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