chapter 24 part 2 Flashcards

1
Q

chief cells

  • definition
  • function
A
  • cells of the gastric gland

- secrete pepsinogen

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2
Q

pepsinogen

  • inactive or active enzyme
  • where is it secreted into
  • formula
A
  • inactive
  • into stomach lumen
  • pepsinogen -HCL-> pepsin
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3
Q

pepsin

  • active or inactive enzyme
  • function
A
  • active

- breaks proteins into short fragments

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4
Q

G cells

  • aka
  • function
A
  • pylorus or enteroendocrine cells

- produce gastrin hormone

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5
Q

gastrin

A

increase gastric motility and gastric juice secretion

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6
Q

regulation of gastric secretions

-3 phases

A
  1. cephalic
  2. gastric
  3. intestinal
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7
Q

cephalic phase

  • 4 things
  • what does it do
A
  • seeing, tasting, thinking about food, and food in the mouth
  • increase gastric juice secretions which is controlled by PNS
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8
Q

gastric phase

  • definition
  • what does this phase do
  • 3 mechanisms
A
  • food enters the stomach
  • increase gastric juice secretion
    1. neural response
      1. hormonal response
      2. local response
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9
Q

neural response of the gastric phase

A

stretch receptors and chemoreceptors

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10
Q

hormonal response of the gastric phase

A

increase gastrin release

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11
Q

local response of the gastric phase

A

release of histamine in the lamina propria

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12
Q

intestinal phase

  • definition
  • what does this phase do
  • 2 mechanisms
  • what is this controlled by
A
  • food enters the small intestine
  • decreases gastric juice production
  • neural and hormonal
  • the duodenum in response to the arrival of chyme
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13
Q

neural response of the intestinal phase

A

enterogastric reflex

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14
Q

hormonal response of the intestinal phase

-contains

A
  1. secretin
  2. gastro inhibitory
  3. cholecystokinin
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15
Q

what do accessory glands do

A

empty secretions into the small intestine

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16
Q

liver

  • what does it secrete
  • 4 things
A
  • bile
    1. L and R hepatic ducts merge to form the common hepatic duct
      1. common hepatic duct and cystic duct merge to form the common bile duct
      2. pancreatic duct and common bile duct merge at the duodenal ampulla
      3. bile and pancreatic juices enter the duodenum at the duodenal papilla
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17
Q

bile

  • contents
  • 2 functions
  • how much is produced/day
A
  • H2O, Ions, bilirubin and bile salts (derivative of cholesterol)
    1. emulsify fat
      1. aid in fat absorption
  • 1 L
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18
Q

emulsify fats

A

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

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19
Q

gallbladder

-2 functions

A

stores bile (40-70ml) and concentrates bile

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20
Q

chyme in the duodenum

-what does the duodenum secrete

A

cholecystokinin

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21
Q

cholecystokinin

-2 functions

A
  1. promotes contractions of the gallbladder

2. opens hematopancreatic sphincter

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22
Q

pancreas

  • 2 glands
  • composition of pancreatic juice
A
  • endocrine gland and exocrine gland

- water, bicarbonate and phosphate buffers, enzymes

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23
Q

endocrine gland of the pancreas

  • percent
  • contains
  • function
A
  • 1%
  • pancreatic islets
  • secretes insulin and glucagon
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24
Q

exocrine gland of the pancreas

  • percent
  • contains
A
  • ~99%

- pancreatic acini

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25
Q

pancreatic acini

  • function
  • how much is produced per day
A
  • pancreatic juice

- 1L

26
Q

bicarbonate and phosphate buffers are important for

A

the dilution and buffering of acids in chyme

27
Q

enzymes in the pancreatic juice

A
  1. pancreatic alpha amylase
  2. pancreatic lipase
  3. nucleases
  4. proteolytic enzymes
28
Q

pancreatic alpha amylase

  • identical to what
  • functions
A
  • salivary amylase

- breaks down starches and produces di and tri saccharrides

29
Q

nucleases

-2 functions

A
  1. breakdown nucleic acids (RNA and DNA)

