Nokea
The neurotransmitter released at the end of most sympathetic nerve fibers is:
- A. Epinephrine
- B. Noradrenaline
- C. Acetylcholine
- D. Acetylcholinesterase
Correct Answer: B
Rationale: The correct answer is B: Noradrenaline. Sympathetic nerve fibers release noradrenaline as the primary neurotransmitter to activate the fight-or-flight response. Noradrenaline acts on adrenergic receptors to increase heart rate, blood pressure, and blood flow to muscles. Epinephrine (choice A) is also released in the sympathetic nervous system but mainly by the adrenal glands. Acetylcholine (choice C) is the primary neurotransmitter in the parasympathetic nervous system. Acetylcholinesterase (choice D) is an enzyme that breaks down acetylcholine and is not a neurotransmitter.
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The Glucagon is:
- A. accelerates the conversion of glycogen into glucose.
- B. slows down glucose formation from lactic acid.
- C. decreases the conversion of glycogen into glucose.
- D. speeds up protein synthesis within cells.
Correct Answer: A
Rationale: The correct answer is A because glucagon stimulates the breakdown of glycogen into glucose, increasing blood glucose levels. Glucagon does not slow down glucose formation from lactic acid (B), decrease glycogen conversion (C), or speed up protein synthesis (D). Glucagon's primary function is to raise blood glucose levels in response to low blood sugar levels.
What are two effects of hypokalemia on the endocrine system?
- A. Decreased insulin and aldosterone release
- B. Decreased glucagon and increased cortisol release
- C. Decreased release of atrial natriuretic factor and increased ADH release
- D. Decreased release of parathyroid hormone and increased calcitonin release
Correct Answer: C
Rationale: Hypokalemia can lead to decreased release of atrial natriuretic factor and increased ADH release as the body attempts to balance sodium and fluid levels.
The ovaries secrete which of the following hormones?
- A. Oestrogen
- B. Luteinising hormone
- C. Follicle stimulating hormone
- D. Oxytocin
Correct Answer: A
Rationale: The correct answer is A: Oestrogen. Ovaries secrete oestrogen, a key female sex hormone involved in the development of secondary sexual characteristics, regulation of the menstrual cycle, and maintenance of pregnancy. Luteinising hormone (B) and follicle stimulating hormone (C) are secreted by the pituitary gland to regulate ovarian function. Oxytocin (D) is produced by the hypothalamus and released by the pituitary gland for uterine contractions and milk ejection, not by the ovaries. Therefore, A is correct as ovaries primarily produce oestrogen.
Exemplify hormones secreted by the anterior pituitary.
- A. anti-diuretic hormone and oxytocin
- B. ACTH and insulin
- C. growth hormone and LH
- D. thyroxine and cortisol
Correct Answer: C
Rationale: The correct answer is C: growth hormone and LH. The anterior pituitary gland secretes these hormones. Growth hormone regulates growth, metabolism, and body composition, while LH (luteinizing hormone) plays a role in reproductive function.
A: Anti-diuretic hormone and oxytocin are produced by the posterior pituitary gland.
B: ACTH (adrenocorticotropic hormone) is secreted by the anterior pituitary, but insulin is produced by the pancreas.
D: Thyroxine is released by the thyroid gland, and cortisol is produced by the adrenal glands, not the anterior pituitary.
ACTH, TSH, and gonadotropins are:
- A. hypothalamic-releasing hormones.
- B. secreted by the neurohypophysis.
- C. “aimed at†the adrenal cortex.
- D. tropic hormones.
Correct Answer: D
Rationale: Step 1: ACTH, TSH, and gonadotropins are hormones that stimulate the secretion of other hormones.
Step 2: These hormones target specific endocrine glands, such as the adrenal cortex.
Step 3: Since these hormones stimulate the secretion of other hormones and target specific glands, they are classified as tropic hormones.
Step 4: Thus, the correct answer is D: tropic hormones.
Summary: A is incorrect as they are not hypothalamic-releasing hormones. B is incorrect as they are not secreted by the neurohypophysis. C is incorrect as they are not specifically aimed at the adrenal cortex.