Oxytocin is essential for:

Correct Answer: D

Rationale: Oxytocin is a hormone that plays a crucial role in both the initiation of labor (A) and the milk ejection reflex (C) in breastfeeding mothers. During childbirth, oxytocin helps to stimulate contractions of the uterus, which are necessary for labor to progress. After childbirth, oxytocin continues to be important in the production and release of milk. When a baby suckles at the breast, oxytocin is released, causing the milk to be ejected from the mother's mammary glands, facilitating breastfeeding. Thus, oxytocin is essential for both the initiation of labor and the milk ejection reflex.

Correct Answer: D

Rationale: Parathormone, also known as parathyroid hormone (PTH), is a hormone secreted by the parathyroid glands. Its primary function is to regulate calcium and phosphate levels in the blood. One of the main actions of parathormone is to increase the resorption of calcium from the bone. This means that PTH stimulates the osteoclasts in bone tissue to break down bone matrix, releasing calcium into the bloodstream. This helps to increase the levels of calcium in the blood when they are low. The other functions of parathormone include increasing calcium reabsorption in the kidneys and promoting the formation of active vitamin D, which enhances calcium absorption in the intestines.

Correct Answer: A

Rationale: Oxytocin is the drug of choice for controlling postpartum hemorrhage. Oxytocin is a hormone that stimulates uterine contractions, helping to prevent and control excessive bleeding after childbirth. It is given via an intravenous infusion or intramuscular injection to help the uterus contract and reduce bleeding by causing the smooth muscle of the uterus to contract. Oxytocin is preferred due to its effectiveness, safety profile, and established role in managing postpartum hemorrhage. Other medications like Methylergometrine, Dihydroergotamine, and Prostaglandin E2 may also be used in certain situations, but oxytocin is the first-line drug for this purpose.

Correct Answer: C

Rationale: While the combined estrogen-progestin oral contraceptive pill offers various health benefits, such as reducing menstrual blood loss, lowering the risk of fibrocystic breast disease, and decreasing the risk of endometrial carcinoma, it is important to note that it is associated with a slightly increased risk of myocardial infarction (heart attack) compared to non-users. This is particularly significant in women who have other risk factors for cardiovascular disease, such as smoking, hypertension, diabetes, or obesity. Overall, the cardiovascular risks should be carefully evaluated and discussed with a healthcare provider before initiating the use of the combined oral contraceptive pill, especially in women with existing cardiovascular risk factors.

Correct Answer: B

Rationale: The primary mechanism of action of the combined estrogen-progestin oral contraceptive pill is the suppression of FSH and LH release. Estrogen and progestin in the pill work together to inhibit the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland. By suppressing the release of FSH, the pill can prevent the development of a dominant follicle in the ovary. Without a dominant follicle, ovulation is less likely to occur. Additionally, the suppression of LH prevents the release of the mature egg from the ovary. Ultimately, by preventing ovulation, the combined pill effectively reduces the chances of fertilization and pregnancy.