Excretion as an example of homeostatic control

5.1.2 in spec yellow mean check ppt

what is excretion

the removal of metabolic waste products of metabolism from the body

importance of removing metabolic wastes from the body

many of the chemical reactions of metabolism that take place in the cells of the body produce waste products that are toxic if allowed to build up

what substances are excreted from the human body

carbon dioxide excreted from the lungs. bile pigments excreted in the bile from the liver into the small intestine via the gallbladder and bile duct. urea excreted by the kidneys in urine.

how do bile pigments form

the breakdown of haemoglobin from old red blood cells in the liver

how is urea formed

the breakdown of excess amino acids by the liver. also known as nitrogenous waste. urea can also be described as an excess of amino acids

importance of excretion in maintaining metabolism and homeostasis

excess carbon dioxide can cause respiratory acidosis and amino acids contains almost as much energy as carbohydrates so the amino group is removed and ammonia is formed (ammonia is toxic)