Human Kidney Structure and Function

Kidney Structure

• The kidneys are two bean-shaped organs located in the lower back, one on each side of the spine.
• Each kidney is about 4-5 inches long and weighs about 0.25 pounds.

Kidney Function

• The kidneys filter waste and excess fluids from the blood.
• They regulate electrolyte levels, maintain acid-base balance, and regulate blood pressure.
• The kidneys also produce hormones that help produce red blood cells, promote bone health, and regulate blood pressure.

Nephrons

• The functional units of the kidneys are called nephrons.
• There are about 1 million nephrons in each kidney.
• Each nephron consists of:
  • Glomerulus: a cluster of capillaries that filter the blood.
  • Bowman's capsule: a double-layered sac that surrounds the glomerulus.
  • Renal tubule: a narrow tube where reabsorption and secretion occur.

Kidney Blood Flow

• The kidneys receive about 20% of the total cardiac output.
• Blood flows into the kidneys through the renal arteries and out through the renal veins.
• The kidneys have a unique blood supply system, with two capillary beds: the glomerular capillaries and the peritubular capillaries.

Kidney Functions in Regulation

• Blood pressure regulation: the kidneys regulate blood pressure through the renin-angiotensin-aldosterone system.
• Electrolyte balance: the kidneys regulate electrolyte levels, such as sodium, potassium, and calcium.
• Acid-base balance: the kidneys help maintain acid-base balance by regulating hydrogen ion levels.

Kidney Diseases and Disorders

• Acute kidney injury (AKI): sudden damage to the kidneys.
• Chronic kidney disease (CKD): gradual loss of kidney function over time.
• Kidney stones: small, hard mineral deposits that form in the kidneys.
• Kidney failure: the kidneys are no longer able to filter waste and excess fluids from the blood.

Kidney Structure

• Kidneys are two bean-shaped organs, each about 4-5 inches long and weighing 0.25 pounds, located in the lower back on either side of the spine.

Kidney Function

• Filter waste and excess fluids from the blood.
• Regulate electrolyte levels, maintain acid-base balance, and regulate blood pressure.
• Produce hormones that help produce red blood cells, promote bone health, and regulate blood pressure.

Nephrons

• Functional units of the kidneys, with about 1 million in each kidney.
• Each nephron consists of a glomerulus, Bowman's capsule, and renal tubule.
• Glomerulus: a cluster of capillaries that filter the blood.
• Bowman's capsule: a double-layered sac that surrounds the glomerulus.
• Renal tubule: a narrow tube where reabsorption and secretion occur.

Kidney Blood Flow

• Receive about 20% of the total cardiac output.
• Blood flows into the kidneys through the renal arteries and out through the renal veins.
• Unique blood supply system with two capillary beds: glomerular capillaries and peritubular capillaries.

Kidney Functions in Regulation

Blood Pressure Regulation

• Regulate blood pressure through the renin-angiotensin-aldosterone system.

Electrolyte Balance

• Regulate electrolyte levels, such as sodium, potassium, and calcium.

Acid-Base Balance

• Help maintain acid-base balance by regulating hydrogen ion levels.

Kidney Diseases and Disorders

• Acute kidney injury (AKI): sudden damage to the kidneys.
• Chronic kidney disease (CKD): gradual loss of kidney function over time.
• Kidney stones: small, hard mineral deposits that form in the kidneys.
• Kidney failure: the kidneys are no longer able to filter waste and excess fluids from the blood.