GI Tract

Question 1

Name the 6 functions of the GI tract.

Answer 1

Ingestion, mechanical procession, digestion, secretion, absorption, excretion

Question 2

What is the mouth made up of?

Answer 2

Tongue, three pairs of salivary glands

Question 3

Name the 4 functions of chewing in the mouth

Answer 3

• Mechanical chewing
• Saliva lubricates the mouth
• Saliva moistens the food (helps us taste)
• Enzymes begin breaking down the starch in our food

Question 4

What is the name of the enzyme in our mouth?

Answer 4

Salivary amylase

Question 5

Where do you want the food to pass when you swallow?

Answer 5

Mouth, pharynx, esophagus, stomach

Question 6

Where don’t you want the food to pass?

Answer 6

Trachea, airway

Question 7

What closes the airway during swallowing?

Answer 7

Epiglottis

Question 8

After chewing, what do we call the food now?

Answer 8

Bolus

Question 9

What is the small intestine composed of?

Answer 9

1) Duodenum
2) Jejunum
3) Illeum

Question 10

Describe the structure of the walls of the stomach

Answer 10

Muscular, thick walls

Question 11

What kind of gland is the pancreas?

Answer 11

Exocrine, secretes something through a tube

It is an endocrine gland as well (directly into the bloodstream)

Question 12

What does the pancreas secrete?

Answer 12

Pancreatic juice and sodium bicarbonate

Question 13

Where does pancreatic juice go? What does it do?

Answer 13

Goes to the small intestine, their enzymes will break down the macronutrients

Question 14

Where does bicarbonate go? What does it do?

Answer 14

Neutralizes acidic pH from the stomach

Question 15

What does the liver do?

Answer 15

Produces bile

Question 16

What does the gallbladder do?

Answer 16

Stores bile

Question 17

Where does bile go? What does it do?

Answer 17

Small intestine, emulsify fatty foods from stomach

Question 18

Define peristalsis.

Answer 18

Coordination of movements by the smooth muscles of the GI track to push food down

Question 19

Is the esophagus closed?

Answer 19

normally closed, will open to let and KEEP the food + acid in the stomac

Question 20

What is the food called after it has passed through the stomach?

Answer 20

chyme

Question 21

What does the pyloric valve do?

Answer 21

Keeps the food in the stomach and GRADUALLY into the duodenum

Question 22

Where is gastrin produced?

Answer 22

Stomach

Question 23

What does gastrin signal the stomach cells to do?

Answer 23

increase peristalsis and secrete HCL

Question 24

What stimulates gastrin?

Answer 24

Food in the stomach

Question 25

What is the role of HCl in the stomach?

Answer 25

Breaks pepsnogen to pepsin (active)

Question 26

Name the 3 roles of gastrin.

Answer 26

1) Signals cells to increase peristalsis 2) Tells cells to secrete HCl 3) Tells other cells to secrete mucus (protect)

Question 27

Why is it so important to have mucus in the stomach?

Answer 27

Protective layer between HCl and cells

Question 28

Why is the production of intrinsic factor so necessary? Who stimulates it?

Answer 28

Gastrin stimulates, it binds to vitamin B12 and helps absorb

Question 29

Describe gastrin's negative feedback loop

Answer 29

Food stimulates gastrin -> gastrin stimulates release of HCl -> pH=1.5 -> negative feedback -> gastrin will STOP stimulation of HCl

Question 30

Where is the pyloric sphincter? What is its function?

Answer 30

One way valve from the stomach to the small intestine | When vomiting, nothing comes back up from past the stomach due to the sphincter

Question 31

How does the small intestine hold? Stomach? What are these tissues made of?

Answer 31

Full of fat Small intestine: ligaments and mesentary Stomach: lesser omentum and greater omentum

Question 32

Each fold has a ____ projection

Answer 32

fingerlike

Question 33

What is another word for fold?

Answer 33

plica circulares

Question 34

What is a crypt?

Answer 34

Hole in between the villi

Question 35

What do goblet cells produce?

Answer 35

Mucus

Question 36

What do arteries/veins do in the villus?

Answer 36

Artery absorbs nutrients, veins give away

Question 37

How long do intestinal epithelial cells live?

Answer 37

3 days (short but active lives)

Question 38

What does the lymphatic vessel in the villus do?

Answer 38

high fats, non soluble in H2O, are transported back to the heart via the thoracic duct

Question 39

Where do the last steps of digestion occur?

Answer 39

Microvilli (brush border)

Question 40

Why are microvilli useful for absorption?

Answer 40

+ surface area, + absorption

Question 41

What stimulates secretin?

Answer 41

The chyme hitting the walls of the duodenum

Question 42

What is the role of secretin?

Answer 42

Signals the pancreas to release pancreatic juice

Question 43

Where is secretin released from?

Answer 43

Duodenum

Question 44

Describe lipases, amylases, and proteases.

Answer 44

Lipases: digests lipids Amylases: digests starch + carbs Proteases: proteins -> peptides

Question 45

What does CCK stand for?

Answer 45

Cholecystokinin

Question 46

What stimulates CCK?

Answer 46

Fatty chyme

Question 47

What is the role of CCK?

Answer 47

Signals the gallbladder to contract and release bile

Question 48

Name the 3 ways nutrients can be absorbed across a cell membrane.

Answer 48

1) Cell diffusion (simple diffusion) 2) Facilitated diffusion 3) Active Transport

Question 49

Which ways to absorb nutrients don't require energy? Which do?

Answer 49

Energy: Active transport | No energy: cell diffusion, facilitated diffusion

Question 50

Which sphincter can we control?

Answer 50

Rectum/anus

Question 51

Name the 4 functions of the colon.

Answer 51

Reabsorption Transforms intestinal content -> feces Absorption of important vitamins Storage of fecal matter

Question 52

What are the roles of microbiota?

Answer 52

Autoimmune diseases, obesity

Question 53

What does the colon "lack" compared to the GI tract?

Answer 53

No villi

Question 54

Define probiotics.

Answer 54

microorganisms in foods and supplements that in sufficient quantities are beneficial to health

Question 55

Define prebiotics.

Answer 55

Foods that are undigested in the small intestine, but used as food for bacteria in the colon, stimulating their growth and activity

Question 56

What is the pH of blood, gastric juice, bile and saliva?

Answer 56

Blood: 7.4 Gastric Juice: 1.5 Bile: 8.5 Saliva: 6.5

Question 57

What happens during the stage of development of a nutrient deficiency resulting from inadequate intake?

Answer 57

Declining nutrient stores Abnormal functions within the body Overt signs