b) Describe the function of the renal/urinary system as a whole, including its role in regulating fluid and electrolyte balance in the body, including pH levels.
c) What is the most common cause of renal failure?
The renal or urinary system plays a crucial role in maintaining homeostasis in the body. Its primary functions include:
Filtration of Blood: The kidneys filter waste products, excess substances, and toxins from the blood, producing urine as a byproduct. This process helps to eliminate metabolic waste, such as urea, creatinine, and uric acid.
Regulation of Fluid Balance: The kidneys regulate the volume of body fluids by adjusting the amount of water excreted in urine. This is influenced by factors such as hydration status, blood pressure, and hormonal signals (e.g., antidiuretic hormone).
Electrolyte Balance: The renal system maintains the balance of electrolytes, including sodium, potassium, calcium, and phosphate. The kidneys can reabsorb or excrete these ions as needed to maintain optimal concentrations in the blood.
Acid-Base Balance: The kidneys help regulate the body's pH levels by excreting hydrogen ions and reabsorbing bicarbonate from urine. This process is vital for maintaining the acid-base balance, ensuring that the blood pH remains within a narrow range (approximately 7.35 to 7.45).
Blood Pressure Regulation: The kidneys play a role in regulating blood pressure through the renin-angiotensin-aldosterone system (RAAS). They can adjust blood volume and systemic vascular resistance, influencing overall blood pressure.
Erythropoiesis Regulation: The kidneys produce erythropoietin, a hormone that stimulates the production of red blood cells in the bone marrow in response to low oxygen levels in the blood.
Detoxification and Metabolism: The kidneys also participate in the detoxification of various substances and the metabolism of certain drugs and hormones.
Overall, the renal/urinary system is essential for maintaining the internal environment of the body, ensuring that fluid and electrolyte levels, as well as pH, remain stable and conducive to health.
The most common cause of renal failure is diabetes mellitus, particularly when it leads to diabetic nephropathy. Chronic high blood sugar levels can damage the blood vessels in the kidneys, impairing their ability to filter waste effectively. Other significant causes of renal failure include hypertension (high blood pressure), glomerulonephritis, and polycystic kidney disease. However, diabetes remains the leading cause, accounting for a substantial proportion of cases of end-stage renal disease (ESRD) requiring dialysis or kidney transplantation.