Segments of the Kidney
The kidney has a shape similar to that of a kidney bean and is a vital organ within the urinary system. The primary function of the kidneys is to eliminate waste products from the body significantly, filter blood before returning it to the heart, among other essential functions. The structure of the kidney comprises the following parts:
Nephrons
Nephrons are the fundamental units of the kidneys, playing a crucial role in blood filtration, nutrient metabolism, and waste elimination through filtered blood. Each kidney contains approximately one million nephrons, which include the following components:
- Renal Corpuscle: This component receives blood from the nephron and consists of two elements:
- Glomerulus.
- Bowman’s Capsule.
- Renal Tubules: This is a series of tubules that extends from Bowman’s Capsule to the collecting ducts. Each tubule is divided into parts:
- Proximal Convoluted Tubule: Responsible for reabsorbing water, sodium, and glucose.
- Loop of Henle: Engaged in the absorption of potassium, chloride, and sodium.
- Distal Convoluted Tubule: This section reabsorbs additional sodium while secreting potassium and acids.
Note: As fluids reach the end of the tubule, they become filled with urea, a byproduct of protein metabolism, and are part of the kidney structure.
Renal Cortex
The renal cortex is the outer region of the kidney, containing glomeruli and convoluted tubules. The edges of the renal cortex are surrounded by a layer of fatty tissue called the renal capsule, which works alongside the cortex to protect the kidney’s internal structures.
Renal Medulla
The renal medulla, the kidney’s internal tissue, houses the Loop of Henle and renal pyramids:
- Renal Pyramids: These are small structures containing the nephron tubules responsible for transporting fluid within the kidney, ultimately leading to urine formation.
- Collecting Ducts: At the end of each nephron lies a collecting duct within the renal medulla, where filtered fluids exit the nephron.
Renal Pelvis
Waste elimination occurs through the renal pelvis, a funnel-shaped cavity located deep within the kidney that channels fluid to the bladder. The renal pelvis consists of:
- Calyces: The initial part of the renal pelvis that collects fluid before it is transported to the bladder.
- Pelvis.
- Ureter: A muscular tube that propels urine to the bladder until it reaches capacity and is expelled from the body.