Patho - Exam 6 Gastrointestinal Function

Front 1

Tracheoesophageal fistula:

Back 1

-congenital
-both trachea and esophagus have common origin
-2 types;
1. esophogeal atresia (esoph closed off)
2. fistula connecting with both tubes open

Front 2

What is the most frequent cause of intestinal obstruction in newborns?

Back 2

duodenal atresia

Front 3

Omphalocele:

Back 3

-herniation of visceral at base of umbilical cord

Front 4

Anal agenesis:

Back 4

-imperforate anus
-anus was not fully developed at birth
-corrected with surgery

Front 5

3 functions of saliva:

Back 5

-secreted by salivary glands
1. moisten for swallowing
2. allow for tasting
3. contains salivary amylase

Front 6

salivary glands consist of 4 glands:

Back 6

1. parotid glands
2. submaxillary glands
3. sublingual glands
4. buccal glands

Front 7

salivary amylase:

Back 7

-initiate the digestion of dietary starches
-converts polysaccharides to dextrin and maltose

Front 8

List the parts of the gastrointestines:

Back 8

1. oral cavity
2. pharynx
3. esophagus
4. stomach
5. small intestine
6. larger intestine

Front 9

Pharynx:

Back 9

-soft palate that moves upward with swallowing
-epiglottis closes
-muscles propel food

Front 10

Esophagus:

Back 10

(food has the right of way)
-mucus facilitates food passage
-strong peristalic action
-lower esophagus sphincter

Front 11

Lower esophagus sphincter:

Back 11

-prevents regurgiation
-physiological circular fibers
-not a true sphincter

Front 12

Parts of the stomach:

Back 12

1. cardia (opening of esoph to stomach)
2. fundus (left of cardia orifice)
3. body (central)
4. antrum (btn body and pylorus)

Front 13

pylorus:

Back 13

-orifice encircled by a ringlike muscle that opens into the small intestine

Front 14

Stomach glands:

Back 14

1. chief
2. parietal
3. mucous
4. gastrin

Front 15

chief glands:

Back 15

-stomach glands that secretes pepsinogen which converts to pepsin when exposed to low pH of the gastric juices

Front 16

parietal glands:

Back 16

-stomach glands secrete HCL and gastric intrinsic factor (necessary for the absorption of B12)

Front 17

mucous glands:

Back 17

-stomach glands that secrete mucous that are resistant to the highly acidic secretions

Front 18

gastrin glands:

Back 18

-secreted at antrum of stomach and duodenum
-hormone secreted by glands in the mucous membrane of the stomach
-stimulates the production of gastric acid

Front 19

Small intestine:

Back 19

-digestive and absorptive functions occur (most H2O is absorbed here)
-contain villi for surface area
-secretes digestive juices and receives secretions from the liver and pancreas
-fast cell turnover

Front 20

Brunner's glands:

Back 20

-mucus producing glands
-located at duodenum
-secrete large amounts of alkaline mucus protecting duodenum from acid content in the chyme and digestive enzymes
-influenced by ANS

Front 21

ileocecal valve:

Back 21

-valve prevents backflow of feces from the cecum into the small intestine

Front 22

4 Parts of the large intestine:

Back 22

1. cecum
2. colon (ascending, transverse, descending, sigmoid)
3. rectum
4. anal canal

Front 23

Function of large intestine:

Back 23

-no villi
-absorbs water and electrolytes (although most water is absorbed from the small intestine)

Front 24

5 Layers of intestinal wall:

Back 24

1. mucosa (muscularis mucosa)
2. submucosa
3. circular muscle
4. longitudinal muscle
5. serosa

Front 25

What 2 layers of the intestinal wall consist of smooth muscle?

Back 25

circular and longitudinal muscle

Front 26

What areas of the intestinal wall consist of skeletal muscle?

Back 26

mouth to proximal esophagus and anus

Front 27

Describe the electrical activity of the GI smooth muscle:

Back 27

-almost constantly present
-graded degree of intensity

Front 28

2 types of muscle contractions in the intestinal walls:

Back 28

1. tonic contractions
2. rhythmic contractions

Front 29

tonic contractions:

Back 29

-det amount of pressure in segment of bowel
-det amount of resistance in sphincters

Front 30

rhythmic contractions:

Back 30

-responsible for mixing and propulsion of contents
-degree varies

Front 31

intramural neurons:

Back 31

-contained within the wall of the gastrointestinal tract
-consist of 2 networks, myenteric and submucosal plexuses

Front 32

Auerbach's plexus:

Back 32

=myenteric plexus
-located btn muscle layers
-control GI movements

Front 33

Meissner's plexus:

Back 33

=submucosal plexus
-control secretions
-sensory functions such as stretch impulses

Front 34

afferent nerve fibers:

Back 34

-transmit information about GI tract
-respond to irritation, distention, presence of chemical substances
-may be exitatory or inibitory response

Front 35

Gastrin:

Back 35

-food entering stomach
-INCREASES;
1. gastric motility
2. constriction of LES (prevents reflux)
3. production of gastric glands

Front 36

Cholecystokinin:

Back 36

-from duodenal mucosa
-response to fatty substances
-increases contractility of gallbladder

Front 37

Secretin:

Back 37

-secreted in duodenum
-stimulated by entry of acidic juice from liver or pancreas
-neutralizes

Front 38

Gastric inhibitory peptide:

Back 38

-from upper intestinal mucosa
-responds to fat and some CHO
-decreases emptying stomach when there is an oversupply of nutrient substances

Front 39

2 types of intestinal movement:

Back 39

1. Peristalsis
2. mixing movements

Front 40

peristalsis:

