: It is a prodrug that is converted to alpha-methyl norepinephrine in the brain.
Step 3: This metabolite stimulates alpha2 receptors in the brain, leading to decreased sympathetic outflow.
Step 4: Decreased sympathetic outflow results in decreased peripheral vascular resistance and ultimately decreases blood pressure.
Summary: Option D is correct because alpha methyl dopa decreases blood pressure by acting centrally on alpha2 receptors. Options A, B, and C are incorrect as alpha methyl dopa does not inhibit decarboxylase enzyme, increase renin, or stimulate alpha2 receptors centrally.
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Regarding carbohydrate metabolism:
- A. glucokinase is increased in starvation
- B. the breakdown of glycogen is called glycolysis
- C. the direct oxidative pathway involves the breakdown of glucose through triose
- D. the conversion of pyruvate to acetyl-CoA is irreversible
Correct Answer: D
Rationale: Correct Answer: D - The conversion of pyruvate to acetyl-CoA is irreversible because it is catalyzed by the enzyme pyruvate dehydrogenase. This step is a key regulatory point in carbohydrate metabolism as it commits pyruvate to enter the citric acid cycle for further energy production. Reversing this step would disrupt the normal flow of metabolic pathways.
Summary of other choices:
A: Glucokinase is not increased in starvation; it regulates glucose uptake in the liver.
B: The breakdown of glycogen is called glycogenolysis, not glycolysis which is the breakdown of glucose.
C: The direct oxidative pathway involves the breakdown of glucose through glycolysis, not triose.
Which of the following is a common cause of primary hypothyroidism?
- A. Graves' disease
- B. Hashimoto's thyroiditis
- C. Toxic multinodular goiter
- D. TSH secreting pituitary adenoma
Correct Answer: B
Rationale: The correct answer is B: Hashimoto's thyroiditis. This autoimmune condition is a common cause of primary hypothyroidism as it leads to inflammation and destruction of the thyroid gland, resulting in reduced production of thyroid hormones. Graves' disease (A) is actually a cause of hyperthyroidism, not hypothyroidism. Toxic multinodular goiter (C) is also associated with hyperthyroidism. TSH-secreting pituitary adenoma (D) causes secondary, not primary, hypothyroidism.
Which of the following hormones is produced by the adrenal cortex?
- A. Aldosterone
- B. Adrenaline
- C. Glucagon
- D. Calcitonin
Correct Answer: A
Rationale: The correct answer is A: Aldosterone. The adrenal cortex is responsible for producing aldosterone, a hormone that regulates blood pressure and electrolyte balance. Aldosterone is specifically produced in the zona glomerulosa layer of the adrenal cortex. Adrenaline (Choice B) is produced by the adrenal medulla, not the cortex. Glucagon (Choice C) is produced by the pancreas, not the adrenal cortex. Calcitonin (Choice D) is produced by the thyroid gland, not the adrenal cortex. Therefore, the correct answer is A because aldosterone is the hormone produced by the adrenal cortex.
A deficiency of dietary iodine:
- A. lowers plasma calcium levels.
- B. causes low blood volume and shock.
- C. decreases the synthesis of calcitonin.
- D. causes a goiter.
Correct Answer: D
Rationale: The correct answer is D because a deficiency of dietary iodine leads to an insufficient production of thyroid hormones, which can result in the enlargement of the thyroid gland, known as a goiter. This is due to the thyroid gland working harder to try to produce more hormones.
A, B, and C are incorrect because a deficiency of dietary iodine does not directly affect plasma calcium levels, blood volume, or the synthesis of calcitonin. These are functions that are primarily regulated by other hormones and factors in the body, not by iodine deficiency.
The structure leading to the stomach is called?
- A. Pharynx
- B. Epiglottis
- C. Oesophagus
- D. Larynx
Correct Answer: C
Rationale: The correct answer is C: Oesophagus. The oesophagus is the structure leading to the stomach that carries food from the mouth to the stomach through peristalsis. The pharynx (A) is the throat cavity, the epiglottis (B) is a flap that prevents food from entering the trachea during swallowing, and the larynx (D) is the voice box. Therefore, the oesophagus is the correct answer as it specifically functions to transport food to the stomach.