Lec 1 - GI tract

Question 1

what is an essential nutrient?

Answer 1

component of food deemed to be essential to life & physiological functions

Question 2

what happens if the diet lacks essential nutrients?

Answer 2

results in physiological dysfunction, impaired growth, impaired reproductions &/or organismal demise

Question 3

what is metabolism?

Answer 3

refers to the chemical conversions that occur with the cell & their associated changes in energy “the chemistry of life”

Question 4

what is nutrition?

Answer 4

refers to how an organism acquires adequate nutrient intakes to facilitate physiological function

Question 5

what are the essential nutrients (“required for life”)?

Answer 5

energy, certain fatty acids & amino acids, vitamins; minerals

Question 6

True or False: Carbohydrates are an essential nutrient

Answer 6

Flase: carbohydrates are not an essential but can contribute essential energy

Question 7

what macromolecules are our bodies composed of?

Answer 7

lipids, proteins, nucleic acids, & carbohydrates

Question 8

True or False: we cannot synthesize these macromolecules from nothing

Answer 8

true

Question 9

what micronutrients are essential components of food?

Answer 9

vitamins & minerals

Question 10

what are vitamins & minerals required for?

Answer 10

as cofactors & substrates in metabolic reactions, important signaling molecules, and influence cellular homeostasis through several mechanisms

Question 11

what must our digestive tract to for cell to absorb nutrients?

Answer 11

be able to break down food components into their minimally absorbable forms

Question 12

the digestive system ecology and immunotolerance:

Answer 12

the digestive tract is in contact with the outside world & a huge ecosystem of microorganisms & how the immune system can sense a friend vs foe

Question 13

the digestive system cell proliferation:

Answer 13

the digestive tract rapidly turns over, maintaining a high proliferative capacity for decades
fundamental for understanding pathways such as the Wnt signaling pathway

Question 14

the digestive system neurobiology:

Answer 14

vagus nerve allows coordination between brain & gut

Question 15

What organs are in the GI tract?

Answer 15

oral cavity
esophagus
stomach
small intestine
large intestine
anus

Question 16

Of the organs in the GI tract which is an accessory?

Answer 16

oral cavity

Question 17

what other organs form part of the small intestine

Answer 17

liver gallbladder pancreas

Question 18

what is digestion?

Answer 18

physical & chemical -> reduce size of molecules & repackage to facilitate absorption

Question 19

what is absorption?

Answer 19

movement from GI tract to blood or lymph

Question 20

what is secretion?

Answer 20

movement into lumen of GI tract

Question 21

what is motility?

Answer 21

muscles mix & move contents via peristalsis

Question 22

what is barrier

Answer 22

between external & internal environments

Question 23

how does the GI tract keep itself organized?

Answer 23

by having layers, made of several issue types, contains different cell types

Question 24

what are common layers of the GI tract

Answer 24

mucosa
submucosa
muscularis
adventitia (esophagus) or serosa (stomach, intestine)

Question 25

what are the different tissue types of the GI tract

Answer 25

epithelia connective vascular lymphatic muscle nerve

Question 26

epithelia tissue

Answer 26

various cell types responsible for secretion of hormones, enzymes

Question 27

connective tissue

Answer 27

forms supportive structure for tissues, facilitate storage, transport & signalling

Question 28

vascular tissue

Answer 28

facilitates absorption & transport of compounds & cells

Question 29

lymphatic tissue

Answer 29

transports lipids, interstitial fluid; facilitates immune function

Question 30

muscle tissue

Answer 30

smooth & striated muscle to process, mix & move food along the GI tract

Question 31

nerve tissue

Answer 31

neural & glial cells grouped into plexuses to coordinate various gut functions

Question 33

functions of the oral cavity

Answer 33

chewing (mastication) initiate digestion swallowing

Question 34

what neural aspects of the oral cavity cause disease status?

Answer 34

disruption of neural control/coordination of bolus formation & swallowing

Question 35

functions of salivary glands

Answer 35

chewing initiate digestion swallowing

Question 36

functions of saliva

Answer 36

glycoproteins lubricate & prevent abrasion salivary amylase initiates digestion of starch antimicrobial agents reduce risk of infection acts as pH buffer

Question 37

what occurs with inadequate saliva production

Answer 37

causes discomfort & impact swallowing capacity

Question 38

causes of inadequate saliva production

Answer 38

numerous medications autoimmune disease (Sjogren's) radiation exposure nerve damage

Question 39

what occurs during swallowing

Answer 39

peristalsis

Question 40

smooth muscle cells rhythmically contract to generate?

