Human Nutrition (Villi) Flashcards
What are contained in the lining of the duodenum and ileum?
Villi
How is food absorbed by villi?
By diffusion
What are the adaptations of the villi for absorption?
4
Large numbers
Large numbers of microvilli
Their walls are only one cell thick
They have a rich blood supply
As villi are numerous and their microvilli are also numerous, how does this aid absorption?
As they increase the surface area
What do the capillaries in each villus absorb?
Water and soluble nutrients
What soluble nutrients are absorbed by the capillaries?
4
Glucose
Amino acids
Vitamins
Minerals
Where do the capillaries in the villi carry nutrients to?
The hepatic vein
Where are the soluble nutrients taken by the hepatic vein?
To the liver
What does the liver do to nutrients?
It stores some and releases others for use throughout the body
What cannot be stores in the liver?
Excess amino acids
Why can excess amino acids not be stored by the liver?
As they become toxic
What is deamination?
The breaking down of excess amino acids by the liver to form urea
What is the breaking down of excess amino acids by the liver to form urea called?
Deamination
How does urea and other waste leave the liver?
Through the hepatic vein and eventually pass through the kidneys
What does urea form in the kidneys?
It becomes a part of urine which is then excreted
