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Flashcards in GI System Deck (129):
1

What the body can process

Amino acids, monosaccharides, and fatty acids

2

What kind of cells line digestive mucosa to lubricate, digest, etc

Epithelial

3

What regulates GI secretions and motility

Intrinsic nerve plexus

4

What can facilitate digestion and absorption

Fluid volumes and pH changes (enzyme function)

5

PH of chyme in jejunum

7

6

Small intestine roles: 5

Enzymatic digestion, absorbs h20, organic substrates, vitamins and ions, host defense

7

Large intestine roles 3

Resorts water and electrolytes, host defense, dehydration/compaction for elimination

8

Pancreas roles 2

Secretes buffers and digestive enzymes, secretes hormones to regulate digestion

9

Endocrine is into what

Blood

10

Exocrine is into what

Gland or duct

11

Serosa: 2 layers and it is what

CT layer and peritoneum, innervated

12

2 layers of intramural plexus and where it is

Myenteric plexus and submucosal plexus. On submucosa and muscular layers

13

How digestive glands empty products into lumen of gi tract

Ducts

14

What gives nutrients from blood to GI tract

Aorta

15

What carriers nutrients to liver from organs

Portal vein

16

Myenteric plexus outside of what

Circular muscle layer

17

What is outside of submucosa

Submucosal plexus

18

Chyme is what

Food, acids, enzymes, saliva

19

Gastric gland cells

Mucous neck cells, parietal cells, chief cells, endocrine cells

20

What controls myenteric plexus and submucosal plexus, what are their roles

Both- enteric
Myenteric=- muscle, movement
Submucosal- secretions

21

What PNS innervates in GI

Vagal to transverse colon, pelvic nerves to anus

22

What acts on the enteric NS

Lumenal chemo, mechanoreceptors, and osmoreceptors

23

Where parts of chyme go after entering duodenum

Simple sugars, fats, and amino acids go to lacteal. Simple sugars and AA absorbed into blood capillaries of villi. Fat enters lacteal to be processed in liver

24

Lactose, maltose, sucrose components

Lactose is glucose and galactose
Maltose is 2 glucose
Sucrose is glucose and fructose

25

Process of enzymes breaking down carbs. 4 main processes in order

1. Starch broken down my salivary amylase in mouth to oligo/dextrin
2. Pancreatic amylase breaks them down to lactose, maltose, sucrose
3. Brush border enzymes in SI break disaccharides down to mono
4. Mono absorbed by capillaries in vile and trans to liver by portal vein

26

Steps of protein absorption 4

1. Pepsin in hcl breaks proteins- proteoses and peptones
2. Pancreatic enzymes break those down to dipeptides and smaller peptides in SI
3. Brush border enzymes in SI break down to AA
4. Abs by capillaries in villi, trans to liver by portal vein

27

What cells break things down in stomach

Chief and parietal cells

28

Digestion of fat steps

Unemulsified fats broken down in SI by bile acids, etc in SI. Pancreatic lipases also act here. Monoglycerides and FA go to lacteals in villi and go to liver. Glycerol and FA go directly into villi and portal vein like carbs and AA

29

2 different routes of fat from SI

MG and FA- lacteal to liver
Glycerol and FA- directly into villi to liver

30

Oblique muscle layer role in stomach

Aids in grinding food

31

Receptive relaxation: mediated by what, what causes it to start

Vagally mediated
Pushing on the stomach causes release of vasoactive intestinal peptide (VIP)

32

MMC role, under what control

Mixes and propulses food
Enteric

33

What vagotomy does to stomach as food enters

Receptive relaxation not stimulated, pressure increases as volume increases (doesnt increase volume to accommodate more food)

34

Emptying time/order of oleate, acid, and saline meals in stomach

Salt fastest, then acid, then oleate.
FATS TAKE LONGEST TO DIGEST IN STOMACH

35

MMC: when its activated. What activates it. Which nervous system control

Fasting state
Motilin
Enteric control, NOT vagal

36

What slow waves due, what they are

Basic electrical rhythm, set timing for when action potentials occur

37

What causes depolarization in GI

Stretch, ans, pns, gastrin*, serotonin*, sub P*
**hormones

38

What causes hyperpolarization in GI

NE, SNS, VIP, NO

39

The __ and __ stim of sensory neurons works through __ and __ motor neurons to elicit motility

Mechanical, chemical
Excitatory, inhibitory

40

What stimulates relaxation in peristalsis, what stimulates contraction

Relax- VIP
Contract- cholinergic motor neurons and tachykinin

41

Peristalsis under what kind of control

Vagal and extrinsic

42

What leads to receptive relaxation

MMC, propulsion by peristalsis and segmentation

43

Segmentation is controlled by what

Intrinsic/enteric nerve control

44

What stimulates gallbladder contraction

Vagal stimulation relaxes the sphincter of oddi- into duodenum. Hormone CCK+vagal stim stimulates gallbladder contraction

45

What movements are in 3 parts of LI

Peristalsis
Segmental propulsion, taneia coli contract
Mass movements at end

46

Mass movements; assoc with 3

Eating, PNS and hormonal control (gastrin and CCK)

