Final answer:
In hypovolemic shock, kidney and urinary changes include a significant decrease in urine output, increased renal reabsorption of sodium and water to conserve fluid, and a reduced glomerular filtration rate leading to higher blood urea levels. These changes are critical in the body's attempt to preserve blood volume and maintain vital functions, but they may lead to kidney failure if not addressed.
Step-by-step explanation:
Kidney and Urinary Changes in Hypovolemic Shock
The condition known as hypovolemic shock occurs when there is a significant loss of blood or body fluids, leading to inadequate blood flow to supply oxygen and nutrients to tissues. In the kidneys, this can cause drastic changes. One of the primary changes is a sharp decrease in urine output, often lower than 1 mL/kg body weight/hour, which is a serious sign of impaired kidney function. This is due to the body prioritizing the preservation of the remaining volume for vital organs.
Renal reabsorption of sodium and water increases, as the renin-angiotensin-aldosterone system becomes more active to conserve fluid. This leads to reduced water loss in urine. In addition, due to low blood pressure and decreased glomerular filtration rate (GFR), blood urea levels may rise, indicating a build-up of waste products normally excreted by the kidneys. This process is a compensatory mechanism aimed at restoring blood volume and pressure, but if hypovolemic shock continues unchecked, it can result in kidney failure and impairment of homeostatic functions.