Excretion PDF

Excretory System 2 Excretory System 3 Excretory System Metabolic Waste Substances left over from metabolic processes which cannot be used by the organism (they are surplus or are toxic) so they must be removed. Metabolic Process: Chemical reactions that occur...

Excretory System 2 Excretory System 3 Excretory System Metabolic Waste Substances left over from metabolic processes which cannot be used by the organism (they are surplus or are toxic) so they must be removed. Metabolic Process: Chemical reactions that occur within living cells. 4 Major Metabolic Wastes Carbon dioxide aerobic cellular respiration Water aerobic cellular respiration Mineral salts chemical reactions occurring in the cell (metabolism), sodium chloride, sodium sulfate Nitrogenous wastes breakdown of amino acids, ie. ammonia, urea, uric acid Heat exothermic chemical reactions release heat which must be released to maintain a constant temperature 5 Excretion Process by which organisms remove metabolic wastes and excess substances from the cells. Every cell in the body produces metabolic wastes which includes excess water and salts, carbon dioxide, and urea. Helps maintain homeostasis by removing wastes. 6 Organs of Excretion Skin ▹ and associated glands Lungs Kidneys ▹ part of urinary system ▹ MAJOR excretory organs Liver 7 Skin Some of skinʼs functions include: ▹ Protection from pathogens ▸ first line of defense of immune system ▹ Protection against water loss ▹ Temperature regulation 8 Lungs Remove carbon dioxide and water vapour 9 Liver The liver is the largest single internal organ in the body. The liver has three roles: ▹ Detoxification of blood ▹ Excretion of bile ▹ Formation of urea  10 Liver: Detoxification of Blood 11 Liver: Detoxification of Blood Long term abuse of poisons (ie. alcohol) may cause cirrhosis of the liver. Cirrhosis occurs when liver tissues overgrow and restrict the blood flow to the organ. 12 13 Liver: Excretion of Bile Bile ▹ Made by liver cells to neutralize stomach acids and emulsify fats in the small intestine. ▹ Consists of cholesterol, bilirubin (partially broken down hemoglobin from worn out red blood cells), and bile salts (mineral salts). ▹ Stored in the gallbladder and released to the small intestine. 14 Liver: Excretion of Bile ▹ Most of the bile salts are reabsorbed into the blood at the end of the small intestine to be filtered out and reused by the liver. ▹ The rest of the bile passes out with the feces. ▹ If the liver is failing, the bile is not excreted properly, and bilirubin (an element in bile) is reabsorbed into the blood. 15 16 Liver: Formation of Urea Proteins break down into amino acids. The livier will break down amino acids and convert the amino group into ammonia (a very poisonous substance). The liver will then convert ammonia into a less toxic form: urea Urea will be released into the bloodstream where it will be filtered out by the kidneys and removed via the urinary system.  Review + Preparation for 17 Urinary System… https://www.youtube.com/watch?v=WtrYotjYvtU