digestive Pt 3

Question 1

3 subdivisions of SI in order from proximal to distal

Answer 1

• duodenum
• jejunum
• ileum

Question 2

circular folds

Answer 2

permanent folds; bumps to slow/alter flow of chyme

Question 3

villi

Answer 3

finger like projections of mucosa

Question 4

brush border

Answer 4

give a fuzzy appearance
- brush border enzymes complete final carbohydrate + protein digestion

Question 5

5 types of cells found in the villi/crypts

Answer 5

1. enterocytes
2. goblet cells
3. enteroendocrine
4. paneth cels
5. stem cells

Question 6

entercytes

Answer 6

make up the bulk of the epithelium
- in the villi, absorb nutrients and electrolytes
- in the crypts, produce Intestinal juice

Question 7

goblet cells

Answer 7

secrete mucus in the villi and crypts

Question 8

enteroendocrine

Answer 8

source of enterogastrones - hormones that inhibit secretions

Question 9

paneth cells

Answer 9

secretory cells found deep in the crypts - secrete antimicrobial agents

Question 10

stem cells

Answer 10

continuously divide to produce other cell types - epithelium is renewed every 2-4 days

Question 11

Peyers patches

Answer 11

aggregate lymphoid nodules, located in the lamina propria

Question 12

duodenal gland

Answer 12

secrete alkaline mucus to neutralize acidic chyme and prevent duodenal ulcers

Question 13

Intestinal juice

Answer 13

• 1-2L are secreted daily in response to distension or irritation of the mucosa
• production stimulated by acidic chyme
• slightly alkaline, isotonic with blood plasma
• largely water + mucus from the duodenal glands and goblet cells

Question 14

why is the slow pace of chyme entering SI crucial

Answer 14

• chyme entering duodenum is hypertonic - to avoid water loss from blood, chyme entry must be slow
• acidic chyme must be neutralized
• takes time for chyme to be mixed with bile and pancreatic juice

Question 15

ileocecal valve

Answer 15

typically closed; relaxes to admit chyme into the LI; closes to prevent regurgitation

Question 16

gastroileal reflex

Answer 16

long neural reflex triggered by stomach activity - force of segmentation is increased in the ileum and ilececal valve relaxes

Question 17

Be prepared to label the main pancreatic duct, the hepatopancreatic ampulla, and the major duodenal papilla. .

Question 18

functions of LI

Answer 18

• reabsorb lost of the remaining water from indigestible food residue
• temporarily stores residue
• absorb metabolites produces by resident bacteria
• eliminate residue from the body as semisolid feces

Question 19

teniae coli

Answer 19

3 bands of longitudinal smooth muscle in the muscularis

Question 20

haustra

Answer 20

pocket like sacs caused by the muscular tone of teniae coli

Question 21

Be prepared to label the subdivisions and major landmarks of the LI.

Question 22

appendix

Answer 22

contains masses of lymphoid tissue
- part of MALT
- storehouse for bacteria, capable of recolonizing the gut when necessary
- susceptible to blockages because of twisted shape

Question 23

which of the anal sphincters are under voluntary control

Answer 23

external anal sphincter

Question 24

what type of vitamins are produced in the LI

Answer 24

B and K
K (needed by liver to produce clotting factors)

Question 25

gut bacteria can influence what

Answer 25

• body weight
• susceptibility to diseases
• allergies
• moods/mental health

Question 26

haustral contractions

Answer 26

primary contractions of the colon; slow, segmenting movements primarily in the ascending and transverse colon; haustra sequentially contract in response to distention

Question 27

gastrocolic reflex

Answer 27

initiated by the presence of food in the stomach; causes mass movements; slow, powerful peristaltic waves that are activated 3-4 times/day

Question 28

diverticula

Answer 28

herniations of mucosa through the colon’s walls

Question 29

diarrhea

Answer 29

watery, loose stools; LI does not have time to absorb remaining water
- causes: irritation of the colon by bacteria, jostling of digestive viscera
- prolonged diarrhea may result in dehydration and electrolytes imbalances

Question 30

constipation

Answer 30

food residue remains in the colon for extended periods of time; too much water is absorbed
- stool becomes hard and difficult to pass
- causes: insufficient fiber and/or fluid in the diet, improper bowel habits, lack of exercise, or laxative abuse