Anatomy and Function of the Human Urinary System
Function of the Urinary Tract
The function of the urinary tract is responsible for ridding the blood of waste products that accumulate in the bloodstream and eliminating the urine to the exterior. Urine is formed through the kidneys and the urinary tract (comprising two ureters, the bladder, and the urethra).
Gross Anatomy of the Kidney
The kidney is an organ pair (right and left) situated in the pits on both sides of the lumbar spine. In the upper pole of each kidney, adrenal glands are located; however, there is no functional relationship between them. All of this is wrapped in a layer of fat, or the renal adipose capsule, which is coated with a layer of connective tissue called Gerota's fascia.
Internal Structure: Cortex and Medulla
In the gross anatomy of the kidney, specifically in a longitudinal section, we macroscopically distinguish the cortex and medulla. The cortex or periphery area has a yellowish and granular appearance. The medullary inner zone is reddish and consists of two areas: cones with bases in the cortex and the vertex that ends in the renal papillae, called Malpighian pyramids. Between the pyramids are extensions of the cortex called the columns of Bertin.
Renal Papilla, Calyces, and Pelvis
Regarding the renal papilla and the difference between the calyces and renal pelvis: in the renal papillae, there are small bags or leaves where the calyces gather together to form the renal pelvis. This is continuous with the ureter. Urine is collected from the papillae by the calyces; from there, it passes from the pelvis to the ureter and then to the urinary bladder. The calyces and pelvis anatomically belong to the kidney and are also functional parts of the urinary tract.
Microscopic Anatomy of the Kidney
The microscopic anatomy of the kidney reveals that the functional unit structure of the kidney is the nephron, with about a million nephrons per kidney. Each nephron is made up of the kidney or Malpighian corpuscle, which has two parts: a ball of glomerular capillaries that acts as a branch of the renal arteries (a ball of capillaries formed from a branch of capillaries in the kidney arteries: the afferent arteriole and efferent arteriole). Efferent arterioles come together to form the renal veins and the peritubular capillary network. The Bowman's capsule is a double-walled sac surrounding the glomerulus; the space between the two leaves is the capsular space.
The Renal Tubular System
The tubular system is the continuation of the Bowman's capsule and consists of the proximal convoluted tubule and the loop of Henle (which is a portion