2. produces nitrogenous bases and simple sugars

30
Q

proteolytic enzymes

  • definition
  • secreted as inactive or active forms
A

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

31
Q

inactive proenzymes are activated when

A

after reaching the small intestine

32
Q

Proenzyme: trypsinogen

  • active enzyme
  • enzyme responsible for conversion
  • function of active enzyme
A
  • trypsin
  • enteropeptidase
  • converts proenzyme into active
33
Q

enteropeptidase

A

produced by intestinal glands of duodenum

34
Q

Proenzyme: Chymotrysinogen

  • active enzyme
  • enzyme responsible for conversion
  • function of active enzyme
A
  • chymotrypsin
  • trypsin
  • breakdown protein and polypeptides
35
Q

Proenzyme: procarboxypeptide

  • active enzyme
  • enzyme responsible for conversion
  • function of active enzyme
A
  • carboxypeptidase
  • trypsin
  • breaks down proteins and poly peptides
36
Q

Proenzyme: proelastase

  • active enzyme
  • enzyme responsible for conversion
  • function of active enzyme
A
  • elastase
  • trypsin
  • breaks down elastin
37
Q

regulation of pancreatic secretion

  • stimulus
  • 3 hormones released
A
  • hormones released from duodenum when chyme enters

- secretin, cholecystokinin and gastric inhibitory peptide

38
Q

secretin

-2 functions

A
  1. stimulates secretion of watery buffer portion of pancreatic juice
  2. help to neutralize the pH of chyme
39
Q

cholecystokinin

2 functions

A
  1. stimulates production of pancreatic enzymes

2. causes relaxation of the hepatopancreatic sphincter

40
Q

gastric inhibitory peptide

  • when is it released
  • function
A
  • when chyme containing large quantities of glucose arrives

- stimulates release of insulin by pancreas

41
Q

the small intestine

-contains

A

brush border enzymes

42
Q

brush border enzymes

  • definition
  • 2 types
A
  • enzymes made by columnar epithelial cells of the villi
    1. protein digesting enzymes
      1. carbohydrate digesting enzymes
43
Q

protein digesting enzymes

-2 types

A
  1. enteropeptidase

2. dipeptidase/peptidase

44
Q

enteropeptidase

A

targets proenzyme trypsinogen and coverts it to trypsin

45
Q

dipeptidase/peptidase

A

targets di and tripeptides and breaks them into single AA

46
Q

carbohydrate digesting enzymes

-breaks down 3 carbs

A
  1. sucrase
  2. maltase
  3. lactase
47
Q

sucrase broken down into

  • maltase
  • lactase
A
  • glucose and fructose
  • glucose and glucose
  • glucose and galactose
48
Q

Absorption

  • where?
  • 3 modifications
A
  • stomach, small and large intestine
    1. Plica circulares
      1. villi
      2. microvilli
49
Q

absorption in

  • stomach
  • small intestine
  • large intestine
A

drugs like alc and asprin

  • nutrients from food and water
  • water and ions
50
Q

plica circulares

  • definition
  • function
A
  • series of folds found in the small intestine; permanent features
  • increases surface area for absorption
51
Q

villi

  • definition
  • function
A
  • fingerlike projections

- increases surface for absorption

52
Q

microvilli

  • definition
  • function
A
  • on columnar epithelial cells found covering the villi

- increases surface for absorption

53
Q

movement of water depends on

A

osmotic gradients

54
Q

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
A
  • ~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
Q

Absorption: blood

  • what does the lamina propria of the villi contain
  • capillaries carry absorbed nutrients to the
A
  • capillary bed

- hepatic portal circulation

56
Q

hepatic portal circulation

-nutrients are delivered to the ___ for ___

A

liver for storage, metabolic conversion or excretion

57
Q

Lymphatics:lacteals

  • definition
  • function
  • ex
  • returned to venous system through
A
  • 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
Q

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

A

in the mucosa of the sm intestine

59
Q

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

A
  • monosacchrides (glucose, fructose and galactose)
  • enter through facilitated diffusion and co-transport
  • enters capillaries by facilitated diffusion
60
Q

co-transport

A

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

61
Q

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

A
  • AA
  • enter through facilitated diffusion and co transport
  • enter capillaries by facilitated diffusion and co transport
62
Q

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

A
  • 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