The small intestine, large intestine and Rectum

Question 1

Where does most chemical digestion of food molecules and absorption of nutrients occur?

Answer 1

Most chemical digestion of food molecules and absorption of nutrients occur in the small intestine.

Question 2

What are the three regions of the small intestine?

Answer 2

The three regions of the small intestine are the duodenum, the jejunum, and the ileum.

Question 3

How long is the duodenum and how is it connected to the stomach?

Answer 3

The duodenum is about a foot long and is connected to the stomach.

Question 4

What is the length of the jejunum?

Answer 4

The jejunum is approximately eight feet long.

Question 5

Which region of the small intestine is the longest and how long is it?

Answer 5

The ileum is the longest region of the small intestine, measuring about 11 feet in length.

Question 6

Why does the small intestine have a bristly texture inside?

Answer 6

The small intestine has a bristly texture inside because it is lined with rings of mucosa, which increases its surface area for nutrient absorption.

Question 7

What is the function of circular folds in the small intestine?

Answer 7

Circular folds in the small intestine increase its surface area for nutrient absorption

Question 8

What is the role of mucosa in the small intestine?

Answer 8

Mucosa in the small intestine produces mucus, which helps protect and lubricate the intestinal lining.

Question 9

Why does the small intestine have a bristly texture inside?

Answer 9

The small intestine has a bristly texture inside due to rings of mucosa called circular folds, which increase its surface area for nutrient absorption.

Question 10

What is the purpose of circular folds in the small intestine?

Answer 10

Circular folds increase the surface area of the small intestine, allowing for more efficient absorption of nutrients.

Question 11

What role does mucosa play in the small intestine?

Answer 11

Mucosa in the small intestine produces mucus, which helps protect the intestinal lining and facilitates the movement of food along the digestive tract.

Question 12

What is the role of the submucosa in the small intestine?

Answer 12

The submucosa attaches the mucosa to the muscular tissue of the small intestine, providing structural support.

Question 14

What are the two muscular layers that form the muscular tissue of the small intestine?

Answer 14

The circular muscularis and the longitudinal muscularis are the two muscular layers in the small intestine.

Question 15

What is the function of the serosa in the small intestine?

Answer 15

The serosa is a membranous tissue that protects the inner parts of the small intestine.

Question 16

What are intestinal villi?

Answer 16

Intestinal villi are tiny projections of cells that make up the circular folds in the lining of the small intestine.

Question 17

What are microvilli?

Answer 17

Microvilli are extensions on the membranes of cells within the intestinal villi. They further increase the surface area of each cell, aiding in nutrient absorption.

Question 18

how do intestinal villi and microvilli contribute to the function of the small intestine?

Answer 18

Intestinal villi and microvilli significantly increase the surface area of the small intestine, facilitating the absorption of nutrients from digested food.

Question 19

Where are intestinal glands located?

Answer 19

Intestinal glands are located between the villi in the lining of the small intestine.

Question 20

What is the function of intestinal glands?

Answer 20

Intestinal glands secrete digestive enzymes that further break down food molecules, allowing their nutrients to be absorbed by the body’s cells.

Question 21

What role do the liver and pancreas play in digestion?

Answer 21

The liver produces bile, which is stored in the gallbladder and released into the small intestine to aid in the digestion and absorption of fats. The pancreas secretes digestive enzymes into the small intestine to further break down carbohydrates, proteins, and fats.

Question 22

What structures in the villi absorb nutrients?

Answer 22

Capillaries and lacteals (lymph vessels) in the villi absorb nutrients from the digested food.

Question 23

Where do the absorbed nutrients go after being absorbed by the villi?

Answer 23

The absorbed nutrients are transported to the liver for processing.

Question 24

What role do capillaries play in the small intestine?

Answer 24

Capillaries in the villi of the small intestine absorb nutrients, deliver oxygen, and remove carbon dioxide to maintain the proper functioning of the intestinal cells.

Question 25

What are the two types of muscle contractions involved in moving chyme through the small intestine?

