Module 5 ; Excretion as an example of homeostasis Flashcards
What is excretion and what is it’s purpose?
Excretion is the removal of unwanted waste products.
All chemical reactions in the body make up metabolism which produces waste products, many are toxic, an accumulation could cause cell and tissue damage.
What is the difference between excretion and egestion?
Excretion is the removal of metabolic waste products from the body.
Egestion is the removal of faeces (undigested remains of food)
Which substances need to be excreted?
CO2 from respiration.
Nitrogen containing compounds like urea.
Other compounds like the bile pigment in faeces.
What are the 4 main excretory organs?
Skin (removal of salts, urea, water, uric acid and ammonia in sweat)
Liver (production of bilirubin and urine)
Kidneys (removal of urea)
Lungs (removal CO2 and water)
Draw the structure of the liver.
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What are the features of the liver?
It is the largest internal organ, made up of several lobes.
Damaged areas regenerate quickly.
There is a rich blood supply.
What vessels does oxygenated blood travel through to get from the heart to the liver?
Aorta and hepatic artery.
What vessel does deoxygenated blood leave the liver and travel back to the heart?
The hepatic vein, eventually connecting to the vena cava.
What does the hepatic portal vein do?
It carries the products of digestion directly from the intestines to the liver.
Where is bile secreted and stored?
It is produced and secreted by the liver and stored in the gall bladder.
Where does the bile duct release bile?
It releases bile into the small intestine to emulsify fats.
What are bile pigments?
They leave the body in faeces, example bilirubin
What are hepatocytes?
What is their structure?
They are liver cells.
They have large nuclei, prominent golgi apparatus and many mitochondria bc they are metabolically active.
Draw a hepatic lobule.
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