Urinary System Essay

20439 Words82 Pages
Samuel Lee Medical Terminology Secition 05 Susan Elizabeth RESEARCH PAPER ON THE URINARY SYSTEM The urinary system consists of the kidneys, ureters, urinary bladder and urethra. The paired kidneys are located retroperitoneally against the posterior body wall. They receive blood from the renal arteries, filter the blood and return it to the general circulation through the renal veins. Each kidney is surrounded by a tough fibrous capsule. Within the capsule, the kidney is divided into an outer cortex and an inner medulla. Each kidney is made up of about one million nephrons. A nephron is the basic filtering unit of the kidney. It is made up of blood vessels and tubules which radiate outward from the hilum of the kidney, the medial notch where the major blood vessels and ureters enter the kidney. Each renal artery enters its respective kidney at the renal hilus and divides into interlobar arteries. These arteries divide into smaller arcuate arteries and interlobular arteries. The smallest branches of the interlobular arteries are the afferent arterioles which carry blood into the glomerulus a knot of capillaries at the core of each nephron. The afferent arterioles are also lined with juxtaglomerular cells which help to control blood pressure.Each glomerulus is surrounded by a cup-shaped structure call Bowman's capsule. The blood pressure in the glomerulus is high enough that about 10% of the blood fluid volume is squeezed out and absorbed by the Bowman's capsule. The remaining blood is carried out of the glomerulus through the efferent arteriole. The fluid absorbed into Bowman's capsule passes through a number of tubules and, as it does so, some constituents are reabsorbed into the blood, while some waste products in the blood are forced into the fluid. In order, from Bowman's capsule, the tubules of the nephron are called the proximal convoluted tubule, the
Open Document