The Action of Parathormone in the Human Body
- A. Decreases blood sodium level
- B. Increases blood sodium level
- C. Decreases blood calcium level
- D. Increases blood calcium level
Correct Answer: D
Rationale: The correct answer is D: Increases blood calcium level. Parathormone is released by the parathyroid glands in response to low blood calcium levels. It acts to increase blood calcium levels by stimulating the release of calcium from bones, increasing calcium absorption in the intestines, and promoting calcium reabsorption in the kidneys. This helps to maintain proper calcium levels in the body. Choices A, B, and C are incorrect because parathormone does not have any direct effect on blood sodium levels and actually works to increase, not decrease, blood calcium levels.
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Which of the following is NOT synthesized in the pituitary gland?
- A. LH
- B. FSH
- C. ADH
- D. TSH
Correct Answer: C
Rationale: The correct answer is C: ADH. The pituitary gland consists of two parts: the anterior and posterior pituitary. ADH, also known as vasopressin, is synthesized in the hypothalamus and stored in the posterior pituitary. Therefore, it is not synthesized in the pituitary gland itself. LH, FSH, and TSH are all hormones synthesized and released by the anterior pituitary gland.
Which of the following is NOT a type of hormone stimulus?
- A. hormonal stimulus
- B. humoral stimulus
- C. neural stimulus
- D. receptor-mediated stimulus
Correct Answer: D
Rationale: The correct answer is D, receptor-mediated stimulus. Hormones can be stimulated by hormonal, humoral, or neural factors, but not directly by receptors. Hormonal stimulus involves other hormones triggering hormone release, humoral stimulus involves changing blood levels of ions or nutrients triggering hormone release, and neural stimulus involves direct nerve stimulation triggering hormone release. Receptor-mediated stimulus is not a recognized type of hormone stimulus because hormones do not directly respond to receptors in this context.
Which row gives the relative charges of electrons and neutrons?
- A. 0, 0
- B. 0, -1
- C. -1, 0
- D. -1, +1
Correct Answer: C
Rationale: The correct answer is C: -1, 0. Electrons have a charge of -1, while neutrons have no charge (0). This is because electrons are negatively charged particles, while neutrons are neutral. The other choices are incorrect because A: 0, 0 doesn't differentiate between the charges of electrons and neutrons, B: 0, -1 incorrectly assigns a charge to neutrons, and D: -1, +1 incorrectly assigns a charge to neutrons and doesn't represent the relative charges accurately.
On swallowing, the food leaves the mouth as a round mass called a bolus, into which structure does it pass?
- A. Pharynx
- B. Oesophagus
- C. Stomach
- D. Trachea
Correct Answer: B
Rationale: The correct answer is B: Oesophagus. After swallowing, the food bolus passes through the pharynx and enters the oesophagus, a muscular tube that connects the mouth to the stomach. The oesophagus helps transport the bolus to the stomach for further digestion. The pharynx is a common pathway for both food and air, but the food should not enter the trachea (D) as it leads to the lungs, causing choking. The stomach (C) is the final destination for the food bolus after passing through the oesophagus.
The actions of gastrin include all but:
- A. insulin secretion in response to a carbohydrate meal
- B. a trophic effect on colonic mucosa
- C. a trophic effect on gastric mucosa
- D. pepsin secretion
Correct Answer: A
Rationale: The correct answer is A because gastrin primarily stimulates gastric acid secretion and gastric mucosal growth but not insulin secretion. Gastrin acts on parietal cells to stimulate acid production and chief cells to release pepsinogen. Choice B and C are incorrect as gastrin does have a trophic effect on colonic and gastric mucosa, respectively. Choice D is also incorrect as gastrin stimulates pepsin secretion.