Nokea
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.
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Cortisol is produced by the:
- A. adrenal cortex
- B. adrenal medulla
- C. anterior pituitary
- D. pancreas
Correct Answer: A
Rationale: The correct answer is A: adrenal cortex. Cortisol is a glucocorticoid hormone produced by the adrenal cortex. The adrenal cortex is responsible for the synthesis and secretion of cortisol in response to stress. The adrenal medulla produces catecholamines like adrenaline and noradrenaline, not cortisol. The anterior pituitary produces adrenocorticotropic hormone (ACTH), which stimulates cortisol production by the adrenal cortex. The pancreas produces insulin and glucagon, not cortisol. Therefore, the adrenal cortex is the correct choice for the production of cortisol.
When blood Calcium level is elevated, the body is in a state of hypercalcemia. Which gland is responsible for secreting a hormone to return Ca2+ level to normal and therefore maintain homeostasis?
- A. Hypothalamus
- B. Pituitary
- C. Thyroid
- D. Parathyroid
Correct Answer: c
Rationale: The correct answer is D: Parathyroid. The parathyroid gland secretes parathyroid hormone (PTH) when blood calcium levels are elevated. PTH acts to increase calcium reabsorption in the kidneys, release calcium from bones, and enhance calcium absorption in the intestines, ultimately lowering blood calcium levels back to normal.
A: The hypothalamus plays a role in regulating body temperature, thirst, hunger, and circadian rhythms, but not in calcium homeostasis.
B: The pituitary gland secretes various hormones, but none specifically involved in regulating blood calcium levels.
C: The thyroid gland secretes thyroid hormones that regulate metabolism and growth, not calcium levels.
In the adrenal medulla:
- A. epinephrine is formed by the hydroxylation and decarboxylation of tyrosine
- B. 10% of the cells are the epinephrine-secreting type
- C. plasma norepinephrine levels are generally unchanged after adrenalectomy
- D. catecholamine t1/2 is 10 minutes in the circulation
Correct Answer: C
Rationale: Rationale for Choice C: Plasma norepinephrine levels are generally unchanged after adrenalectomy in the adrenal medulla because norepinephrine is mainly produced by postganglionic sympathetic nerve endings rather than the adrenal medulla. Adrenalectomy removes the adrenal gland, which primarily secretes epinephrine, not norepinephrine. Therefore, plasma norepinephrine levels would not be significantly affected by adrenalectomy.
Summary of other choices:
A: Incorrect. Epinephrine is formed from norepinephrine, not tyrosine, through methylation and hydroxylation.
B: Incorrect. The majority of cells in the adrenal medulla are epinephrine-secreting cells, not just 10%.
D: Incorrect. The half-life of catecholamines in the circulation is very short, around 2 minutes, not 10 minutes.
Estrogens and progesterone are produced by:
- A. the testes.
- B. the ovaries.
- C. the adrenal glands.
- D. the hypothalamus.
Correct Answer: B
Rationale: Estrogens and progesterone are primarily produced by the ovaries in females. The ovaries are the main reproductive organs responsible for the production of these hormones, essential for menstrual cycle regulation and pregnancy support. The correct answer is B because the ovaries are the key glands that synthesize and release estrogen and progesterone. Choices A, C, and D are incorrect because the testes primarily produce testosterone, the adrenal glands produce cortisol and adrenaline, and the hypothalamus is a brain region involved in hormone regulation, not hormone production.
Which group is incorrect?
- A. Hormones of the anterior pituitary gland: ACTH, prolactin, TSH, growth hormone
- B. Hormones of the posterior pituitary gland: ADH, oxytocin
- C. Steroids: cortisol, aldosterone, testosterone, epinephrine
- D. Secretions of the gonads: estrogen, progesterone, testosterone
Correct Answer: C
Rationale: The correct answer is C because epinephrine is not a steroid hormone. Steroids are synthesized from cholesterol and have a specific chemical structure, while epinephrine is a catecholamine. Cortisol, aldosterone, and testosterone are examples of steroid hormones, but epinephrine belongs to the class of catecholamines. Therefore, C is incorrect. A, B, and D are correct as they accurately list hormones produced by the anterior pituitary gland, posterior pituitary gland, and gonads respectively.