Answer 40

peristaltic waves

Question 41

what is contraction controlled by?

Answer 41

input from mechanical, chemical, & electrical stimuli

Question 42

what is essential to facilitate digestion?

Answer 42

continuity of the esophagus & its connection to the stomach

Question 43

what is the most common congenital anomaly?

Answer 43

esophageal atresia

Question 44

what is the goal of the stomach?

Answer 44

form chyme

Question 45

what is chyme

Answer 45

foot & secretions

Question 46

what is able to sense the presence of food in the stomach

Answer 46

mechanoreceptors

Question 47

how does the stomach digest

Answer 47

secretion of acid, pepsinogen, & gastric lipase

Question 48

what are the 4 additional functions of the stomach?

Answer 48

1. store food 2. kill bacteria 3. some absorption/ metabolism of ethanol 4. absorption of drugs & other small water-soluble compounds

Question 49

what makes up the gastric juice (6)

Answer 49

HCl, pepsinogen, mucus, water, electrolytes, & bicarbonate

Question 50

what is pepsinogen

Answer 50

an inactive precursor

Question 51

what is pepsin

Answer 51

is a protease with a pH optimum of 2 & induces activation

Question 52

what are gastric secretion regulated by

Answer 52

endocrine & nervous signals

Question 53

what are the 3 phases that gastric secretions are regulated in

Answer 53

cephalic, gastric, & intestinal

Question 54

what is the cephalic phase?

Answer 54

prior to food entering the stomach

Question 55

what is the gastric phase?

Answer 55

good's presence in the stomach

Question 56

what is the intestinal phase?

Answer 56

as food moves into the duodenum from the stomach

Question 57

True or False: H & Cl are exerted together

Answer 57

false, H20 dissociates into H+ & chloride is directly taken up with HCO3-

Question 58

which amino acid is essential

Answer 58

histidine

Question 59

______ is an essential vitamin & acts as a coenzyme to facilitate the decarboxylation reaction

Answer 59

pyridoxal phosphate

Question 60

what does gastrin do?

Answer 60

regulate histidine decarboxylase synthesis in the ECL cell

Question 61

what does somatostatin?

Answer 61

inhibits HCl production

Question 62

what type of cells secretes H+ & Cl-

Answer 62

parietal cells

Question 63

what nerve regulates acetylcholine?

Answer 63

vagal nerve

Question 64

what cell regulates histamine

Answer 64

ECL cells

Question 65

what cells regulate gastrin

Answer 65

G-cells

Question 66

which cells regulate somatostatin

Answer 66

D-cells

Question 67

what has a positive regulation of stomach acidification

Answer 67

vagal nerve, ECL & G-cells

Question 68

what has a negative regulation of stomach acidification

Answer 68

D-cells

Question 69

What does GERD stand for

Answer 69

gastroesophageal reflux disease

Question 70

what is GERD also commonly known as

Answer 70

acid reflux/heartburn

Question 71

what do chief cells produce

Answer 71

pepsinogen & gastric lipase

Question 72

what do goblet cells produce

Answer 72

mucous mucin

Question 73

what to parietal cells produce

Answer 73

HCl & intrinsic factor

Question 74

what to D-cells produce

Answer 74

somatostatin

Question 75

what do ECL cells produce

Answer 75

histamine & serotonin

Question 76

what do G-cells produce

Answer 76

gastrin

Question 77

what occurs during gastric emptying

Answer 77

passage from the stomach to the small intestine

Question 78

how long does emptying following a meal take

Answer 78

2-4 hours

Question 79

where does food leave during gastric emptying

Answer 79

pylorus

Question 80

what factors influence the rate of gastric emptying

Answer 80

nervous reflexes sensitive to distension of the duodenum & hormonal

Question 81

what is the primary function of the small intestine

Answer 81

main site of nutrient digestion & absorption

Question 82

how does the small intestine facilitate lipids absorption

Answer 82

packages food components into easily absorbable

Question 83

what are the 3 different parts of the small intestine?

Answer 83

duodenum, jejunum, ileum

Question 84

what are the 4 parts of the intestinal wall in the small intestine

Answer 84

mucosa, submucosa, muscularis, serosa

Question 85

what does the mucosa do

Answer 85

absorptive/ secretory layer

Question 86

what does the submucosa layer do

Answer 86

vascular connective tissue

Question 87

what does the muscularis layer do

Answer 87

peristaltic movement do

Question 88

what does the serosa layer do

Answer 88

protective layer