The GI Tract

Question 1

What is our main source of energy?

Answer 1

calories

Question 2

What are carbohydrates?

Answer 2

our primary fuel source

Question 3

What are the two things we can do with carbohydrates?

Answer 3

1. burn in mitochondria for ATP
2. store as fat for later

Question 4

What are fats used for?

Answer 4

energy storage

Question 5

Are fats more efficient than carbs and proteins? By how much?

Answer 5

yes, they are! they are 2x as efficient

Question 6

What are the three overarching essential ingredients we need to function?

Answer 6

1. protiens
2. vitamins
3. minerals

Question 7

What are proteins used for?

Answer 7

to break down into amino acids

Question 8

How many amino acids can your body make?

Answer 8

11/20, so the rest you have to eat

Question 9

What are vitamins?

Answer 9

organic substances that CAN’T be made by the body

Question 10

What are minerals?

Answer 10

inorganic substances that CAN’T be made by the body

Question 11

What is the GI tract?

Answer 11

digestive system (mouth to anus)

Question 12

What do accessory organs do in the GI tract?

Answer 12

they help secrete enzymes that aide digestion

Question 13

What are some accessory organs?

Answer 13

1. liver
2. gallbladder
3. salivary gland
4. pancreas

Question 14

What is the lumen?

Answer 14

the hole running through the GI tract

Question 15

What is the mucosa?

Answer 15

inner layer of the GI tract that secretes mucus, protects other layers, and absorbs nutrients

Question 16

What type of tissue is the mucosa?

Answer 16

epithelial

Question 17

What is the submucosa?

Answer 17

2nd innermost layer, that has lymphatic, nerve, and blood vessels

Question 18

What type of tissue is the submucosa?

Answer 18

connective

Question 19

What is the muscularis layer?

Answer 19

the 3rd innermost layer that has circular and longitudinal muscles for pushing food down

Question 20

What type of tissue is the muscularis layer?

Answer 20

smooth muscle tissue

Question 21

What is the serosa?

Answer 21

outermost layer, protects tract from the outside

Question 22

What type of tissue is the serosa?

Answer 22

epithelial

Question 23

What is the beginning of digestion?

Answer 23

when salivary glands secrete enzymes

Question 24

What if you have no teeth for food breakdown?

Answer 24

no problem, some birds swallow pebbles and do the mechanical breakdown in their gizzard

Question 25

What is the salivary gland controlled by?

Answer 25

your brain

Question 26

How does swallowing start and end?

Answer 26

it starts voluntary and ends involuntary

Question 27

What does the esophagus do?

Answer 27

connects pharynx to stomach

Question 28

What happens to the esophagus when you swallow?

Answer 28

your brain tells the esophagus to send one way waves to move food downwards

Question 29

What is a sphincter?

Answer 29

openings that let food in and then close itself, so that food doesn't travel backwards

Question 30

What is the entrance to the stomach from the esophagus?

Answer 30

the esophageal sphincter

Question 31

What happens in the stomach to the food?

Answer 31

gastric juices mix with food

Question 32

What does HCl do in the stomach and where does it come from?

Answer 32

it creates the low pH environment in the stomach and it is secreted from the parietal cells

Question 33

What other gastric molecule is in the stomach?

Answer 33

pepsinogen

Question 34

Is pepsinogen active or inactive?

Answer 34

inactive, the stomach keeps it that way until the food arrives because you don't want to digest your own stomach

Question 35

How is pepsinogen turned active?

Answer 35

when our stomach becomes acidic by the HCl and pepsinogen turns into pepsin

Question 36

What cells does pepsinogen come from?

Answer 36

chief cells

Question 37

Does the stomach absorb nutrients from the food?

Answer 37

no, that happens in the small intestine

Question 38

What are the three parts of the small intestine?

Answer 38

1. duodenum 2. jejunum 3. ileum

Question 39

What does the duodenum do?

Answer 39

fats are broken down here with accessory organs pancreas and gallbladder

Question 40

What does the jejunum do?

Answer 40

this is where absorption officially starts

Question 41

What does the ileum do?

Answer 41

absorbs more nutrients

Question 42

Is the small intestine small?

Answer 42

nope, it has a huge surface area and it's about the size of a tennis court

Question 43

What do the villi and microvilli do?

Answer 43

hair like structures in the small intestine that increases absorption and it is called the "brush border"

Question 44

What are proteins and carbs broken down by?

