Nephron

Definition

A nephron is the functional unit of the kidney responsible for filtering blood, reabsorbing essential substances, and excreting waste products as urine. Each kidney contains approximately one million nephrons, which play a crucial role in maintaining homeostasis by regulating water, salts, and waste in the body. Nephrons ensure that the body’s internal environment remains stable despite changes in external conditions.

5 Must Know Facts For Your Next Test

1. Nephrons are composed of a renal corpuscle (containing the glomerulus and Bowman's capsule) and a renal tubule.
2. The nephron regulates blood volume and pressure through the reabsorption of water and sodium ions.
3. Each nephron is capable of producing urine independently, which contributes to overall kidney function.
4. Hormones such as aldosterone and antidiuretic hormone (ADH) influence nephron function by regulating sodium and water reabsorption.
5. The health of nephrons is critical; damage to them can lead to kidney disease and impaired osmoregulation.

Review Questions

• How do nephrons contribute to osmoregulation in the body?
  • Nephrons play a vital role in osmoregulation by filtering blood and adjusting the reabsorption of water and solutes. As blood flows through the glomerulus, excess water and waste products are filtered out, forming filtrate. The renal tubule then selectively reabsorbs essential nutrients and regulates water balance based on the body's needs, ensuring proper hydration levels and maintaining osmotic balance.
• Discuss the significance of the different segments of the nephron in maintaining electrolyte balance.
  • The different segments of the nephron have specialized functions that are crucial for maintaining electrolyte balance. The proximal convoluted tubule reabsorbs a significant amount of sodium, potassium, and bicarbonate from the filtrate. The loop of Henle plays a key role in creating a concentration gradient in the medulla, allowing for further water reabsorption. Lastly, the distal convoluted tubule fine-tunes electrolyte reabsorption under hormonal control, ensuring that the body maintains optimal levels of essential ions.
• Evaluate the impact of nephron damage on overall kidney function and homeostasis in the body.
  • Nephron damage significantly impacts overall kidney function and can lead to serious health issues such as chronic kidney disease or acute kidney injury. When nephrons are damaged, their ability to filter blood effectively is compromised, resulting in a buildup of waste products and imbalances in electrolytes and fluid levels. This disruption can cause systemic effects, including hypertension, edema, and metabolic imbalances, highlighting the importance of healthy nephron function for maintaining homeostasis.

Related terms

glomerulus: A network of tiny blood vessels within the nephron where blood filtration begins.

renal tubule: The part of the nephron that processes the filtrate, reabsorbing water and nutrients while secreting waste.

urine: The liquid waste product excreted by the kidneys, composed of water, salts, and metabolic waste.