Digestion - Lesson 3

Question 1

In which digestive organ does absorption take place?

Answer 1

Small Intestine

Question 2

Where does absorption take place in the Small Intestine?

Answer 2

occurs in the second (jejunum) and the third (ileum) parts of the small intestine.

Question 3

What increases the surface area in the small intestine?

Answer 3

The tiny folds called villi

Question 4

What are villi?

Answer 4

Tiny folds inside the small intestine

They greatly increase the absorptive surface area of the small intestine

Made from endothelial tissue

If you zoom in, you would see that the villi are covered in tiny projections called microvilli

Question 5

What is the role of the villi?

Answer 5

To absorb the nutrients.

Glucose, amino acids, and vitmains/minerals diffuse directly into the capillaries inside the villi.

Fatty acids and glycerol DO NOT diffuse directly into the capillaries -> it could lead to clogs

Question 6

What happens to the Fatty acids and glycerol during absorption?

Answer 6

They diffuse into the Lacteal - separate channels which are connected to the lymphatic system.

Question 7

What happens if the amino acids and glucose can’t diffuse into the capillaries because it would be against a concentration gradient?

Answer 7

Active transport occurs (uses ATP)

Carrier proteins in the villi move the amino acids and the glucose against the concentration gradient. They move from low concentration to high concentration

Question 8

What is the function of the liver?

Answer 8

There are 6 major functions

1. produce bile which is stored in the gallbladder
2. Destroy old red blood cells
3. Store glucose as glycogen
4. Detoxify blood by removing and metabolizing poisonous substances like alcohol
5. Produce blood proteins (like clotting proteins)
6. Produce urea

Question 9

How does the liver produce urea?

Answer 9

the liver deaminates amino acids (removes the amine group), producing toxic NH₃ (ammonia). The liver then converts NH₃ to urea which is non-toxic

** Deaminated amino acids can be used in cellular respiration to make ATP **

Question 10

What is the function of the Large Intestine?

Answer 10

The location of bacterial digestion (E. Coli)

Ferments carbohydrates, breakdown undigested material to produce vitamins and amino acids

Absorbs most of the water

Concentrates wastes for elimination/defecation