Kidney

Definition

The kidney is a vital organ responsible for filtering blood, removing waste, and balancing electrolytes in the body. Each person typically has two kidneys, which play a key role in the excretory system by producing urine, regulating blood pressure, and maintaining overall fluid balance. The proper functioning of kidneys is essential for homeostasis and impacts multiple body systems, highlighting their importance in health and disease.

5 Must Know Facts For Your Next Test

1. Kidneys filter approximately 50 gallons of blood daily, producing about 1-2 quarts of urine.
2. Each kidney contains around a million nephrons that are responsible for the filtration process.
3. The kidneys help regulate electrolyte levels such as sodium, potassium, and calcium in the body.
4. Hormones produced by the kidneys, like erythropoietin, stimulate red blood cell production in the bone marrow.
5. Kidneys play a critical role in maintaining acid-base balance by excreting hydrogen ions and reabsorbing bicarbonate.

Review Questions

• How do the kidneys contribute to the regulation of fluid balance in the body?
  • The kidneys contribute to fluid balance by filtering blood and adjusting the amount of water reabsorbed into the bloodstream. They monitor hydration levels and can either conserve or excrete water accordingly. When the body is dehydrated, kidneys reabsorb more water, leading to concentrated urine, whereas when there is excess fluid, they excrete more water, resulting in diluted urine.
• Discuss the role of nephrons in kidney function and how they relate to waste excretion.
  • Nephrons are the functional units of the kidney that perform the essential tasks of filtering blood and excreting waste products. Each nephron includes a glomerulus for initial filtration and tubules for further processing. They regulate what is reabsorbed back into circulation or secreted into urine, thus playing a direct role in waste excretion and maintaining homeostasis within the body.
• Evaluate how kidney dysfunction can affect overall health and what systemic changes may occur as a result.
  • Kidney dysfunction can have widespread effects on overall health due to their central role in filtering waste and regulating bodily fluids. When kidneys fail to function properly, waste products build up in the bloodstream, leading to conditions such as uremia. Furthermore, electrolyte imbalances can disrupt heart rhythms and muscle function, while impaired fluid regulation can cause hypertension or edema. This systemic impact underscores why kidney health is critical for maintaining general well-being.

Related terms

Nephron: The basic functional unit of the kidney that filters blood and produces urine.

Glomerulus: A network of capillaries located at the beginning of each nephron where blood filtration occurs.

Ureter: The tube that carries urine from the kidney to the bladder for storage before excretion.