Body Systems - 3.4 Waste Disposal Flashcards
What is defecation?
The process of getting rid of solid waste (faeces) from your body.
What is excretion?
Getting rid of waste your body has produced. It’s the function of the excretory system (lungs, skin, liver and kidneys).
How are the lungs apart of the excretory system?
The lungs breathe out carbon dioxide and water (produced by respiration) as waste products.
What is the end product of protein digestion?
Amino acids. They are used by the body to make proteins and for growth/repairs
(note: They can’t be stored and if you have more needed, it’ll be excreted).
What substance is made when the liver breaks down amino acids?
Urea.
What may enter the body from the digestive tract?
Poisonous substances, which are carried to the liver, where they’re broken down into harmless substances, which return to the blood.
What breaks down old red blood cells?
The liver
What do chemical reactions taking place in your body produce?
Heat (as a by-product). Some of this heat is needed to keep your body temperature at 37°C.
Where does unwanted haemoglobin get added to?
Bile and passed with it to the intestines.
What happens if you don’t get rid of the excess heat?
Your temperature will rise. You’ll lose much of your excess heat through your skin by sweating, that has small traces of urea.
What are kidneys?
They are 2 bean-shaped organs that act as filters that process about 50L of blood every hour.
What do the kidneys excrete?
Urea, which is a waste product when proteins are broken down.
What do the kidneys control?
They control the level of water in the body and the salt levels in the blood (excess salt is removed in urine).
What is urine?
The waste material that has been filtered out of the blood by the kidneys.
How does urine pass from the kidneys down to the bladder?
Down a narrow tube (ureters).
