digestive system

Question 1

What is the main purpose of the digestive system?

Answer 1

To break down food into nutrients that can be absorbed and used by the body.

Question 2

What are the 4 stages of digestion?

Answer 2

• Ingestion
• Digestion (mechanical & chemical)
• Absorption
• Elimination

Question 3

What’s the difference between mechanical and chemical digestion?

Answer 3

• Mechanical = physical breakdown (e.g. chewing)
• Chemical = enzymatic breakdown into molecules

Question 4

What is peristalsis?

Answer 4

A series of wave-like muscle contractions that move food through the digestive tract.

Question 5

What organs make up the alimentary canal?

Answer 5

• Mouth
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Rectum
• Anus

Question 6

What accessory organs assist digestion?

Answer 6

• Salivary glands
• Liver
• Gallbladder
• Pancreas

Question 7

What is the epiglottis and why is it important?

Answer 7

A flap of cartilage that prevents food from entering the trachea during swallowing.

Question 8

What is the role of the mouth in digestion?

Answer 8

Begins mechanical digestion (chewing) and chemical digestion of carbohydrates via saliva.

Question 9

Which enzyme starts carbohydrate digestion in the mouth?

Answer 9

Salivary amylase.

Question 10

What is a bolus?

Answer 10

A soft, round mass of chewed food ready to be swallowed.

Question 11

What happens in the esophagus?

Answer 11

Food is moved from the mouth to the stomach via peristalsis. No digestion occurs here.

Question 12

What prevents food from entering the stomach too early or flowing back into the esophagus?

Answer 12

The lower esophageal (cardiac) sphincter.

Question 13

What are the three main functions of the stomach?

Answer 13

• Store food
• Mix and churn food
• Begin protein digestion

Question 14

What enzyme is responsible for protein digestion in the stomach?

Answer 14

Pepsin (activated from pepsinogen by HCl).

Question 15

What do parietal cells secrete and why?

Answer 15

• Hydrochloric acid (HCl)
• To kill microbes and activate pepsinogen

Question 16

What is chyme?

Answer 16

Semi-liquid food mixed with gastric juices leaving the stomach.

Question 17

What are the 3 sections of the small intestine?

Answer 17

• Duodenum
• Jejunum
• Ileum

Question 18

Where does most digestion and absorption occur?

Answer 18

In the small intestine, mainly the duodenum (digestion) and jejunum (absorption).

Question 19

What are villi and microvilli?

Answer 19

Tiny finger-like projections that increase the surface area for absorption in the small intestine.

Question 20

What enzymes are secreted in the small intestine?

Answer 20

• Enzymes from intestinal glands
• Pancreas (e.g. lipase, trypsin, amylase)

Question 21

What does the liver produce that helps digest fats?

Answer 21

Bile.

Question 22

What is the role of the gallbladder?

Answer 22

Stores and concentrates bile, releasing it into the small intestine.

Question 23

What is the role of bile?

Answer 23

Emulsifies fats, breaking them into smaller droplets for easier digestion by lipase.

Question 24

What does the pancreas secrete?

Answer 24

• Digestive enzymes (lipase, amylase, trypsin)
• Bicarbonate to neutralize stomach acid

Question 25

Where are carbohydrates, proteins, and fats absorbed?

Answer 25

In the small intestine (mostly the jejunum and ileum).

Question 26

How are nutrients transported into the blood?

Answer 26

Via diffusion or active transport through the villi into capillaries or lacteals.

Question 27

What nutrient enters lymph instead of blood?

Answer 27

Fats (as fatty acids and monoglycerides → absorbed into lacteals).

Question 28

What are the functions of the large intestine?

Answer 28

* Absorption of water and electrolytes * Formation and elimination of feces

Question 29

What is the main function of gut bacteria?

Answer 29

Fermentation of undigested food, production of vitamins (e.g., vitamin K).

Question 30

What is the difference between the small and large intestine in structure?

Answer 30

* Small intestine is longer and narrower * Large intestine is shorter and wider

Question 31

What is the function of salivary amylase?

Answer 31

Starch → maltose in the mouth.

Question 32

What is the function of pepsin?

Answer 32

Proteins → peptides in the stomach.

Question 33

What is the function of pancreatic amylase?

Answer 33

Starch → maltose in the small intestine.

Question 34

What is the function of trypsin?

Answer 34

Peptides → amino acids in the small intestine.

Question 35

What is the function of lipase?

Answer 35

Fats → fatty acids in the small intestine.

Question 36

Why does digestion of proteins begin in the stomach and not earlier?

Answer 36

Because pepsin is only active in acidic pH, which is present in the stomach.

Question 37

Why can lipids not dissolve directly into blood like glucose?

Answer 37

Because they are hydrophobic; they are absorbed into lymph via lacteals.

Question 38

Why is bicarbonate released into the small intestine?

Answer 38

To neutralize acidic chyme from the stomach and protect intestinal lining.

Question 39

What would happen if bile production stopped?

Answer 39

Fat digestion would be impaired due to lack of emulsification.

Question 40

Liver

Answer 40

Bile production, bile salts production

Question 41

Gall bladder

Answer 41

stores bile, releases bile

Question 42

Pancreas

Answer 42

secrete pancreatic juices which neutralize stomach acid

Question 43

The esophagus and stomach are separated by a

Answer 43

sphincter

Question 44

Gastric juice consists of

Answer 44

hydrochloric acid, pepsin, intrinsic factor, lipase

Question 45

HCL converts

Answer 45

pepsinogen (released by gastric gland) into pepsin

Question 46

Pepsin is

Answer 46

able to breakdown proteins in the stomach

Question 47

For vitamin B12 absorption

Answer 47

the intrinsic factor is needed (produced by gastric glands)

Question 48

Vitamin B12 is absorbed by the

Answer 48

small intestine

Question 49

Chyme

Answer 49

semi fluid mass of partially undigested food

Question 50

pyloric sphincter

Answer 50

separates stomach and small intenstine

Question 51

In the first section of the small intenstine

Answer 51

the duodenum bile and pancreatic secretions are mixed the chyme via the ampulla of vater

Question 52

Hydrogencarbon is able

Answer 52

to neutralize the acid in the chyme and produce the optimum pH value of 7-8

Question 53

Enterokinase released by the duodenum wall

Answer 53

changes the proenzyme tripsinogen to tripsin which can split proteins

Question 54

alpha amylase

Answer 54

converts carbohydrates to maltose and isomaltose

Question 55

Pancreatic lipase is able to split triglycerides to

Answer 55

two fatty acids

Question 56

Lumes of the small intenstine are covered with

Answer 56

vili

Question 57

Vili are about

Answer 57

1 mm long

Question 58

some nutrients such as Glucose

Answer 58

do not require a carrier

Question 59

nutrients like iron

Answer 59

require carriers like transferrin

Question 60

fats are transported by chylomicrons

Answer 60

chylomicrons

Question 61

The ileum does not have

Answer 61

circular folds

Question 62

The ileum absorbs

Answer 62

electrolytes such as calcium, trace elements such as zinc, and vitamins such as B12, and remaining bile acid

Question 63

Bile acid is transported back to the liver via

Answer 63

blood stream

Question 64

The food going through the esophagus, the food is transported by

Answer 64

peristalsis

Question 65

segmentation contractions

Answer 65

mix the chyme

Question 66

the large intestine is connected to the small intestine via

Answer 66

the bauhin's valve

Question 67

The large intestine does not have any

Answer 67

vili

Question 68

Through peristalsis the chyme is transported

Answer 68

from the ascending colon to the transverse colon to the descending colon

Question 69

Throughout going the colon

Answer 69

water is removed