Kidneys

Definition

The kidneys are a pair of vital organs located in the lower back that play a crucial role in the body's overall health and functioning. They are responsible for filtering waste and excess water from the blood, regulating fluid and electrolyte balance, and maintaining acid-base balance, among other essential functions.

5 Must Know Facts For Your Next Test

1. The kidneys are responsible for filtering waste and excess water from the blood, a process known as ultrafiltration.
2. Kidneys play a crucial role in maintaining fluid and electrolyte balance in the body by regulating the reabsorption and excretion of water, sodium, and other ions.
3. The kidneys produce the hormone erythropoietin (EPO), which stimulates the production of red blood cells in the bone marrow.
4. Kidneys help regulate blood pressure by producing the enzyme renin, which is part of the renin-angiotensin-aldosterone system.
5. The kidneys are involved in the activation of vitamin D, which is essential for calcium absorption and bone health.

Review Questions

• Explain how the kidneys are involved in the structural organization of the human body.
  • The kidneys are a key component of the urinary system, which is one of the 11 major organ systems that make up the structural organization of the human body. The kidneys play a vital role in maintaining homeostasis by filtering waste and excess water from the blood, regulating fluid and electrolyte balance, and producing hormones that are essential for various bodily functions. Their location in the lower back and their intricate network of nephrons and blood vessels are integral to their ability to perform these critical tasks within the overall structure of the human body.
• Describe the kidneys' role as organs with secondary endocrine functions.
  • In addition to their primary function of filtering and regulating the body's fluids, the kidneys also have secondary endocrine functions. They produce the hormone erythropoietin (EPO), which stimulates the production of red blood cells in the bone marrow, and they activate vitamin D, which is essential for calcium absorption and bone health. The kidneys also play a role in blood pressure regulation through the production of the enzyme renin, which is part of the renin-angiotensin-aldosterone system. These endocrine functions demonstrate the kidneys' multifaceted role in maintaining overall physiological homeostasis.
• Analyze how the kidneys contribute to water balance and acid-base balance in the body.
  • The kidneys are critical for maintaining water balance and acid-base balance in the body. They regulate fluid levels by controlling the reabsorption and excretion of water, sodium, and other electrolytes. This ensures that the body's fluid compartments, such as blood and interstitial fluid, are properly balanced. Additionally, the kidneys play a key role in acid-base balance by excreting excess hydrogen ions and reabsorbing bicarbonate, which helps maintain the optimal pH level in the blood and other bodily fluids. Disruptions to these kidney functions can lead to various disorders, such as dehydration, edema, and acid-base imbalances, highlighting the kidneys' essential contribution to overall homeostasis.

Related terms

Nephron:

The basic functional unit of the kidney, consisting of a glomerulus and a renal tubule, which work together to filter blood and reabsorb essential substances.

Glomerular Filtration Rate (GFR):

The rate at which the kidneys filter blood through the glomeruli, a key indicator of kidney function.

Renal Cortex: The outer layer of the kidney, where the majority of the nephrons are located and where the initial filtration of blood takes place.