Exam 3 Digestive System

Question 1

Know the functions of the accessory digestive organs

Answer 1

teeth: mastication
tongue: assist in swallowing
gallbladder: store bile
salivary glands: make saliva
liver: make and secrete bile
pancreas: make enzymes

Question 2

Define segmentation. Where does it occur

Answer 2

The small intestine carries on mixing movements that include:
*Segmentation – ring-like contractions that can move chyme back and forth (intestines)

Question 3

Define peristalsis. Where does it occur ?

Answer 3

The small intestine carries on mixing movements that include:
* Peristalsis – pushing movements that propel chyme ( GI tract)

Question 4

Know where the following nutrients are broken down: carbohydrates, proteins

Answer 4

Carbohydrates: pancreas and mouth
proteins: small intestine

Question 5

Know where the following nutrients are broken down: lipids, nucleic acids

Answer 5

Lipids: oral cavity and lingual lipases
Nucleic acids: small intestine

Question 6

What are the 3 digestive enzymes

Answer 6

salivary amylase, pepsin, gastric lipase

Question 7

Describe the digestive enzyme: pepsin

Answer 7

• pepsin: serves to digest proteins found in ingested food; Is a protein splitting enzyme
  Break down proteins in consumed food

Question 8

Describe the digestive enzyme: salivary amylase

Answer 8

• Salivary amylase: Serous cells produce a watery fluid with a digestive enzyme called salivary amylase, which splits starch into disaccharides

Question 9

Describe the digestive enzymes: gastric lipase

Answer 9

gastric lipase: From chief cells, Fat splitting, Weak due to low pH

Question 10

What are the functions of the following secretions: pepsinogen, intrinsic factor

Answer 10

pepsinogen: breaks down proteins in food during digestion.

intrinsic factor: transportation and absorption of the vital micronutrient vitamin B12

Question 11

What are the functions of the following secretions: HCl, mucous

Answer 11

HCl: kills food-derived bacteria, facilitates food digestion
mucous: moistens, lubricates, and protects passages of the digestive and respiratory tracts

Question 12

Describe the steps involved in swallowing.

Answer 12

1) Voluntary stage: saliva is mixed with chewed
food, forming a bolus
2) Swallowing begins and the swallowing reflex is
triggered
3) Peristalsis transports bolus in the esophagus to the stomach

Question 13

The gastric cells secrete which substances? (chief and parietal)

Answer 13

Chief cells: pepsinogen, gastric lipase
parietal cells: hydrochloric acid, intrinsic factor

Question 14

Which hormones affect gastric secretion and how? (Somatostatin, CCK, gastrin)

Answer 14

Somatostatin: inhibits acid secretion
CCK (Cholecystokinin): decreases gastric motility
gastrin: increases gastric juice secretion

Question 15

Describe the 3 phases of gastric secretion

Answer 15

*Cephalic Phase: Gastric juice is secreted in response to stimulus such as the smell, or taste of food.
*Gastric Phase: food in stomach chemicallyy and mechanically stimulates release of gatrin which then stimulates secretion of gastric juice.
*Intestinal Phase: inhibits gastric juice secretion

Question 16

What are the 4 substances the stomach can absorb?

Answer 16

water, certain salts, certain lipid-soluble drugs and alcohol

Question 17

Define bolus

Answer 17

bolus: a small rounded mass of a substance, especially of chewed food at the moment of swallowing.

Question 18

Define chyme

Answer 18

Chyme: the pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food.

Question 19

Describe the functions of the pancreatic enzymes (juice): lipase, amylase, trypsin, chymotrypsin,

Answer 19

• Lipase – breaks down fats into fatty acids and glycerol
  *amylase – splits glycogen into disaccharides
  *Trypsin – digests proteins
  *Chymotrypsin – digest proteins

Question 20

Describe the functions of the pancreatic enzymes (juice):
carboxypeptidase, nucleases, bicarbonate

Answer 20

• Carboxypeptidase – digests proteins
  *Nucleases – digest nucleic acids
• Bicarbonate ions – make pancreatic juice alkaline

Question 21

Describe the functions of the liver. (there are many, probably should know them…..

Answer 21

• Produces glycogen from glucose
• Breaks down glycogen into glucose
• Oxidizes fatty acids
• Forms urea
• Synthesizes plasma proteins
• Acts as blood reservoir
• Stores glycogen, iron, and vitamins A, D, and B12

Question 22

Describe the function of the hepatic portal system

Answer 22

returns blood from the digestive tract and spleen to the liver (where raw nutrients in blood are processed before the blood returns to the heart).

Question 23

Describe the composition of bile and know its functions

Answer 23

Bile is a yellowish-green liquid that hepatic cells continuously secrete
Composition: water, bile salts, bile pigments, cholesterol and electrolytes.

Functions: helps with digestion. It breaks down fats into fatty acids
- Absorption of fat and fat-soluble vitamins.

Question 24

What does each enzyme breakdown?( pancreatic juice);
chymotrypsin and nucleases

Answer 24

• Chymotrypsin – digest proteins – released as
  inactive…activated by trypsin
• Nucleases – digest nucleic acids

Question 25

What does each enzyme breakdown? ( pancreatic juice);
Pancreatic amylase, pancreatic lipase, trypsin

Answer 25

*Pancreatic amylase – splits glycogen into disaccharides
* Pancreatic lipase – breaks down triglycerides
* Trypsin – digests proteins – released as inactive trypsinogen, which is activated by enterokinase

Question 26

What is the composition of pancreatic juice?

Answer 26

Pancreatic amylase, pancreatic lipase, trypsin, Chymotrypsin, nucleases.

Question 27

What are the functions of the small intestinal secretions: peptidase, lipase

Answer 27

*Peptidase – breaks down peptides into amino acids
*Lipase – breaks down fats into fatty acids and glycerol

Question 28

What are the functions of the small intestinal secretions: peptidase, sucrase, maltase, lactase, and lipase

Answer 28

*Peptidase – breaks down peptides into amino acids
*Sucrase, maltase, lactase – break down disaccharides into monosaccharides
*Lipase – breaks down fats into fatty acids and glycerol

Question 29

Understand the functions of the small intestinal hormones: enterokinase, somatostatin

Answer 29

• Enterokinase – converts trypsinogen to trypsin
  *Somatostatin – hormone that inhibits acid secretion by stomach

Question 30

Understand the functions of the small intestinal hormones: CCK,
and secretin

Answer 30

*Cholecystokinin – hormone that inhibits gastric glands, and stimulates the gallbladder to release bile
*Secretin – stimulates the pancreas to release bicarbonate ions in pancreatic juice

Question 31

What are the functions of the large intestine?

Answer 31

Absorbs water and electrolytes
• Secretes mucus
• Houses intestinal flora: Vitamin Bs, K
• Forms feces
• Carries out defecation