Excretion Flashcards
What is excretion?
The removal of metabolic waste
What is egestion?
The elimination of faeces
Which substances need to be excreted?
CO2
Nitrogen containing compounds (urea)
Other compounds such as bile pigments
What are the main excretory organs?
Lungs - removal of CO2 & water vapour
Kidneys - removal of urea
Liver - production of bilirubin and urea
Skin - removal of salts, urea, water etc. via sweat
How does oxygenated blood travel to the liver?
Oxygenated blood from the heart travels to the liver via the aorta and hepatic artery
What does “hepatic” refer to?
The liver
How is blood removed from the liver?
Blood leaves the liver and returns to the heart via the hepatic vein which re-joins the vena cava
What is the role of the hepatic portal vein?
It carries the products of digestion to the liver, directly from the intestines
Where is bile produced and secreted?
It is produced and secreted in the liver
What does “renal” refer to?
The kidneys
Where is bile stored?
Bile is stored in the gall bladder
Where is bile released?
Bile is released by the bile duct into the small intestine where it then emulsifies fats
What are hepatocytes?
Liver cells
Features of hepatocytes
Large nuclei
Prominent Golgi apparatus
Lots of mitochondria
What are sinusoids?
The space surrounded by hepatocytes
Functions of the liver
Control blood glucose levels
Synthesis of bile, cholesterol
Breakdown of hormones
Destruction of red blood cells
What is the role of catalase?
Catalase converts hydrogen peroxide to oxygen and water
What is the role of Cytochrome p450?
Cytochrome p450 is a group of enzymes used to breakdown drugs
What is the role of alcohol dehydrogenase?
Alcohol dehydrogenase breaks down ethanol into ethanal.
Ethanal is then converted to ethanoate