Excretory System

When things burn…

Excretion

• Waste materials from oxidation are removed• A kind of excretion is carbon dioxide being

expelled through the lungs.

Excretion

• Liver forms urea (caused by breakdown of proteins)

• Skin excretes water and salts

Main Excretory Organs: Kidneys

Parts of the Kidney

• Cortex – outermost region• Medulla – comprised of pyramids, inner 2/3• Pelvis- saclike cavity where urine is secreted• nephrons – tiny filters that control blood

composition• Bowman’s capsule – cup-shaped that forms one

of the tubule surrounding the glomerulus• glomerulus- mass of capillaries found in the

Bowman’s capsule

Urine formation

• Filtration• Reabsorption

Nephron

Functions of the parts of the kidney

• Renal corpuscle – unit of the nephron, glomerulus and Bowman’s capsule

• Proximal convoluted tubule- leads to the loop of Henle, regulates pH

• Loop of Henle – concentrates urine

Functions of the parts of the kidney

• Distal convoluted tubule- leads to the collecting duct system, regulates pH

• Collecting duct- final site for reabsorption

Diuretics

• Inhibit the nephron’s retention ability• Increases rate of urination