Answer 25

Peristaltic contractions and contractions of smooth muscles

Question 26

How do peristaltic contractions contribute to the movement of chyme in the small intestine?

Answer 26

Peristaltic contractions propel chyme slowly towards the large intestine by rhythmic contracting and relaxing of muscles.

Question 27

What is the function of the ileocecal sphincter?

Answer 27

The ileocecal sphincter regulates the passage of chyme from the small intestine to the large intestine.

Question 28

What are the four regions of the large intestine?

Answer 28

The ascending colon, transverse colon, descending colon, and sigmoid colon.

Question 29

What is the major function of the large intestine?

Answer 29

The major function of the large intestine is to remove most of the water from the chyme AND PUTTING IT BACK INTO BLOOD and to form feces

Question 30

Why can diarrhea be dangerous, especially in children?

Answer 30

Diarrhea can be dangerous, especially in children, because if water isn’t absorbed from the large intestine, the cells of the body can become dehydrated.

Question 31

What is the connection between the small intestine and the large intestine?

Answer 31

The connection between the small intestine and the large intestine is through the ileocecal sphincter.

Question 32

What are the four parts of the large intestine shown in the graphic?

Answer 32

The four parts of the large intestine shown in the graphic are the ascending colon, transverse colon, descending colon, and sigmoid colon.

Question 33

What role does bacteria in the large intestine play in digestion?

Answer 33

Bacteria in the large intestine ferment chyme, producing vitamins such as vitamin K and some B vitamins like biotin and folic acid.

Question 34

What nutrients are produced by bacteria in the large intestine?

Answer 34

Bacteria in the large intestine produce vitamin K and two of the B vitamins: biotin and folic acid.

Question 35

What are the two sphincters located at the end of the rectum?

Answer 35

The two sphincters located at the end of the rectum are the internal anal sphincter and the external anal sphincter.

Question 36

What type of muscle is the internal anal sphincter made of?

Answer 36

The internal anal sphincter is made of smooth muscle, which cannot be consciously controlled.

Question 37

What type of muscle is the external anal sphincter made of?

Answer 37

The external anal sphincter is made of skeletal muscle, allowing for conscious control.

Question 38

What triggers the defecation reflex?

Answer 38

The defecation reflex, or the urge to have a bowel movement, is triggered when enough feces are in the rectum.

Question 39

What happens when the internal anal sphincter opens during the defecation reflex?

Answer 39

The opening of the internal anal sphincter creates the urge to have a bowel movement.

Question 40

What controls the opening of the external anal sphincter during defecation?

Answer 40

The external anal sphincter can be voluntarily controlled by contracting the muscles that control it.

Question 41

The salivary glands secrete the _______. This enzyme breaks the bonds between components of ____. After the food is moistened in the mouth, it is called ———-

Answer 41

enzyme amylase
cARBOHYDRATE
a bolus.

Question 42

When you swallow, the ______ rises and closes off the nasal cavity, and the_____ travels through the______. The _____ seals off the ______, allowing the bolus to travel down the ______, after passing through the ________.

Answer 42

soft palate
bolus
pharynx
epiglottis
trachea
esophagus
upper esophageal sphincter.

Question 43

To enter the ______ of the stomach, the_______must pass through the______. Once in the stomach, the bolus is mixed with _____, a mixture of acids and enzymes, turning it into a semi-liquid substance called___.

Answer 43

cardiac region
bolus
lower esophageal sphincter
gastric juice
chyme

Question 44

____passes through the ____ into the small intestine, where nutrients are digested further and absorbed into the blood. To get into the large intestine, ____passes through the _____. Once in the large intestine, feces are formed.

Answer 44

Chyme
pyloric sphincter
chyme
ileocecal sphincter

Question 45

The feces leave the body through the____ and out the___. The_____, made up of smooth muscle, must relax, and the_____, made up of skeletal muscle, must contract for _____ to occur.

Answer 45

feces
rectum
anus
internal anal sphincter
external anal sphincter
defecation