Excretory System Excretion – removal of metabolic waste

Urinary system made-up of the kidneys, ureters, bladder, and urethra kidneys filter waste from blood; collected as urine flows through ureters to the bladder stored then leaves through urethra

Kidney Structure 3 regions; Renal medulla - inner Renal cortex – outer part (contains nephrons) Renal pelvis - funnel shaped structure in the center of the kidney.

2 blood vessels enter and leave each kidney –renal artery enters –renal vein exists

Functional Unit of the Kidneys nephrons –approx 1 million per kid 3 functions: –filtration of water and solutes from the blood –reabsorption of water and molecules back into the blood –secretion of waste products from surrounding capillaries

Filtration Blood enters a nephron into the glomerulus The glomerulus is encased by the Bowman’s capsule –fluid from the blood is filtered –the filtrate contains water, urea, glucose, salts, amino acids, and vitamins

-urea - nitrogenous product made by the liver brought to liver as ammonia, converted to less harmful substance (urea) and enters the blood stream

Reabsorption Material removed from blood at Bowman’s cap makes it way back into the blood happens along nephron’s tubular parts Secretion waste and toxic material secreted from blood

purified blood returned to circulatory sys through renal vein

Nephron

The Kidneys ensure that the composition of our Blood remains Constant Concentration of water in blood –Drink too much liquid, and the Kidneys will decrease the rate of reabsorption, excess water is excreted. Level of salt in blood –Eat Salty Foods and the Kidneys will respond by returning less salt to the Blood by reabsorption. Excess is excreted

water reabsorption is controlled by the antidiuretic hormone (ADH) ADH is released from the pituitary gland in the brain

Kidney Stones excess wastes crystallize