Gastrointestinal System

Front 1

what are the 7 major organs of the GI system?

Back 1

1. mouth

2. esophagus

3. stomach

4. small intestine

5. large intestine

6. rectum

7. anus

Front 2

what are the major functions of the GI system?

Back 2

break down food

prepare food for uptake by body's cells

provide body water

eliminate waste

Front 3

what are the histological features of the GI tract?

Back 3

mucosa

submucosa

muscularis

serosa

enteric plexus

Front 4

what are the functions of saliva?

Back 4

dilutes sour taste (neutralizes bacterial acids), prevents tooth decay, initiates carbohydrate digestion through a-amylase, prevents infection through IgA

Front 5

what are the 2 phases of swallowing?

Back 5

1. oropharyngeal phases

2. esophageal phase

Front 6

describe the oropharyngeal phases of swallowing?

Back 6

voluntary phase where pharynx contracts and prevents food from entering nasopharynx, epiglottis slides down and prevents bolus into airway, tongue and pharybgeal constructors move food to esophagus

Front 7

describe the esophageal phase of swallowing.

Back 7

involuntary, food transported to stomach by means of sequential muscle contraction and relaxation

Front 8

compare primary and secondary peristalsis.

Back 8

primary peristalsis occurs immediately after the oropharyngeal phases of sawllowing; secondary peristalsis occurs when food becomes stuck and stretch receptors are activated to allow second wave of contractions and relaxations

Front 9

what are the 3 phases of gastric secretion?

Back 9

1. Cephalic phase

2. gastric phase

3. intestinal phase

Front 10

what happens on the cephalic phase of gastric secretion?

Back 10

Mouth; chewing, swallowing, smell, seeing food, taste

Front 11

what happens in the gastric phase of gastric secretion?

Back 11

Stomach; stretching, distention of stomach

Front 12

what happens in the intestinal phase of gastric secretion?

Back 12

Intestines; digested protein

Front 13

what are the effects of aging on the digestive function?

Back 13

tooth enamel and dentin wear down

teeth lost

peridontal disease

gum recession

osteoporotic Bone changes

decreased taste buds

decreased sense of smell

decreased salivary secretions

decreased gastric motility

Front 14

explain enterohepatic circulation of bile acids.

Back 14

majority of bile salts that go into the GI tract are recycled and taken back to the liver; liver-gallbladder-duodenum/jejunum-rectum/feces or to ileum/colon-hepatic portal vein-bavk to liver

Front 15

what is the major function of the gallbladder?

Back 15

stores and concentrates bile between meals (can hold 90ml of bile)

Front 16

what is ingestion?

Back 16

taking food into the body

Front 17

what is digestion?

Back 17

the process of breaking down food by mechanical and enzymatic (chemical) action into substances that can be used by the body

Front 18

what is absorption?

Back 18

the process by which digested food is able to pass into the blood vessels in the wall of the intestine through diffusion or active transport

Front 19

what is metabolism?

Back 19

the chemical processes that occur in the body in n order to harvest energy and maintain life.

Front 20

what is excretion?

Back 20

elimination of waste through defecation

Front 21

how does transporting epithelia work?

Back 21

epithelial cells line the parts of the GI tract ; the epithelia absorb nutrients, salt and water through diffusion and active transport in the small intestine ..those in the stomach secrete HCL acid

Front 22

what are the general cellular models of secretion?

Back 22

digestive enzymes are secreted and mucus glands from the mouth to anus provide mucus for lubrication and protection

Front 23

what are the general cellular models of fluid absorption?

Back 23

villi work in the small intestine to increase mucosal absorptive area; in large intestine there is water by diffusion

Front 24

describe the neural mode of control in the GI tract.

Back 24

Enteric nervous system/plexus:

gastrocolic reflex (stomach and colon communicate )

outer plexus=myenteric (controls GI movements )

inner plexus= submucosa (controls GI secretion and local blood flow )

Front 25

describe the endocrine mode of control in the GI tract.

Back 25

GI endocrine cells; ACh excites GI activity and NE inhibits it

Front 26

describe the paracrine mode of control in the GI tract.

Back 26

chemical messengers that stimulate nearby cells

Front 27

describe the innervations of the GI tract.

Back 27

parasympathetic innervations :

vagus nerve innervates the upper GI tract (esophagus-ascending colon)

pelvic nerve innervates the lower GI tract (transverse colon-anus)

Front 28

what is chewing?

Back 28

(mastication); process by which food is crushed and grounded by teeth into bolus; first step in digestion

Front 29

what is achalasia?

Back 29

failure of smooth muscle to relax, which causes the lower esophageal sphincter to remain closed and obstruct ; if the LES opens too often or doesn't close tight enough, stomach acid can reflux and cause heart burn

Front 30

what 2 things stimulate pepsinogen release.

Back 30

ACh and acid stimulate release of pepsinogen, which is converted to pepsin to break down proteins

Front 31

what is the gastric mucosal barrier?

Back 31

coating of mucus that protects the stomach from actions of acid and pepsin

Front 32

what agents are known to disrupt the gastric mucosal barrier?

Back 32

NSAIDS, H. pylori, etoh

Front 33

where are primary bile salts/acids synthesized?

Back 33

from cholesterol by the hepatocytes

Front 34

where are secondary bile acids/salts formed?

Back 34

in the small intestine

Front 35

how does bile get its greenish black color?

Back 35

billirubin, which is a byproduct of the destruction of aged red blood cells

Front 36

which enzymes break down carbohydrates?

Back 36

amylase

Front 37

which enzymes break down fats?

Back 37

lipase

bile

Front 38

which enzymes break down proteins?

Back 38

pepsin

trypsin

chymotrypsin

Front 39

what is osmotic diarrhea?

Back 39

results from poorly absorbed solutes (lactose common cause)

Front 40

what is malabsorption diarrhea?

Back 40

malabsorption of fatty acids (common cause is celiac disease )

Front 41

what is exudative diarrhra?

Back 41

large quantities of exudate like blood and pus (common cause is IBS, infection)

Front 42

where is the lower esophageal sphincter?

Back 42

between the esophagus and the stomach

Front 43

where Is the pyloric valve?

Back 43

between the stomach and duodenum

Front 44

where is the ileocecal valve?

Back 44

controls chyme from ileum to cecum

Front 45

where is the O Beirne sphincter?

Back 45

controls waste from the sigmoid to rectum