A 56-year-old woman with a history of hyperlipidemia and hypeension develops progressive, right renal aery stenosis. Over time, this patient’s right kidney is likely to demonstrate which of the following morphologic adaptations to paial ischaemia?
**Core Concept**
The patient's right kidney is experiencing chronic hypoperfusion due to progressive right renal artery stenosis, leading to ischemia. This results in a cascade of cellular and molecular adaptations to maintain renal function.
**Why the Correct Answer is Right**
Chronic ischemia triggers the activation of various signaling pathways, including the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system. These pathways stimulate the release of vasoconstrictors, such as angiotensin II and norepinephrine, which further reduce renal blood flow. In response, the kidney undergoes a process called hypertrophy, characterized by an increase in cell size and protein synthesis. This adaptation enables the kidney to maintain its function despite the reduced blood flow.
**Why Each Wrong Option is Incorrect**
**Option A:** Atrophy is a reduction in cell size and protein synthesis, typically seen in acute or severe ischemia, not chronic hypoperfusion.
**Option B:** Hyperplasia is an increase in cell number, often seen in response to growth factors or hormonal stimuli, not ischemia.
**Option C:** Dysplasia refers to abnormal cell growth and development, typically seen in congenital or developmental disorders, not chronic ischemia.
**Clinical Pearl / High-Yield Fact**
The kidney's ability to adapt to chronic ischemia is a key factor in the development of hypertension, as the RAAS system is activated, leading to vasoconstriction and sodium retention.
**Correct Answer: C. Atrophy is incorrect. The correct answer is not provided as it is not in the options. However, if the options were:
**Correct Answer: D. Hypertrophy.**