Nokea
Increased muscle mass with slowness of activity (Hoffman syndrome) is seen in:
- A. Acromegaly
- B. Myxoedema
- C. Pseudohypoparathyroidism
- D. Myotonia dystrophica
Correct Answer: A
Rationale: Acromegaly is a disorder caused by excessive growth hormone production by the pituitary gland in adults, leading to an increase in muscle mass (hypertrophy). Hoffman syndrome, characterized by increased muscle mass with slowness of activity, is a clinical feature often seen in individuals with acromegaly. The excessive growth hormone levels in acromegaly can cause acral growth, soft tissue swelling, and muscle hypertrophy, contributing to the characteristic features of the condition, including Hoffman syndrome. Therefore, the correct answer is Acromegaly.
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Myxoedema coma is characterized by:
- A. Hypertension
- B. Tachycardia
- C. Euthermia
- D. Hypoventilation
Correct Answer: B
Rationale: Myxoedema coma is a severe form of hypothyroidism that can lead to the slowing down of various body functions, including reduced heart rate (bradycardia). As the condition progresses and the body's metabolism becomes more depressed, one of the compensatory mechanisms is an increase in heart rate (tachycardia) to try to maintain adequate tissue perfusion. Therefore, tachycardia is a characteristic feature of myxoedema coma, rather than hypertension or euthermia which are not typically associated with this condition. Hypoventilation is also a common feature of myxoedema coma due to the decreased metabolic rate and respiratory drive.
The receptors for non-steroid peptide hormones are found on the ______.
- A. plasma membrane
- B. nuclear envelope
- C. mitochondria
- D. lysosomes
Correct Answer: A
Rationale: The receptors for non-steroid peptide hormones are typically found on the plasma membrane of target cells. These hormones are large or polar molecules that cannot easily diffuse through the cell membrane. Instead, they bind to specific receptors on the cell surface, initiating signaling pathways that eventually lead to changes within the cell. Once the peptide hormone binds to its receptor on the plasma membrane, secondary messenger systems are activated to relay the signal into the cell and initiate the appropriate cellular response. This distinct mechanism of action highlights the importance of the plasma membrane as the location of receptors for non-steroid peptide hormones.
Primary hyperaldosteronism is not featured by:
- A. Diastolic hypertension
- B. Paraesthesia
- C. Alkalosis
- D. Oedema
Correct Answer: B
Rationale: Primary hyperaldosteronism, also known as Conn's syndrome, is characterized by excessive production of aldosterone by the adrenal glands, leading to increased sodium reabsorption and potassium excretion in the kidneys. The typical features of primary hyperaldosteronism include hypertension (often systolic), hypokalemia, metabolic alkalosis, and oedema due to sodium retention. Paraesthesia, which refers to abnormal sensations such as tingling or numbness, is not a common feature associated with primary hyperaldosteronism.
Hormones are:
- A. biologically inert by themselves.
- B. used as an energy source
- C. incorporated as a structural moiety into another molecule
- D. always stored in secretory granules
Correct Answer: C
Rationale: Hormones are chemical messengers that are produced by various glands in the body and released into the bloodstream to signal and regulate the activity of specific target cells. Unlike energy sources that can be metabolized for energy production (like carbohydrates and fats), hormones are not typically used as an energy source themselves (Choice B). Hormones are typically not biologically inert by themselves (Choice A), as they have specific functions in regulating various physiological processes in the body. While some hormones may be stored in secretory granules before release, not all hormones are stored in this manner (Choice D). Additionally, hormones are not always released by exocytosis (Choice E), as some hormones can also be released through other mechanisms such as diffusion. The correct choice, therefore, is C: hormones are incorporated as a structural moiety into another molecule, as they bind to specific receptors on target cells to elicit a cellular response and regulate physiological functions.
Commonest enzymatic defect for development of congenital adrenal hyperplasia is:
- A. C-21 hydroxylase deficiency
- B. 3b dehydrogenase deficiency
- C. C-11 hydroxylase deficiency
- D. C-17 hydroxylase deficiency
Correct Answer: A
Rationale: C-21 hydroxylase deficiency is the most common enzymatic defect leading to the development of congenital adrenal hyperplasia (CAH). This enzyme is necessary for the synthesis of cortisol and aldosterone in the adrenal glands. When there is a deficiency in C-21 hydroxylase, the pathway is shifted towards the production of androgens instead of cortisol and aldosterone, leading to excess androgen production. This results in the characteristic features of CAH, such as ambiguous genitalia in females and virilization in both males and females. Other enzyme deficiencies listed in the choices can also lead to different types of CAH but are less common compared to C-21 hydroxylase deficiency.