Khaleel Alyahya Monday May 4, 2009

Urinary System  Kidney  Ureters  Urinary Bladder  Urethra

Functions  Maintain the purity & constancy of internal fluids.  Regulate the blood volume.  Produce rennin (enzyme) that help to regulate blood pressure.  Erythropoietin (hormone) stimulate RBC production.  Convert vitamin D to its active form.  Manufacture urine.

Locations * Kidneys lie against the dorsal body wall in superior lumbar region * Extends from T12 to L3 vertebra * Receive protection from lower rib cage

Structures * Right kidney is slightly lower than the left. * Medial indentation is called the hilus. * Ureters, renal blood vessels & nerves enter or exit the kidney from the hilus * At the top of each kidney is an adrenal gland * A fibrous transparent renal capsule encloses each kidney followed by adipose capsule *Retroperitoneal

Structure of the Kidneys Kidney is divided into: Renal Cortex (outer region) Renal Medulla (inner region)

In the renal medulla pyramidal shaped medullary pyramids. Separated from cortex by renal columns. Calyces are the cup-shaped area on the tip of the pyramids The calyces collect the urine & continue as renal pelvis. Renal Medullla Structure of the Kidneys

Blood Supply of the Kidney  Renal arteries branchs  Renal artery  Segmental artery  Interlobar artery  Arcuate artery  Interlobular artery  Afferent arterioles  Renal venules follow similar opposing pattern ending with renal veins

Blood Supply of the Kidney

Nephron & Urine Formation The nephron consists of a renal corpuscle and renal tubule  The renal corpuscle is composed of  Bowman’s capsule and the glomerulus  The renal tubule consists of  Proximal convoluted tubule (PCT)  Loop of Henle  Distal convoluted tubule (DCT)  Nephron empties tubular fluid into collecting system  Collecting ducts and papillary ducts

Nephron & Urine Formation

The Ureters  Pair of muscular tubes  Extend from renal pelvis to the bladder * 25 to 30cm tubes start from the hilus of the kidney to the bladder * Carry urine from kidney to the bladder * Starts from hilus of the kidney * Enters in the posterior aspect of bladder * Runs behind the peritoneum

Urinary Bladder * Is a collapsible muscular sac that stores urine. * Located in the pelvis just posterior to the pubic symphysis * Internally a smooth triangular region in the base out lined by 3 openings (TRIGONE) * In males prostate gland surrounds the neck of the bladder * The bladder wall contains 3 layers of smooth muscle collectively called as DETRUSOR MUSCLE * The walls are thick & folded * Full bladder becomes a part of abdominal cavity * Moderately full bladder holds 500ml of urine but it can hold 1000ml

Urinary Bladder (male)

Urinary Bladder (female)

The Urethra * The urethra is a thin walled tube that carries urine by peristalsis from bladder to outside of body. * At bladder-urethra junction thickening of smooth muscle forms * INTERNAL URETHRAL SPHINCTER (involuntary) * EXTERNAL URETHRAL SPHINCTER is formed by skeletal muscle(voluntary)

Questions?