Digestion

Question 1

what is the pathway food takes through the gastrointestinal tract?

Answer 1

mouth -> pharynx -> esophagus -> cardiac sphincter -> stomach -> pyloric sphincter -> small intestine -> large intestine -> rectum -> anus

Question 2

how long is the digestive system?

Answer 2

between 6.5m and 9m

Question 3

what are the accessory organs?

Answer 3

1. pancreas
2. gall bladder
3. liver
   - organs that are along the digestive tract but that food does not pass through

Question 4

how long does it take to go from one end of the tube to the other?

Answer 4

24-72 hours

Question 5

what are the 4 steps of digestion?

Answer 5

1. Ingestion
2. Digestion
3. Absorbtion
4. Egestion

Question 6

what is ingestion?

Answer 6

the taking of nutrients (eating)

Question 7

what is digestion?

Answer 7

the breakdown of organic molecules into smaller complexes

Question 8

what is absorption?

Answer 8

the transport of digested nutrients to the tissues of the body

Question 9

what is egestion?

Answer 9

the removal of materials from the food that the body cannot digest (pooping)

Question 10

what is mechanical digestion?

Answer 10

• breaking food into tiny pieces without changing the chemical structure of the food
• increases the surface area to expose the nutrients to the digestive chemicals
• AKA. chewing

Question 11

what is chemical digestion?

Answer 11

food molecules are broken into smaller and smaller particles using enzymes (bonds are broken)

Question 12

what does starch get broken down to?

Answer 12

monosaccharides

Question 13

what does protein get broken down to?

Answer 13

amino acids

Question 14

what do lipids get broken down to?

Answer 14

fatty acids and glycerol

Question 15

what is the function of the mouth?

Answer 15

• the first step of mechanical digestion

Question 16

what is mastication?

Answer 16

chewing your food

Question 17

what is chewed food called?

Answer 17

bolus

Question 18

how does taste work?

Answer 18

• our tongue is covered with tastebuds

- these identify the tastes of specific chemicals in our food with the help of our nose

Question 19

what is the pharynx?

Answer 19

• intersection for nose, mouth, esophagus, epiglottis and trachea
• AKA. throat

Question 20

what is the esophagus?

Answer 20

a long tube lined with muscle

Question 21

what is the function of the esophagus?

Answer 21

the muscle pinches to push the food down to the stomach

Question 22

what is peristalsis?

Answer 22

muscular contractions and relaxations that push food down to the stomach

Question 23

what does the cardiac/esophageal sphincter do?

Answer 23

regulates how many bolus enter the stomach at a time

Question 24

why does the lower esophageal sphincter relax at the bottom of the esophagus?

Answer 24

so that no food can travel from the stomach back up the esophagus

Question 25

what is an esophageal ulcer?

Answer 25

when stomach acid burns a hole in the esophagus

Question 26

what is heartburn?

Answer 26

when the bolus/stomach acid moves backward toward the heart causing a burning sensation in the esophagus

Question 27

what does the pyloric sphincter do?

Answer 27

controls how much food enters the small intestine

Question 28

what is the structure of the stomach?

Answer 28

- it is a J-shaped sack like organ | - 50mL --> 2L --> 4L

Question 29

what is the function of the stomach?

Answer 29

- storage - digestion (mechanical + chemical) - pushes food to the small intestine - produces pepsin, HCl and mucus - digests proteins

Question 30

what macromolecule gets digested in the mouth?

Answer 30

starches into monosaccharides

Question 31

what macromolecule gets digested in the stomach?

Answer 31

proteins into amino acids

Question 32

what do peptic cells do?

Answer 32

secretes pepsinogen (inactive enzyme), which mixes with HCl to create pepsin (active enzyme), the pepsin then breaks down the proteins

Question 33

what is the pH of the stomach?

Answer 33

1-3

Question 34

what do parietal cells do?

Answer 34

- secretes HCl - maintains stomach pH - kills bacteria - activates pepsinogen into pepsin

Question 35

which cell secretes pepsinogen?

Answer 35

peptic

Question 36

which cell secretes HCl?

Answer 36

parietal

Question 37

what do mucus cells do?

Answer 37

secrete mucus to make stomach lining

Question 38

how often are the stomach cells destroyed and remade?

Answer 38

every 3-4 days

Question 39

what does gastric juice consist of?

Answer 39

water, mucus, salts, HCl and enzymes

Question 40

what is chyme?

Answer 40

- liquified food + gastric juices | - what the stomach releases to the small intestine

Question 41

what does the pancreas do?

Answer 41

- produces digestive enzymes | - continues the digestion of starches, lipids and proteins

Question 42

what does the liver do?

Answer 42

- produces bile and send it to the gall bladder for storage - stores glycogen - detoxifies many substances in the body

Question 43

what does the gall bladder do?

Answer 43

stores + releases bile

Question 44

what is bile?

Answer 44

grinds lipids to small pieces (fatty acids + glycerol)

Question 45

what is the structure of the small intestine?

Answer 45

- small tube made of smooth muscle | - smaller in diameter than the large intestine

Question 46

what are villi?

Answer 46

finger-like projections in the membrane of the small intestine

Question 47

what is the function of the small intestine?

Answer 47

the absorption of monosaccharides, fatty acids +glycerol and amino acids

Question 48

what does the large intestine do?

Answer 48

- pushes undigested food/waste/feces to the rectum | - absorbs water back into the body

Question 49

what are the three segments of the small intestine?

Answer 49

1. duodenum 2. jejunum 3. ileum

Question 50

what is the function of the duodenum?

Answer 50

- receives chyme from the stomach | - most mechanical and chemical digestion occurs here

Question 51

what is the function of the jejunum?

Answer 51

- continues the breakdown, most absorption occurs here

Question 52

what is the function of the ileum?

Answer 52

absorbs nutrients and pushes undigested material to large intestine

Question 53

what chemical digestion occurs in the duodenum?

Answer 53

enzymes break down carbohydrates

Question 54

what hormones are released in the duodenum?

Answer 54

- secretin | - CCK

Question 55

what are the two networks and where are they?

Answer 55

- in the small intestine | - capillary and lymph

Question 56

what does the capillary network do?

Answer 56

absorbs amino acids and monosaccharides

Question 57

what does the lymph network do?

Answer 57

absorbs fatty acids and glycerol

Question 58

where are amino acids absorbed?

Answer 58

in the villi of the small intestine

Question 59

where is glucose absorbed?

Answer 59

in the villi of the small intestine

Question 60

what is the structure of the pancreas?

Answer 60

feather-like organ under the stomach on top of the small intestine

Question 61

what is the structure of the liver?

Answer 61

has 4 lobes

Question 62

what is the structure of the large intestine?

Answer 62

wider than the small intestine, but only about 1.5m long

Question 63

what are the measurements of the small intestine?

Answer 63

7m x 2.5cm

Question 64

what do hormones do?

Answer 64

control how we process, digest and absorb food

Question 65

what does the colon do?

Answer 65

absorbs water and salts

Question 66

what happens when we absorb too much water?

Answer 66

constipation

Question 67

what happens when we don't absorb enough water?

Answer 67

diarrhea

Question 68

what does the rectum do?

Answer 68

receives and stores digested material before elimination

Question 69

what does emulsify mean?

Answer 69

grinding into smaller pieces to increase surface area (bile)