Structures and Functions of the Gastrointestinal System

Question 1

What are Etiologies of GI disorders?

Answer 1

-structural abnormality
-gut perfusion
-gut motility
-nutrient absorption
-neoplasia

Question 2

What are the types of structural abnormalities?

Answer 2

-congenital
-acquired (disease or surgery)
-traumatic

Question 3

Where are nutrients absorbed in the GI system?

Answer 3

small bowel (intestine)

Question 4

What are the functions of the GI system?

Answer 4

-ingestion, digestion, and absorption of nutrients
-elimination of wastes
-protection of immunity

Question 5

What is ingestion?

Answer 5

taking in food

Question 6

What is digestion?

Answer 6

breaking food down into nutrients

Question 7

What is absorption?

Answer 7

taking in nutrients by cells

Question 8

What is excretion?

Answer 8

elimination of metabolic waste

Question 9

What are the digestive organs?

Answer 9

mouth, pharynx, esophagus, stomach, small intestine, large intestine

Question 10

What is GI motility?

Answer 10

the movement of food and fluid through the length of the GI tract

Question 11

What does the enteric nervous system control?

Answer 11

the GI tract with influences from the autonomic nervous system and nerve fibers within the local structures

Question 12

How many layers are in the stomach?

Answer 12

3 layers of smooth muscle

Question 13

What is the stomach lined with?

Answer 13

mucosa that serves as a protective barrier

Question 14

What are the two sphincters of the stomach?

Answer 14

cardiac/esophageal and pyloric

Question 15

What does the cardiac sphincter do?

Answer 15

tight muscle keeps stomach acid from regurgitating back up in esophagus

Question 16

What does the pyloric sphincter do?

Answer 16

Regulates the movement of food and stomach acids into the small intestine

Question 17

What produces gastric juice?

Answer 17

HCL, pepsin, mucus

Question 18

What does hydrochloric acid do?

Answer 18

-breaks down food
-destroys invading bacteria or viruses
-converts pepsinogen made in gastric cells, into pepsin

Question 19

What does pepsin do?

Answer 19

breaks down proteins

Question 20

What does mucus do?

Answer 20

protects stomach lining from the hydrochloric acid it produces

Question 21

What is mechanical digestion?

Answer 21

churning of food into chyme; breakdown of food into smaller particles without any molecular change

Question 22

What does the stomach secrete?

Answer 22

intrinsic factor from parietal cells in mucosa lining to absorb Vitamin B12 in the ileum of small bowel

Question 23

Intrinsic factor + Vitamin B12=

Answer 23

RBC

Question 24

What is chemical digestion?

Answer 24

bigger molecules are dismantled into smaller molecules which become a different structure

Question 25

Increased motility and secretions of GI tract is a result of what?

Answer 25

parasympathetic stimulation through the vagus nerve

Question 26

What does sympathetic stimulation do to GI motility?

Answer 26

decreases

Question 27

What leads to decreased peristalsis?

Answer 27

decreased GI motility due to sympathetic stimulation

Question 28

What does pyloric sphincter prevent?

Answer 28

back flow of highly acidic gastric contents that have passed into duodenum

Question 29

What are examples of gastric motility disorders?

Answer 29

-gastroparesis -dumping syndrome -pyloric stenosis

Question 30

Gastroparesis

Answer 30

stomach emptying is too slow or absent

Question 31

Dumping Syndrome

Answer 31

consumed contents pass into small bowel too quickly

Question 32

Pyloric stenosis

Answer 32

tight pyloric valve prevents food from passing out of the stomach into the duodenum (can be congenital in infants and requires surgery)

Question 33

What are the 3 parts of the small intestine?

Answer 33

duodenum, jejunum, ileum

Question 34

What is the duodenum?

Answer 34

-contains openings for bile duct and main pancreatic duct -bile and pancreatic fluid enter intestine through ducts

Question 35

What is the jejunum?

Answer 35

-food is digested and majority of absorption occurs here -digested nutrients are absorbed through intestinal walls

Question 36

What is the ileum?

Answer 36

-food is digested and absorbed -compacts the leftover to pass through to large intestine

Question 37

What is the normal pH of large intestine?

Answer 37

6.5-7.5

Question 38

What is a major function of the large intestine?

Answer 38

water absorption from waste material

Question 39

What Vitamins are produced by intestinal bacteria?

Answer 39

Vitamin B and K

Question 40

What happens to the leftover waste in the large intestine?

Answer 40

it is compacted and stored in rectum

Question 41

What happens when rectum is full and sphincter relaxes?

Answer 41

waste is eliminated

Question 42

What is the major metabolic function of microflora in the colon?

Answer 42

fermentation of indigestible food and other digestible dietary residue

Question 43

Which colonic microorganisms play a role in vitamin production and absorption?

Answer 43

-calcium -magnesium -iron

Question 44

What do colonic microorganisms do?

Answer 44

provide a crucial line of defense against microorganisms that are consumed

Question 45

What does the use of large amount board spectrum antibiotics allow?

Answer 45

overgrowth of potential harmful pathogens- clostridium difficile

Question 46

What is the GI tract a main site for?

Answer 46

the internal body's contact with the external world

Question 47

What does the GI tract consume?

Answer 47

essential food and microbes, but also possible pathogenic organisms

Question 48

What is the stomach fluid pH?

Answer 48

1-4

Question 49

What is intestinal mucosa?

Answer 49

a physical, biochemical, and immune barrier

Question 50

What does intestinal tissue (Peyer's patches) contain?

Answer 50

immune cells including lymphocytes that protect against harmful consumed substances

Question 51

What does amylase in saliva do?

Answer 51

breaks down ingested starches into disaccharides

Question 52

What do disaccharides do?

Answer 52

digest disaccharides to monosaccharide by more amylase from the pancreas in the small bowel

Question 53

What happens when disaccharides are not broken down to monosaccharides?

Answer 53

they cannot be absorbed and remain active causing diarrhea

Question 54

Deficiency of lactase to breakdown lactose causes what?

Answer 54

diarrhea when eating dairy products

Question 55

What is emulsification?

Answer 55

break down of large fat globules into smaller sizes

Question 56

What is Steatorrhea?

Answer 56

fatty stools (indicates fat not absorbed)

Question 57

What do water-soluble enzymes act on?

Answer 57

fat in the stomach and continues in the duodenum with bile from the liver (breaks down fat)

Question 58

Is fat used for immediate energy?

Answer 58

no, it is stored as triglycerides

Question 59

What does elevated triglycerides mean?

Answer 59

calorie intake higher than body need

Question 60

Where does protein digestion begin?

Answer 60

in the stomach due to action of pepsin that breaks down in tact proteins into smaller amino acid chains called peptides

Question 61

Enzymes from the pancreas travel to the duodenum to do what?

Answer 61

mix with chyme to break down peptides to amino acids

Question 62

What absorbs amino acids into the blood?

Answer 62

the small bowel

Question 63

What controls the delivery of amino acids to various body sites?

Answer 63

the liver