Choose the derivative of the plant Foxglove (Digitalis):

Correct Answer: A

Rationale: The correct answer is A: Digoxin. Foxglove (Digitalis) is a plant known for containing cardiac glycosides, specifically digoxin. Digoxin is derived from the leaves of the Foxglove plant and is commonly used to treat heart conditions such as heart failure and atrial fibrillation. Strophantin K is a cardiac glycoside derived from the Strophanthus plant. Dobutamine is a synthetic catecholamine used as a cardiac stimulant. Amrinone is a phosphodiesterase inhibitor used for treating heart failure. These choices are incorrect as they are not derivatives of the plant Foxglove.

Correct Answer: C

Rationale: The correct answer is C: Phenylephrine. Phenylephrine is a synthetic vasoconstrictor that acts by stimulating adrenergic receptors, specifically alpha-adrenergic receptors, leading to vasoconstriction. Noradrenaline (A) and adrenaline (B) are endogenous catecholamines that also have vasoconstrictive effects but are not synthetic. Angiotensinamide (D) is not a synthetic vasoconstrictor and acts through a different mechanism involving the renin-angiotensin system. In summary, Phenylephrine is the correct choice as it is a synthetic vasoconstrictor with adrenomimetic effects, while the other options do not fit this description.

Correct Answer: D

Rationale: Thyroid stimulating hormone (TSH) regulates all the mentioned functions. 1. A: TSH stimulates iodine uptake by thyroid follicular cells for thyroid hormone synthesis. 2. B: TSH promotes the biosynthesis of iodothyroglobulin, a precursor of thyroid hormones. 3. C: TSH triggers the release of thyroid hormones into the bloodstream. Therefore, the correct answer is D as TSH regulates all these processes essential for thyroid hormone production and release. Other choices are incorrect as they do not encompass all the functions regulated by TSH.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C (Progesterone) is correct: 1. Progesterone is a major natural progestin produced by the corpus luteum in the ovaries. 2. It plays a crucial role in the menstrual cycle and maintaining pregnancy. 3. Estradiol (choice A), Estron (choice B), and Estriol (choice D) are all estrogens, not progestins. 4. Estradiol is a predominant estrogen in premenopausal women, while Estron and Estriol are less potent estrogens. 5. Therefore, the correct answer is choice C, Progesterone, as it is the primary natural progestin in the body.

Correct Answer: A

Rationale: The statement accurately describes the immune system, making choice A true. The immune system indeed consists of organs, tissues, cells, and cell products that distinguish self from nonself and combat harmful pathogens. Choice B is incorrect as the statement is true. Choice C is incorrect as it implies all choices are correct, which is not the case. Choice D is incorrect as the statement is true, so it is not "none."