lec11

The Urinary System By Dr.Israa H.Mohsen
Main Functions of Urinary System
?Kidneys filter blood to keep it pure
?Toxins
?Metabolic wastes
?Excess water
?Excess ions
?Dispose of nitrogenous wastes from blood
?Urea
?Uric acid
?Creatinine
?Regulate the balance of water and electrolytes, acids and bases
Kidneys are retroperitoneal organs (see next slide)
?Superior lumbar region of posterior abdominal wall
?Lateral surface is convex
?Medial surface is concave
?Hilus* is cleft: vessels, ureters and nerves enter and leave
?Adrenal glands* lie superior to each kidney
(the yellow blob in pic)
Kidney has two regions
The urinary system consists of two kidneys, two ureters, the urinary bladder, and the urethra. The major functions of the urinary system are removes waste products from the circulatory system, regulate blood pH, ion balance, and fluid balance and assist in regulating blood pressure.
The kidney structure
The kidneys are bean-shaped organs, each about the size of a tightly clenched fist. They lie on the posterior abdominal wall behind the peritoneum to either side of the vertebral column. A connective tissue renal capsule surrounds each kidney.
On the medial side of each kidney is the hilum, where the renal artery and nerves enter and where the renal vein and ureter exit the kidney. The hilum opens into a cavity called the renal sinus.
The kidney is divided into an outer cortex and an inner medulla, which surrounds the renal sinus. The bases of several cone-shaped renal pyramids are located at the boundary between the cortex and the medulla, and the tips of the pyramids project to the center of the kidney. A funnel-shaped structure called a calyx surround tip of each pyramid. The calyces from the entire pyramids join together to form a larger funnel called renal pelvis, which is located in the renal sinus. The renal pelvis then narrows to form a small tube, the ureter, which exits the kidney and connects to the urinary bladder. Urine passes from the tips of the pyramids into the calyces. From the calyces, urine collects in the renal pelvis and exits the kidney through the ureter.


?Cortex: outer
?Columns of cortex divide medulla into “pyramids”
?Medulla: inner
?Darker, cone-shaped medullary or renal pyramids
?Parallel bundles of urine-collecting tubules