5.2 Excretion as Homeostatic Control Flashcards
What is excretion?
Excretion is the removal of metabolic waste from the body.
Define metabolic waste.
Substances that are produced in excess as a result of metabolic processes in the cells.
What is egestion?
Egestion is the process of removing undigested food.
Why is it important to remove metabolic waste from the body?
Otherwise it will become toxic.
What are the 3 types of metabolic waste?
- carbon dioxide
- nitrogenous waste
- bile pigments
What are the 3 types of nitrogenous waste?
- ammonia
- urea
- uric acid
How is ammonia produced?
The deamination of excess amino acids.
What are liver cells called?
Hepatocytes
What is the function of the hepatic artery?
To transport oxygenated blood from the aorta to the liver. Hepatocytes are very active so they need a lot oxygen for respiration.
What is the function of the hepatic vein?
For deoxygenated blood to leave the liver and return to the vena cava and regular circulatory system.
What is the function of the hepatic portal vein?
To transport deoxygenated blood from the digestive system to the liver.
Why does deoxygenated blood from the digestive system go to the liver?
The blood is rich in the products of digestion which includes toxic substances absorbed from the intestines. The liver will make sure the substances don’t circulate in excess.
How can you distinguish the hepatic artery from the hepatic veins?
The hepatic artery is thinner than the hepatic vein and hepatic portal vein.
What is the function of the bile duct?
To carry bile from the liver to the gall bladder where it is stored until use.
What is the function of bile?
To help the digestion of lipids in the small intestine.
What is the liver divided into?
4 Lobes
What are lobes divided into?
Cylindrical lobules.
What are the 3 main functions of the liver?
- storage of glycogen
- detoxification of alcohol
- formation of urea