Answer 44

the brush border enzymes

Question 45

Where do the broken down proteins and carbs go?

Answer 45

they are transported into cells and then into the blood stream

Question 46

What emulsifies fats in the small intestine?

Answer 46

bile salts

Question 47

What enzymes break down the fats into fatty acids?

Answer 47

lipase enzymes

Question 48

What happens to the fats after breakdown?

Answer 48

it diffuses across the membrane and is packed into transport proteins

Question 49

What are chylomicrons?

Answer 49

transport proteins that fatty acids are packed into

Question 50

Where does the fatty acid enter?

Answer 50

the lymph system first and then the circulatory system

Question 51

What does the pancreas do for the small intestine?

Answer 51

secretes enzymes "pancreatic juice" into the duodenum via the pancreatic duct

Question 52

What are some enzymes that the pancreas secretes?

Answer 52

bicarbonate, trypsin, amylase, and lipase

Question 53

What does bicarbonate do?

Answer 53

neutralizes stomach acids (after the food enters the small intestine)

Question 54

What does trypsin do?

Answer 54

aids with digestion

Question 55

Is trypsin stored actively or inactively?

Answer 55

inactively

Question 56

What kind of environment is amylase and lipase activated by?

Answer 56

basic (alkaline) environment

Question 57

Before the nutrients get distributed throughout the body, what must they pass through first?

Answer 57

the liver

Question 58

What is the main function of the liver?

Answer 58

detoxification

Question 59

What does the liver regulate?

Answer 59

glucose levels

Question 60

If there's too much glucose, what does the liver do?

Answer 60

make glycogen

Question 61

If there's too little glucose, what does the liver do?

Answer 61

break down glycogen

Question 62

What else does the liver do?

Answer 62

makes plasma proteins and filters dead bile pigments

Question 63

What is the large intestine also called?

Answer 63

the colon

Question 64

How large is the large intestine compared to the small one?

Answer 64

shorter but wider than the small intestine

Question 65

What does the colon do?

Answer 65

absorbs the last of the water, electrolytes, and vitamin k & compacts feces

Question 66

What is attached to the colon?

Answer 66

cecum and appendix

Question 67

Do we have a cecum?

Answer 67

no

Question 68

What does the cecum do?

Answer 68

helps digest cellulose

Question 69

What 2 sphincter muscles control the rectum?

Answer 69

a voluntary and involuntary muscle

Question 70

What is feces composed of?

Answer 70

water, mucus, bacteria. and bile pigments

Question 71

What do herbivores have in order to digest cellulose?

Answer 71

longer digestive tracts and a longer cecum

Question 72

What do ruminants have to help digest cellulose?

Answer 72

4 chambered stomachs

Question 73

What doe carnivores have because they don't really eat plants?

Answer 73

shorter intestinal tracts (also because they chan tear and chew food)

Question 74

What is coprophagy?

Answer 74

when animals eat feces to absorb more nutrients

Question 75

What does ghrelin do?

Answer 75

stimulates hunger and feeding and it is released from the stomach to the brain

Question 76

What does leptin do?

Answer 76

tells CNS to limit food intake (high body fat=high levels of leptin)

Question 77

What is BMR?

Answer 77

calories needed by your body to perform basic functions

Question 78

What is the difference between Calorie and calorie?

Answer 78

Calorie = kcal calorie = cal

Question 79

When does transition between voluntary to involuntary digestion occur?

Answer 79

when the food goes from the oral cavity to the pharynx

Question 80

How does swallowing affect breathing?

Answer 80

you momentarily hold your breath, when swallow, to close the airway so that food doesn't go to your lungs

Question 81

What is peristalsis?

Answer 81

the motion of moving food down your esophagus

Question 82

Where are the bile salts made and stored?

Answer 82

made in the liver but stored in the gallbladder

Question 83

What is gastrin?

Answer 83

hormone that stimulates the secretion of gastric juices into the stomach

Question 84

What cells does gastrin target?

Answer 84

it targets chief and parietal cells because they're the ones that secrete HCl and pepsin

Question 85

What is CKK and what does it do?

Answer 85

it is a hormone that stimulates the release of pancreatic juices

Question 86

What does GIP do?

Answer 86

it's a hormone that responds to ingestion of glucose (it increases intake and absorption of nutrients)

Question 87

What is secretin and what does it do?

Answer 87

regulates and secretes bicarbonate into the duodenum