Sec 32.3: Absorption of Nutrients

Question 1

What is absorption?

Answer 1

It is the process by which nutrients move out of the digestive organs into the circulatory (bloodstream) and lymphatic systems.

Question 2

Describe the lining of the small intestine and its function

Answer 2

The lining is rigid and folded, which increases the surface area and slows the passage of materials through the intestine, allowing for more time for absorption.

Question 3

What are villi?

Answer 3

They are small fingerlike projections that cover the folds of the small intestine lining and are covered with epithelial cells that absorb nutrients

Question 4

What are microvilli?

Answer 4

They are tiny projections on the epithelial cells of the villi that add even more surface area to absorb nutrients

Question 5

What are the 3 sections of the small intestine? How long is the entire small intestine?

Answer 5

Duodenum, jejunum, & ileum. 6 meters (20 ft) long

Question 6

What nutrients do villi in the duodenum absorb?

Answer 6

Simple sugars, amino acids, and minerals (calcium and iron). They diffuse into the circulatory system and are carried to the liver.

Question 7

What nutrients do villi in the jejunum absorb?

Answer 7

Glucose, some amino acids, vitamin C, most B vitamins, and some water. They diffuse into the circulatory system to be distributed to the rest of the body.

Question 8

What nutrients do villi in the ileum absorb?

Answer 8

Fat-soluble vitamins, vitamin B12, fatty acids, cholesterol, and some water. They diffuse into lymph and blood vessels and are distributed to the cell.

Question 9

What enters the liver after absorption in the small intestine? What is it used for?

Answer 9

Nutrient-rich blood. Enzymes use some to build more complex molecules needed by cells, and some are stored in liver tissues (such as excess glucose stored as glycogen)

Question 10

What is the large intestine otherwise known as? How long is it?

Answer 10

The colon, 1.5 meters long (5 ft)

Question 11

How much water does it absorb per day? Why?

Answer 11

It absorbs about 1 liter of water a day, and along with some salts, this helps to maintain fluid balance

Question 12

What is feces?

Answer 12

It is a solid mass of remaining undigested materials, partly composed of undigested fiber from plant foods, dead bacteria, and traces of undigested fat and protein.

Question 13

Where does feces get its brown color from?

Answer 13

From bile pigments from the liver

Question 14

What is the rectum?

Answer 14

It is a tube that connects the large intestine to the anus, and where feces is stored until excretion

Question 15

What is the anus?

Answer 15

Is where feces is eliminated through.

Question 16

What do some of the many types of bacteria in the large intestine do?

Answer 16

Some synthesize a few B vitamins and vitamin K (blood-clotting factor).
Others, such as Escherichia coli (E. coli), live harmlessly until some disturbance (illness) allows them to overgrow other bacteria

Question 17

What can an overgrowth of E. coli cause?

Answer 17

It can reduce water absorption and cause severe diarrhea.