chapter 24 part 2 Flashcards Preview

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Flashcards in chapter 24 part 2 Deck (62):
1

chief cells
-definition
-function

-cells of the gastric gland
-secrete pepsinogen

2

pepsinogen
-inactive or active enzyme
-where is it secreted into
-formula

-inactive
-into stomach lumen
-pepsinogen -HCL-> pepsin

3

pepsin
-active or inactive enzyme
-function

-active
-breaks proteins into short fragments

4

G cells
-aka
-function

-pylorus or enteroendocrine cells
-produce gastrin hormone

5

gastrin

increase gastric motility and gastric juice secretion

6

regulation of gastric secretions
-3 phases

1. cephalic
2. gastric
3. intestinal

7

cephalic phase
-4 things
-what does it do

-seeing, tasting, thinking about food, and food in the mouth
-increase gastric juice secretions which is controlled by PNS

8

gastric phase
-definition
-what does this phase do
-3 mechanisms

-food enters the stomach
-increase gastric juice secretion
-1. neural response
2. hormonal response
3. local response

9

neural response of the gastric phase

stretch receptors and chemoreceptors

10

hormonal response of the gastric phase

increase gastrin release

11

local response of the gastric phase

release of histamine in the lamina propria

12

intestinal phase
-definition
-what does this phase do
-2 mechanisms
-what is this controlled by

-food enters the small intestine
-decreases gastric juice production
-neural and hormonal
-the duodenum in response to the arrival of chyme

13

neural response of the intestinal phase

enterogastric reflex

14

hormonal response of the intestinal phase
-contains

1. secretin
2. gastro inhibitory
3. cholecystokinin

15

what do accessory glands do

empty secretions into the small intestine

16

liver
-what does it secrete
-4 things

-bile
-1. L and R hepatic ducts merge to form the common hepatic duct
2. common hepatic duct and cystic duct merge to form the common bile duct
3.pancreatic duct and common bile duct merge at the duodenal ampulla
4. bile and pancreatic juices enter the duodenum at the duodenal papilla

17

bile
-contents
-2 functions
-how much is produced/day

-H2O, Ions, bilirubin and bile salts (derivative of cholesterol)
-1. emulsify fat
2. aid in fat absorption
-1 L

18

emulsify fats

conversion of a large fat blob into smaller fat droplets making it easier for chemical digestion

19

gallbladder
-2 functions

stores bile (40-70ml) and concentrates bile

20

chyme in the duodenum
-what does the duodenum secrete

cholecystokinin

21

cholecystokinin
-2 functions

1. promotes contractions of the gallbladder
2. opens hematopancreatic sphincter

22

pancreas
-2 glands
-composition of pancreatic juice

-endocrine gland and exocrine gland
-water, bicarbonate and phosphate buffers, enzymes

23

endocrine gland of the pancreas
-percent
-contains
-function

-1%
-pancreatic islets
-secretes insulin and glucagon

24

exocrine gland of the pancreas
-percent
-contains

-~99%
-pancreatic acini

25

pancreatic acini
-function
-how much is produced per day

-pancreatic juice
-1L

26

bicarbonate and phosphate buffers are important for

the dilution and buffering of acids in chyme

27

enzymes in the pancreatic juice

1. pancreatic alpha amylase
2. pancreatic lipase
3. nucleases
4. proteolytic enzymes

28

pancreatic alpha amylase
-identical to what
-functions

-salivary amylase
-breaks down starches and produces di and tri saccharrides

29

nucleases
-2 functions

1. breakdown nucleic acids (RNA and DNA)
2. produces nitrogenous bases and simple sugars

30

proteolytic enzymes
-definition
-secreted as inactive or active forms

70% of enzymes produced by pancreas breakdown proteins to form short chain peptides
-inactive proenzymes

31

inactive proenzymes are activated when

after reaching the small intestine

32

Proenzyme: trypsinogen
-active enzyme
-enzyme responsible for conversion
-function of active enzyme

-trypsin
-enteropeptidase
-converts proenzyme into active

33

enteropeptidase

produced by intestinal glands of duodenum

34

Proenzyme: Chymotrysinogen
-active enzyme
-enzyme responsible for conversion
-function of active enzyme

