The anatomy of the kidney is intricate, designed to efficiently filter blood, remove waste, maintain electrolyte balance, and regulate blood pressure.
Each kidney is a bean-shaped organ, approximately the size of a fist, located on either side of the spine, just below the rib cage.
The kidneys are part of the upper urinary tract and play a crucial role in the body's urinary system.
Here are the realistic diagrams of kidney anatomy, detailed and scientifically accurate, illustrating the kidney's internal structure.
Here's a detailed overview of the kidney's anatomy:
External Anatomy
1. Location:
The kidneys are retroperitoneal organs, meaning they are located behind the peritoneum (a lining of the abdominal cavity).
They are situated on either side of the vertebral column; the right kidney is typically slightly lower than the left due to the presence of the liver.
2. Size and Shape:
Each kidney is roughly 12 centimeters (about 4.5 inches) long, 6 centimeters (2.5 inches) wide, and 3 centimeters (1.2 inches) thick, resembling a large bean.
3. Renal Capsule:
Surrounding each kidney is a tough, fibrous membrane called the renal capsule, which protects the kidney from trauma and infection.
4. Renal Hilum:
The medial indentation where the renal artery enters the kidney, and the renal vein and ureter exit.
It's essentially the doorway through which blood vessels and nerves enter and exit the kidney.
Internal Anatomy
1. Renal Cortex:
The outer layer of the kidney, which appears granular.
It contains the glomeruli (the initial filtering components), proximal and distal convoluted tubules, and blood vessels.
2. Renal Medulla:
The inner layer of the kidney, composed of 10 to 18 renal pyramids.
These pyramids are cone-shaped tissues that contain the loops of Henle and the collecting ducts.
The apex (tip) of each pyramid, called the renal papilla, points inward towards the renal pelvis.
3. Renal Columns:
Inward extensions of the cortical material that separate the renal pyramids.
They provide a structure through which the blood vessels can enter and exit the cortex.
4. Renal Pelvis:
A funnel-shaped space at the central part of the kidney.
It collects urine from the major calyces and funnels it into the ureter.
5. Calyces:
The renal pelvis is divided into two or three major calyces, each of which further divides into several minor calyces.
These cup-shaped structures enclose the tips of the renal pyramids and collect urine, draining it into the renal pelvis.
Blood Supply
Renal Arteries:
Branches from the abdominal aorta, delivering oxygenated, nutrient-rich blood to each kidney.
Renal Veins:
Drain deoxygenated, filtered blood from the kidneys back to the inferior vena cava.
The kidneys receive a high volume of blood flow, which is essential for filtration and excretion processes.
Microscopic Structure
Nephrons:
The functional units of the kidneys, numbering about 1 to 1.5 million per kidney.
Each nephron consists of a glomerulus (a small blood-filtering capillary bed) and a renal tubule, where the filtered blood is converted into urine.