Anatomy for Medical Coder- Urinary System

Urinary System for CPC Fresher

Urinary ( Excretory ) System

The urinary (excretory) system consists of two kidneys, two ureters, one urinary bladder, and one urethra. Its primary function is to filter blood, remove waste products, regulate water and electrolyte balance, and produce urine.

Important organ involve in circulatory sytem

1.Kidney:

The kidneys are bean-shaped, reddish-brown organs located on the posterior abdominal wall (retroperitoneal) between the T12 and L3 vertebrae.

On the medial (inner) border of each kidney is a depression called the hilum, through which the renal artery, renal vein, ureter, lymphatics, and nerves enter or leave the kidney. Just inside the hilum is the renal pelvis, a funnel-shaped structure that collects urine from the major and minor calyces before passing it into the ureter.

The kidney is surrounded by a fibrous renal capsule for protection. Internally, it has two regions:

• Renal Cortex: Outer region containing most of the glomeruli and the initial parts of the nephrons.

• Renal Medulla: Inner region composed of renal (medullary) pyramids, which drain urine into the calyces.

Each kidney contains millions of tiny filtering units called nephrons, which filter blood, reabsorb necessary substances, and secrete waste into the urine.

2.Ureter: The ureters are two long, muscular tubes that transport urine from the kidneys to the bladder. They use rhythmic contractions called peristalsis to move urine downwards.

3.Bladder: The bladder is a hollow, muscular organ that stores urine.​​​

4.Urethra:The urethra is the tube that carries urine from the bladder to the outside of the body during urination.

Process of Urine Formation:

1. Filtration:

   • Blood enters the kidneys through the renal arteries and is filtered in the glomerulus (a network of tiny capillaries) within the nephron. The filtrate that is produced contains water, electrolytes, glucose, urea, and other small molecules.

2. Reabsorption:

   • The filtrate moves through the renal tubules (proximal convoluted tubule, loop of Henle, distal convoluted tubule), where essential substances like glucose, amino acids, and most of the water are reabsorbed into the bloodstream.

3. Secretion:

   • Additional waste products and excess substances, like hydrogen ions and potassium, are actively secreted into the filtrate from the blood.

4. Excretion:

   • The remaining waste products, along with water, form urine, which flows into the renal pelvis, through the ureters, and is stored in the bladder until it is ready to be excreted from the body.