EXCRETORY SYSTEM

Excretion Removal of cellular waste products from an organism

Main Wastes Products Carbon Dioxide: From cell respiration Water: From most reactions Salts: Urea: (Nitrogenous Wastes) Mostly from using proteins

We Excrete 3 ways:

ACTUAL WASTES

Excretory wastes may be either toxic or nontoxic. When toxic wastes are produced they are normally released, as in animals, or sealed off and stored, as in plants. Nontoxic waste materials may either be retained, released, or recycled in other metabolic activities.

Major Human Excretory Organs Lungs - organs of gas exchange Excrete 1. CO 2 2. Water

Liver - 3 Major Functions 1. Makes Bile (Digestion) 2. Breaks apart Blood Cells (Circulatory) ***3. DETOXIFICATION – (Excretory) Changes toxic things into less toxic things

Urea Production Proteins  Amino Acids  NH 3 Liver takes NH 3  Urea Urea is less toxic than NH 3

 Cirrhosis – Liver disease Too many toxins…… Alcohol Drugs Diet Liver stops working

Jaundice – Too many toxins in blood Yellow Color in eyes and skin Leads to gout

Gout Too many toxins in blood for too long May have to amputate Web MD Gout

Urinary System – system to remove wastes from blood through urine

Kidneys - Major Function: 1. Filters wastes from blood and produces urine 2 bean shaped organs….need only one

Urine Includes: Water – 95% Urea – 4.5% Salt -.5%

Nephron – structure that make up kidneys Filters in kidneys Millions of them

Parts of nephron Bowman’s Capsule – Absorbs all materials from blood(Some good and bad) (The Sink) Capillaries –(surround tubule) Absorb good materials back into blood Glomerulus – Ball of capillaries – filter wastes from

Other Key Excretory Structures: Ureter: tube takes urine from kidneys to bladder (2 of them) Urinary bladder: sac that stores the urine Stretches (folded) Empty when about 60% full Urethra: tube carries urine from bladder to outside

Skin – largest ORGAN in the body! - main function is protection, but there are many others - Cool Body, Excrete Waste Two main layers Epidermis – dead outside layer Dermis – living inside layer

nerves Allow for detection of stimuli Several different types of nerves: Pressure Heat Cold Pain

Capillaries Carries nutrients to living cells and takes away wastes Some wastes and water are taken from capillaries and given to sweat gland to release

2 Chief SWEAT GLAND Functions: 1. Aid in temperature regulation of the body. ** HOMEOSTASIS** 2. Excretes urine like wastes. (Water – 98%, salt, and some urea – 2%)

** Perspiration is only incidentally excretory; its MAIN function is temperature regulation. ** Temperature regulation is an example of homeostasis. **

Sebaceous Gland Oil gland Prevents drying out of skin Keeps it water resistant

RECAP Excretion – Removal of cellular waste Lungs Liver Kidney Skin WHY DO WE NEED AN EXCRETORY SYSTEM????? SINGLE CELLED ORGANISM EXCRETE USING WHCH ORGANELLE????

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