-chymotrypsin
-trypsin
-breakdown protein and polypeptides

35

Proenzyme: procarboxypeptide
-active enzyme
-enzyme responsible for conversion
-function of active enzyme

-carboxypeptidase
-trypsin
-breaks down proteins and poly peptides

36

Proenzyme: proelastase
-active enzyme
-enzyme responsible for conversion
-function of active enzyme

-elastase
-trypsin
-breaks down elastin

37

regulation of pancreatic secretion
-stimulus
-3 hormones released

-hormones released from duodenum when chyme enters
-secretin, cholecystokinin and gastric inhibitory peptide

38

secretin
-2 functions

1. stimulates secretion of watery buffer portion of pancreatic juice
2. help to neutralize the pH of chyme

39

cholecystokinin
2 functions

1. stimulates production of pancreatic enzymes
2. causes relaxation of the hepatopancreatic sphincter

40

gastric inhibitory peptide
-when is it released
-function

-when chyme containing large quantities of glucose arrives
-stimulates release of insulin by pancreas

41

the small intestine
-contains

brush border enzymes

42

brush border enzymes
-definition
-2 types

-enzymes made by columnar epithelial cells of the villi
-1. protein digesting enzymes
2. carbohydrate digesting enzymes

43

protein digesting enzymes
-2 types

1. enteropeptidase
2. dipeptidase/peptidase

44

enteropeptidase

targets proenzyme trypsinogen and coverts it to trypsin

45

dipeptidase/peptidase

targets di and tripeptides and breaks them into single AA

46

carbohydrate digesting enzymes
-breaks down 3 carbs

1. sucrase
2. maltase
3. lactase

47

sucrase broken down into
-maltase
-lactase

-glucose and fructose
-glucose and glucose
-glucose and galactose

48

Absorption
-where?
-3 modifications

-stomach, small and large intestine
-1. Plica circulares
2. villi
3. microvilli

49

absorption in
-stomach
-small intestine
-large intestine

drugs like alc and asprin
-nutrients from food and water
-water and ions

50

plica circulares
-definition
-function

-series of folds found in the small intestine; permanent features
-increases surface area for absorption

51

villi
-definition
-function

-fingerlike projections
-increases surface for absorption

52

microvilli
-definition
-function

-on columnar epithelial cells found covering the villi
-increases surface for absorption

53

movement of water depends on

osmotic gradients

54

absorption of water
-ingest
-saliva adds how many ml
-gastric secretions
-liver
-pancreas
-intestinal secretions
-sm intestine reabsorbs
-colonic mucous secretions
-some H2O reabsorption
-___ ml of H2O in feces

- ~2000 ml
- ~1500 ml
- ~1500 ml
- 1000 ml of bile
- 1000 ml of pancreatic juice
- 2000 ml
- (92%)
- ~200 ml
- (~6-7%)
- 150 ml

55

Absorption: blood
-what does the lamina propria of the villi contain
-capillaries carry absorbed nutrients to the

-capillary bed
-hepatic portal circulation

56

hepatic portal circulation
-nutrients are delivered to the ___ for ___

liver for storage, metabolic conversion or excretion

57

Lymphatics:lacteals
-definition
-function
-ex
-returned to venous system through

-lymphatic vessel present in lamina propria of villi
-transport materials that cannot enter blood vessels; usually things that are too large to enter capillaries
-lipoproteins (lipid and protein combos)
-thoracic duct

58

where does the absorption of carbs, proteins and lipids take place

in the mucosa of the sm intestine

59

absorption: carbs
-lumen
-epithelial cell of the villus
-blood stream

-monosacchrides (glucose, fructose and galactose)
-enter through facilitated diffusion and co-transport
-enters capillaries by facilitated diffusion

60

co-transport

requires a carrier protein and an ion to move in the same direction (usually Na+)

61

absorption: proteins
-lumen
-epithelial cell of the villus
-blood stream

-AA
-enter through facilitated diffusion and co transport
-enter capillaries by facilitated diffusion and co transport

62

absorption: lipid
-lumen
-epithelial cell of the villus
-bloodstream

-large lipid droplets -bile-> small lipid droplets -pancreatic lipase-> FA and glycerol
-enters by diffusion; glycerol and FA recombine in the cell; become coated with proteins = chylomicrons; too large to enter capillaries
-enter lacteals through exocytosis; re enter venous system through thoracic duct