Urinary System

I. Functions of the Urinary System

A. Filtaration: Filters the blood, blood goes in and pee comes out

1. Helps maintain water balance

2. Helps maintain ion balance

3. Helps maintain acid-base balance

B. Excretion: Removal of metabolic waste

• metabolic waste- waste produced as a byproduct of metabolism

II. Organs of the Urinary System

A. Renal Artery and Renal Vein- Transports blood to and away from the kidney

B. Kidney- Filter blood, return useful materials, and convert wastes into urine

1. Renal cortex- Outer region of the kidney

2. Renal medulla- Middle region of the kidney

3. Renal Pelvis- Inner region of the kidney

C. Ureters- transport urine from the kidney to the bladder

D. Urinary Bladder- stores urine

E. Urethra- transport urine out of the body

1. prostate enlargement- constricts the urethra

2. Urinary tract infection (uti)- urethra is much shorter, bacteria from fecal matter can enter urethra

III. Producing urine

A. Nephrons- Kidneys functional unit

1. Glomerules- cluster of capillaries leading to the tubule

2. Tubules

   a. Bowman’s capsule- wraps around the glomerules

   b.Proximal convoluted tubule

   c. Loop of Henle

   d. Distal convoluted tubule

   e. collecting duct

3. capillaries- material exchange

B. Processes

1. Filtration- force of heartbeat forces plasma from glomerulus into tubule

   a. Bowmans capsule keeps cells and platlets in the bloodstream

2. Reabsorption- useful materials are transported from the tubule back into the blood

3. Secretion- waste materials are transported from the blood into the tubule

4. Excretion- removal of urine from the body

IV. Problems with Kidney Functions

A. Kidney stones- substances in the urine crystalize and can block the flow of urine as it moves

B. Kidney failure

1. Dialysis- machine filters blood for kidneys

2. Kidney Transplant- a new kidney is attached