16 - Digestive System

Question 1

What are the 4 major functions of the Digestive System?

Answer 1

1. Ingestion of food
2. Digestion of food
3. Absorption of nutrients
4. Elimination of wastes

Question 2

The digestive tract consists of which areas?

Answer 2

Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and anus.

Question 3

Nearly all segments of the digestive tract consist of four layers, called tunics. There are …

Answer 3

1. The mucosa
2. The submucosa
3. The muscularis
4. The serosa

Question 4

One of the four tunics of the digestive system is the mucosa. What is its structure?

Answer 4

The mucosa consists of mucous epithelium, a loose connective tissue called the lamina propria, and a thin smooth muscle layer, the muscular mucosae.

Question 5

One of the four tunics of the digestive system is the submucosa. What is its structure?

Answer 5

The submucosa lies just outside the mucosa. It is a thick layer of loose connective tissue containing nerves, blood vessels, and small glands. An expensive network of nerve cell processes forms a plexus. Autonomic nerves innervate this plexus.

Question 6

One of the four tunics of the digestive system is the muscularis. What is its structure?

Answer 6

The muscular is the third layer of the digestive system. In most parts of the digestive tract it consists of an inner layer of circular smooth muscle, and an outer layer of longitudinal smooth muscle. Another nerve plexus, also innervated by autonomic nerves, lies between the two muscle layers.

Question 7

One of the four tunics of the digestive system is the serosa. What is its structure?

Answer 7

The serosa consists of the peritoneum, which is a smooth epithelial layer, and its underlying connective tissue. Regions of the digestive tract not covered by the peritoneum are covered by a connective tissue layer called the adventitia.

Question 8

What is the enteric nervous system?

Answer 8

Together, the nerve plexuses of the submucosa and the muscular compose the enteric nervous system. This nervous system, which is a division of the autonomic nervous system, is extremely important in controlling movement and secretion within the tract.

Question 9

The peritoneum is a membrane of what type?

Answer 9

It’s a serous membrane. This is probably also why the outer layer of the digestive system is called the serosa.

Question 10

Mention the fluids or enzymes in the mouth responsible for digestion.

Answer 10

1. Saliva
2. Salivary amylase
3. Lysozyme

Question 11

Mention the fluids or enzymes in the stomach responsible for digestion.

Answer 11

1. Hydrochloric acid
2. Pepsin
3. Mucus
4. Intrinsic factor

Question 12

Mention the fluids or enzymes in the small intestine and associated glands that are released by the liver.

Answer 12

1. Bile salts

Question 13

Mention the fluids or enzymes in the small intestine and associated glands that are released by the pancreas.

Answer 13

1. Bicarbonate ions
2. Trypsin, chymotrypsin, carboxypeptidase
3. Pancreatic amylase
4. Lipase
5. Nucleases

Question 14

Mention the fluids or enzymes in the small intestine and associated glands that are released by the duodenal glands and goblet cells.

Answer 14

Mucus

Question 15

Mention the fluids or enzymes in the small intestine and associated glands that are released by the small intestine

Answer 15

1. Peptidase
2. Sucrase
3. Lactase
4. Maltase

Question 16

What is the source and function of saliva?

Answer 16

Saliva is produced by the salary glands. It moistens and lubricates food, neutralises bacterial acids, flushes bacteria from the oral cavity.

Question 17

What is the source and function of salivary amylase?

Answer 17

Salivary amylase is produced by the salivary glands. It digests starch.

Question 18

What is the source and function of lysozyme?

Answer 18

Lysozyme is produced by the salivary glands. It has weak antibacterial action.

Question 19

What is the source and function of hydrochloric acid?

Answer 19

Hydrochloric acid is produced by the gastric glands. It kills bacteria and converts pepsinogen to pepsin.

Question 20

What is the source and function of pepsin?

Answer 20

Pepsin is produced by the gastric glands. It digests protein.

Question 21

What is the source and function of mucus in the stomach?

Answer 21

Mucus is produced by the mucous cells in the stomach. It protects stomach lining.

Question 22

What is the source and function of intrinsic factor?

Answer 22

Intrinsic factor is produced by the gastric glands. It binds to vitamin B12, and aids in its absorption.

Question 23

What is the source and function of bile salts?

Answer 23

Bile salts are produced by the liver. They help emulsify fat.

Question 24

What is the source and function of bicarbonate ions?

Answer 24

Bicarbonate ions are produced by the pancreas and help neutralise stomach acid.

Question 25

What is the source and function of trypsin, chymotrypsin and carboxypeptidase?

Answer 25

They are all produced by the pancreas, and help digest protein.

Question 26

What is the source and function of pancreatic (!) amylase?

Answer 26

Yes, it is produced by the pancreas. It helps digest starch.

Question 27

What is the source and function of Lipase.

Answer 27

Lipase is produced by the pancreas. It helps digest lipid.

Question 28

What is the source and function of nucleases?

Answer 28

Nucleases is produced by the pancreas, and helps digest nucleic acid (DNA or RNA)

Question 29

What is the source and function of mucus in the small intestine and associated glands?

Answer 29

Mucus is produced by the duodenal glands and goblet cells. It helps protect duodenum from stomach acid and digestive enzymes.

Question 30

What is the source and function of peptidases?

Answer 30

Peptidases are produced by the small intestine, and help digest polypeptide.

Question 31

What is the source and function of sucrase?

Answer 31

Sucrase is produced by the small intestine, and helps digest sucrose.

Question 32

What is the source and function of maltase?

Answer 32

Maltase is produced by the small intestine, and helps digest maltose.

Question 33

The small intestine is divided into the …

Answer 33

duodenum, jejunum and ileum.

Question 34

In what part of the small intestine does most of the absorption occur?

Answer 34

In the duodenum and jejunum.

Question 35

The liver receives blood from…

Answer 35

The hepatic artery and the hepatic portal vein.

Question 36

What are the two main functions of the liver?

Answer 36

1. The liver produces bile, which contains bile salts that emulsify fats, and excretory products.
2. The liver stores and processes nutrients, produces new molecules, and detoxifies molecules.

Question 37

What are the two main functions of the pancreas?

Answer 37

1. The pancreas produces HCO3- and digestive enzymes.
2. Acidic chyme stimulates the release of a watery bicarbonate solution that neutralises acidic chyme. Fatty acids and amino acids in the duodenum stimulate the release of pancreatic enzymes.

Question 38

What is chyme?

Answer 38

Chyme (/kaɪm/; from Greek χυμός khymos, “juice”[1][2]) is the semifluid mass of partly digested food that is expelled by the stomach into the duodenum and moves through the intestines during digestion.[3]

Question 39

What are the three main functions of the large intestine?

Answer 39

1. The functions of the large intestine are faces production and water absorption.

Question 40

What are the effects of waging on the digestive system?

Answer 40

1. The layers of the digestive tract thin, and the blood supply decreases.
2. Defences of the digestive tract decline, leaving it more sensitive to infection and the effects of toxic agents.
3. Tooth enamel becomes thinner, and the gingival recede, exposing dentin, which may become painful and affect eating habits.