The kidneys are essential organs in the human body, performing a myriad of tasks that maintain homeostasis and overall health.
Anatomical Position and Dimensions
The kidneys are retroperitoneal organs positioned against the posterior abdominal wall on either side of the spine, roughly between the twelfth thoracic and third lumbar vertebrae. Each kidney is typically 10-12 cm long, 5-6 cm wide, and 3-4 cm thick, weighing about 150 grams.
Renal Cortex
The outermost region of the kidney is the renal cortex, a light-colored layer that encircles the renal medulla. It envelops the renal medulla and extends into the renal sinus, forming renal columns that separate the renal pyramids of the medulla.
The renal cortex contains renal corpuscles, comprising glomeruli and Bowman's capsules alongside the proximal and distal convoluted tubules of the nephrons. These structures are essential for filtration, reabsorption, and secretion processes, all of which contribute to urine formation.
Renal Medulla
The renal medulla lies deep into the renal cortex and consists of cone-shaped tissue masses called renal pyramids. The base of each pyramid faces the cortex, while the apices, termed renal papillae, point toward the renal pelvis.
The medulla contains the loops of Henle and the collecting ducts of the nephrons, which are crucial for concentrating urine by reabsorbing water and various ions. These processes help regulate the body's fluid and electrolyte balance.
Renal Pelvis
The renal pelvis is a funnel-shaped cavity located within the renal sinus. It collects urine from the renal pyramids through the minor and major calyces before directing it into the ureter.
Common Diseases
Renal Cortex Disease: Glomerulonephritis is an inflammation of the glomeruli within the renal cortex, often caused by an immune response. If untreated, it can lead to chronic kidney failure.
Renal Medulla Disease: Medullary Sponge Kidney is a disorder characterized by the formation of cysts in the medulla, leading to urinary tract infections and kidney stones.
Renal Pelvis Disease: Pyelonephritis is an infection of the renal pelvis and kidney, typically caused by bacteria. Symptoms include pain, fever, and frequent urination.
The internal anatomy of the kidney is a complex and intricate system, with each part playing a vital role in maintaining the body's overall health. Understanding these structures and their associated diseases is crucial for early detection and effective treatment. Regular medical check-ups and prompt attention to symptoms can significantly reduce the impact of kidney-related conditions.
In the frontal section, the kidney shows the renal cortex, renal medulla, and renal pelvis.
The outermost layer — the renal cortex — is characterized by its light red color and grainy texture.
The renal medulla is the inner, darker, reddish-brown section of cone-like tissue groups known as renal or medullary pyramids.
These pyramids, along with the renal cortex, form the parenchyma, which is the functional part of the kidney.
About eight extensions of the cortex, known as renal columns, separate these pyramids.
Each pyramid has a wide base facing the cortex and an apex called a renal papilla facing the renal hilum.
The papillae are encased by the minor calyces, which merge to form a major calyx.
The major calyces form two to three branches that merge to form a funnel-like tube called the renal pelvis.
The calyces continuously drain urine from the papillae, collecting and transferring it to the renal pelvis.
From the renal pelvis, the urine is transported to the ureter and finally to the bladder.
繁體中文
