Which of the following statements describes an active cellular membrane exchange process?

Correct Answer: A

Rationale: The correct answer is A. In active transport, energy is expended to move substances against their concentration gradient. Sodium moving out of cells and potassium moving into cells is an example of active transport because it requires energy to pump these ions across the cell membrane against their concentration gradients. Choices B, C, and D describe passive processes where substances move along their concentration gradients without the input of energy.

Correct Answer: D

Rationale: Women with breast cancer due to a BRCA1 gene mutation commonly have a triple-negative breast cancer subtype, which means they are negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). This subtype tends to be more aggressive and harder to treat. Choice A is incorrect as they are typically negative for HER2. Choice B is incorrect because they are usually negative for estrogen receptor. Choice C is incorrect as they are usually negative for progesterone receptor and HER2.

Correct Answer: A

Rationale: Truncal obesity with thin extremities is a classic manifestation of Cushing syndrome due to the redistribution of fat. Enlargement of face, hands, and feet is seen in conditions like acromegaly, not Cushing syndrome. Cachexia is a state of severe weight loss and muscle wasting, typically seen in conditions like cancer or advanced infections. Thick scalp hair is not typically associated with Cushing syndrome.

Correct Answer: D

Rationale: Macular degeneration is a condition that affects the macula, a part of the retina responsible for central vision. It is primarily caused by impaired blood supply to the macula, leading to cellular waste accumulation and ischemia. This results in the death of photoreceptor cells and ultimately vision loss. Choices A, B, and C are incorrect because macular degeneration is not related to the loss of lens accommodation, detachment of the retina, or increased intraocular pressure. The correct answer directly addresses the underlying pathophysiology of macular degeneration.

Correct Answer: B

Rationale: The correct answer is a 45-year-old woman who is obese and has a menstrual pattern consisting of periods of amenorrhea and infrequent periods. Obesity and prolonged exposure to estrogen unopposed by progesterone due to infrequent ovulation are significant risk factors for endometrial cancer. Choices A, C, and D do not directly correlate with the increased risk of endometrial cancer. Postmenopausal status alone (Choice A), overweight with hypertension (Choice C), and smoking (Choice D) are not the primary risk factors for endometrial cancer.

Correct Answer: A

Rationale: Psoriasis is the correct answer because it is a chronic inflammatory skin condition characterized by features such as angiogenesis (formation of new blood vessels), immune cell activation (especially T cells), and excessive keratinocyte proliferation. This results in the typical symptoms seen in psoriasis, such as red, scaly patches on the skin. Melanoma is a type of skin cancer arising from melanocytes, not characterized by the features mentioned. Atopic dermatitis is a different skin condition involving eczematous changes, not specifically associated with the described characteristics of psoriasis. Urticaria is a skin condition characterized by hives and does not involve the same pathophysiological processes as psoriasis.

Correct Answer: C

Rationale: Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by abdominal pain, bloating, and changes in bowel habits. While IBS can lead to symptoms like diarrhea or constipation, it typically does not cause anemia (choice A), is not generally associated with intestinal E. coli (choice B), and is not often associated with bloody diarrhea (choice D). However, IBS can indeed be associated with anxiety and/or depression (choice C) due to the gut-brain axis, a bidirectional communication system between the gut and the brain. This association is well-documented in IBS patients, highlighting the importance of considering psychological factors in managing the condition.

Correct Answer: B

Rationale: Most body fluids are located within cells in the intracellular space. While the extracellular space also contains body fluids, the majority is found within the cells. Intravascular space refers to fluids within blood vessels, and transcellular space includes fluids in compartments like cerebrospinal, pleural, and peritoneal cavities.

Correct Answer: C

Rationale: The correct answer is C: Complement, clotting, and kinin systems. These are the three main plasma protein inflammatory mediator systems. The complement system helps in inflammation and immune responses, the clotting system is involved in blood coagulation, and the kinin system regulates inflammation and blood pressure. Choice A is incorrect because interferon is not part of the plasma protein inflammatory mediator systems. Choice B is incorrect because the fibrinolytic system is not a primary inflammatory mediator system. Choice D is incorrect because acute phase reactants are not part of the plasma protein inflammatory mediator systems.