A 29 year old married computer programmer is c/o 'something strange' going on in his scrotum. Last month he felt a lump in his left testis, and it is still there. He has had some aching in the left testis but denies pain with urination or intercourse. Denies fever, malaise, night sweats. His PMH consisted of groin surgery as a baby and a tonsillectomy as an adolescent. He eats a healthy diet, exercises, denies tobacco or drugs. On exam the penis is circumcised with no lesions. No lymphadenopathy. Palpation of his scrotum is unremarkable on the right but indicates a large mass on the left. Placing a finger through the inguinal ring on the right, you have the patient bear down. Nothing is felt. You attempt to place your finger through the left inguinal ring but cannot get above the mass. On rectal exam, his prostate is unremarkable. What disorder of the tests is most likely the diagnosis?

Correct Answer: B

Rationale: The correct answer is B: Scrotal hernia. The patient's presentation with a lump in the left testis, aching, and a large mass on the left side of the scrotum, along with the inability to pass a finger above the mass through the left inguinal ring, suggests a scrotal hernia. This is further supported by the fact that bearing down does not reveal anything on the right side, ruling out hydrocele and varicocele. Scrotal edema would present with more generalized swelling in the scrotum rather than a localized mass. So, the key findings here point towards a scrotal hernia as the most likely diagnosis.

Correct Answer: A

Rationale: Progesterone levels rise to their highest point between ovulation and the beginning of menstruation because this is the luteal phase of the menstrual cycle when the corpus luteum (formed from the ruptured follicle after ovulation) secretes progesterone. This hormone prepares the endometrium for implantation and maintains a potential pregnancy. Explanation for other choices: - B: Immediately before ovulation, estrogen levels are high, not progesterone. - C: Luteinizing hormone surge triggers ovulation, not directly related to progesterone rise. - D: The development of primary follicles is associated with estrogen, not progesterone.

Correct Answer: B

Rationale: Correct Answer: B - High levels of progesterone and estrogen during pregnancy suppress milk production. Rationale: 1. Progesterone and estrogen levels are high during pregnancy to maintain the uterine lining and support fetal development. 2. These hormones inhibit the action of prolactin, the hormone responsible for milk production. 3. As a result, the mammary glands are prevented from producing milk until after delivery when progesterone and estrogen levels drop. 4. Once these hormone levels decrease, prolactin can initiate milk production in response to the baby's demand for feeding. Summary of other choices: A: Levels of luteinizing hormone and follicle-stimulating hormone do not directly impact milk production during pregnancy. C: Alveolar cells of the breast may have some developmental changes during pregnancy, but it is not the primary reason for milk production post-delivery. D: Oxytocin is involved in milk ejection, not milk production, and its release is

Correct Answer: B

Rationale: The correct answer is B: Peptide or protein hormones have receptors on the cell membrane. These hormones are typically large molecules that cannot pass through the cell membrane, so they bind to receptors on the cell surface to initiate signal transduction pathways. This allows them to quickly and effectively communicate with target cells. A: They do not have longer half-lives than steroid hormones. Peptide hormones are usually rapidly degraded compared to steroid hormones. C: They do not have a slower onset of action than steroid and thyroid hormones. Peptide hormones can have rapid onset of action due to their signaling pathways. D: They can be stored in endocrine-producing glands, such as insulin being stored in pancreatic beta cells.

Correct Answer: B

Rationale: The correct answer is B: Ductus venosus. The ductus venosus carries oxygenated blood from the umbilical vein to the inferior vena cava, bypassing the liver. This blood has the highest Po2 among the choices because it is coming directly from the placenta, where oxygen exchange occurs. The other choices (A, C, D) carry deoxygenated blood or blood with lower oxygen content in the fetal circulation. The ductus arteriosus shunts blood from the pulmonary artery to the aorta, so it carries deoxygenated blood. The ascending aorta and left atrium receive mixed oxygenated and deoxygenated blood, not the highest Po2.