Final answer:
The human kidneys are bean-shaped with a concave side where the renal hilum is located for blood and urine flow. They are encapsulated by a renal capsule and feature an outer cortex, inner medulla, and renal pelvis. Nephrons, the microscopic functional units, facilitate blood filtration and urine production.
Step-by-step explanation:
Anatomical Features of the Human Kidney
The human kidney is a vital organ with complex anatomy. The organ is bean-shaped, possessing a convex and a concave side. The concave side features the renal hilum, which is the entry and exit site for the renal artery, the renal vein, and the ureter. The kidney is encapsulated by a tough fibrous tissue called the renal capsule, and is cushioned by protective layers of fat.
Internally, the kidney consists of several distinct areas. The outermost region is the renal cortex, followed by the inner medulla, and the deepest part, the renal pelvis. The medulla contains triangular structures known as renal pyramids and renal papillae. These are separated by renal columns, which serve both to divide the kidney into lobes and support vascular structures.
The microscopic functionality of the kidney is attributed to approximately 1.3 million nephrons per kidney, comprising Bowman's capsule, the glomerulus, proximal and distal convoluted tubules, and loop of Henle. The nephrons handle filtration and concentration of urine, which eventually travels through the collecting ducts to the calyces, renal pelvis, and then the ureter.
Additionally, each kidney is topped with an adrenal gland, which influences renal function through hormone production. The kidneys are located in the retroperitoneal space, protected by the ribs and surrounding muscle, and receive about 25 percent of the cardiac output for filtration purposes.