Back 40

=propulsive
-stimulus is distention of intestinal walls
-circular constriction squeezes materials in front forward movement

Front 41

chewing:

Back 41

-mixes with saliva (bolus)
-action of teeth to change food to it's simplest, basic form

Front 42

3 stages of swallowing:

Back 42

1. oral stage
2. pharyngeal stage
3. esophageal stage

Front 43

Oral stage:

Back 43

-first stage of swallowing
-contraction of pharyngeal muscles with inhibition of respiration
-tongue action involved

Front 44

Pharyngeal stage:

Back 44

-second stage of swallowing
-involves epiglottis and vocal cords

Front 45

Esophageal stage:

Back 45

-3rd stage in swallowing
-consists of (upper) skeletal and (lower) smooth muscle
-peristalic wave occurs
-lower esophageal sphincter relaxes allowing bolus to enter stomach

Front 46

What cranial nerve is a stimulus for the mouth?

Back 46

Nerve V

Front 47

What cranial nerve is the swallowing center?

Back 47

Nerve IX (medulla)

Front 48

What cranial nerve stimulates oral and pharyngeals?

Back 48

Nerve X (vagus)

Front 49

4 Motor functions of the stomach:

Back 49

1. gastric filling and storage
2. emptying
3. regulation of gastric emptying
4. vomiting

Front 50

What pressure changes take place with emptying of the stomach?

Back 50

antral pressure exceeds duodenal pressure

Front 51

2 main functions of gastrin:

Back 51

1. enhances peristalsis
2. relaxes pylorus

Front 52

chyme:

Back 52

-highly acidic
-impedes gastric emptying

Front 53

vomiting:

Back 53

-sensory nerve endings in the pharynx, viscera and labyrinth
-process: vomiting center in medulla-glottis closes-trachea-LES relaxed-abd muscles contract-stomach empties

Front 54

2 functions of gastroenteric reflux:

Back 54

1. increases gastric motility
2. increases activity in the small intestine

Front 55

What is the main stimulus of the small intestine?

Back 55

stretch receptors

Front 56

What would cause a peristalic rush?

Back 56

intense irritation of the mucosa

Front 57

How is motility of the small intesting controlled?

Back 57

-thru the vagus nerve
-thru distention +/or irritation
-paralytic ileus (no peristalsis)

Front 58

cholecystokinin:

Back 58

-located in duodenum and jejunum
-stimulated by amino acids
-slows gastric emptying

Front 59

ileocecal sphincter:

Back 59

-normally closed
-interior of cecum and lower end of ascending colon
-regulates the flow of chyme into the bowels
-distention of cecum prevents reflux

Front 60

2 functions of the large intestine:

Back 60

1. absorption of water and electrolytes
2. storage of fecal mass

Front 61

Colonic movements of the large intestine:

Back 61

-inactive most of the time
-presence in proximal colon, haustral churning, contents to mucosa
-500cc of chyme enters each day (400cc is absorbed)

Front 62

secretin:

Back 62

-located in duodenum
-stimulated by acid pH or chyme entering duodenum
-decreases motility

Front 63

colonic movements:

Back 63

-inactive most of the time
-presence in proximal colon, haustral churning, contents to mucosa
-500cc chyme enters each day
(400cc)

Front 64

defecation:

Back 64

-distention of rectum
-from ileum to distal colon (18 hours)
-voluntary and involuntary

Front 65

gastric inhibitory peptide:

Back 65

-released from the intestinal mucosa in response to increased conc of glucose and fats
-inhibits gastric acid secretion, gastric motility and gastric emptying

Front 66

Histamine:

Back 66

-powerful stimulant to parietal cells
-released from antigen-antibody reaction
-H2 antagonists to reduce acid

Front 67

digestion of lipids:

Back 67

-mostly triglycerides but also phospholipids, cholesterol, vit A,D,E,K
-occurs in small intestine (emulsified by bile)

Front 68

pancreatic lipase:

Back 68

breaks down fatty acids and glycerol

Front 69

cholesterol:

Back 69

-esterase in pancreatic juice breaks down cholesterol and fatty acids to be absorbed

Front 70

Name 2 polysaccharides:

Back 70

maltose and dextrin

Front 71

pancreatic amylase:

Back 71

-produces maltase, sucrase and lactase

Front 72

cellulose:

Back 72

-not digested
-fiber
-gives proper bulk to the stool

Front 73

How much glucose is produced by carbohydrate digestion?

Back 73

80%

Front 74

digestion of proteins:

Back 74

-begins in stomach by pepsin secreted by chief cells

Front 75

pepsin:

Back 75

-secreted by chief cells in response to acid pH
-convert from pepsinogen
-inactivated when it enters the intestine by the alkaline pH

Front 76

pancreatic enzymes:

Back 76

-breaks down protein
-they are trypsin, chmotrypsin, carboxypeptidase, elastase

Front 77

distal ileum:

Back 77

-absorbs Vit B12 and bile salts
-contains bacteria and desquamated epith cells
-digestive secretions
-contain residues of food (cellulose)

Front 78

carbohydrates:

Back 78

-absorbed as monosaccharides
-polysacch and disacch are not absorbed due to high molecular weight

Front 79

lipids:

Back 79

-dissolved by bile salts for absorption (emulsification)
-absence of bile causes a reduction of fat absorption
-fat soluble vitamins are absorbed with fat
-monoglycerides are reduced to fatty acids and glycerol by lipase
-triglycerids + cholesterol + phospholipids --> chylomicrons --> into lacteals

Front 80

maturation:

Back 80

-initally gastric motility is not well coordinated so digestion of solid foods is inadequate
-at 12 weeks, peristalsis is good but slow so adequate absorption is needed