47

Haustra formed by what

Contraction of taneia coli

48

Defecation through what

IAS reflex, voluntary relaxation EAS, valsalva maneuver

49

Reflexes top to bottom 7

Gastroileal
Gastrocolic
Ileogastric
Enteroenteric/intenstinointestinal
Colonocolonic
Cecoileal
Rectosphincteric (defecation reflex)

50

Secretions in mouth

Saliva, lingual lipase, salivary amylase

51

Esophagus secretions

Electrolytes and mucus

52

Stomach secretions

Hcl, IF, pepsinogen, gastric lipase, mucus, gastrin, somatostatin, histamine

53

Liver and gallbladder secretions

Bile and buffers (electrolytes)

54

SI secretions

Buffers (mucus and electrolytes), brush border disacharidases and peptidases, enterokinases, (somatostatin, secretin, gastrin, cck, vip, motilin into blood)

55

Stomach factors 6

Histamine, pepsinogen, gastric lipase, somatostatin, gastrin, mucus

56

Salivary gland output from where, relative %

70% most from submaxillary glands
25% parotid gland (amylase)
5% sublingual gland

57

Acinar cells do what

Make digestive enzymes and secretion of what ends up in saliva

58

Myoepithelial cells do what

Contract and lead saliva into mouth

59

How blood vessels work w salivary formation

Feed cells, provide filtrate for water formation in saliva

60

Saliva contains what 4

Amylase, na, k, cl, hco3

61

Hormone impact on saliva: adh, aldosterone

Adh inc water absorption, concentrates saliva
Aldosterone increases k secretion into and na reabsorption out of saliva

62

Pth does what to saliva

Calcium absorption

63

Factors that affect salivary secretion other than hormones and nervous control 7

Nausea, esophageal distension, sleep, dehydration, drugs, age, food composition

64

Salivary acinus nervous control

ANS (PNS Ach and VIP, SNS NE)
Central (afferrent and efferent to salivary nucleus)

65

Saliva is always what

Hypotonic to plasma, but similar composition

66

Final tonicity of saliva dependent on what, what effects it

Flow through ducts. Rate increases, osmolality increases because less electrolyte reabsorption

67

What is primarily reabsorbed from saliva into ducts

HCO 3

68

What causes gallbladder contraction

CCK and vagal

69

Order of GI tissue top to bottom

Mucosa: epithelial cells, secretions to lube/protect
Submucosa: glands and ducts, exocrine
Muscular layers
Serosa: CT and peritoneum

70

Layers of mucosa: 1 and 2

Surface mucous cells- release mucus, lube and protect mucosa
Mucous neck cells- same as above

71

Layers of mucosa: 3 and 4

Parietal cells- make HCL and IF, digest food, kill bacteria, convert pepsinogen, b12 absorption

Chief cells- release pepsinogen and gastric lipase, digest proteins and fats

72

Layers of mucosa: 5

Endocrine cells-
D cells- somatostatin (inhibits hcl and gastrin release)
G cells- gastrin (stim parietal cells, gastrin, IF, R protein)
ECL- stim HCL release

73

HCL jobs 3

Digests food, kills bacteria, converts pepsinogen to pepsin's

74

IF: only secretion that is what, what it does

Only indispensable secretion
B12 absorption in duodenum

75

Pepsinogens

Cleaved to pepsin in acidic enviro

76

Gastrin: stim 2, decreases what

Gastric motility and hcl secretion, decreases gastric emptying

77

Somatostatin does what

Inhibits HCL secretion

78

Histamine does what

Stimulates HCL secretion

79

R protein does what

Protects b12 from degradation until duodenum. There its cleaved by trypsin and IF digests b12

80

Grehlin: does what

When fasting acts on hypothalamus to stimulate hunger, opposes satiety of leptin/peptide yy

81

Mucinase

Disrupts bicarb and mucus layer, leads to ulcers

82

Parietal cell releases HCL. __ gets into lumen. Starts as CO2 and __. Becomes __ and __. H ion is exchanged to lumen via what. __ ion uses __ exchanger to get into cell and maintain neutrality

H. Ca. Bicarb and acid
H/K ATPase
Bicarb

83

3 things that stimulate HCL secretion

Ach, gastrin, histamine

84

What inhibits HCL secretion 4

Secretin (g cells)
Somatostatin (parietal and g cells)
GIP (parietal cells)
Prostaglandins (ecl and G cells)

85

Salivary amylase: breaks starches down into __ or __

Dextrin or oligosaccharides

86

Pancreatic amylase: breaks __ or __ into __, __, or __

Dextrin or oligosaccharides to lactose, maltose, sucrose

87

Brush border enzymes: in __ __. Break __, __, or __ into __, __, and __

SI
Lactose/maltose/sucrose into glucose, galactose, fructose

88

Proteins broken down by what in stomach into __ and __

Pepsin
Proteoses and peptones

89

In stomach, proteoses and peptones are broken down by what into what

Pancreatic enzymes
Small polypeptides

90

Small polypeptides are broken down by what into what in SI

Brush border enzymes, amino acids

91

Unemulsified fats: where digestion begins, addition of what

SI, emulsifying agents or pancreatic lipases

92

When broken down in SI unemulsified fats become what or what and path of absorption

MG and FA - absorbed into lacteals to go to liver
Glycerol and FA- absorbed into capillaries of villi to go to liver

93

Receptive relaxation: mediated by what, release of what

Vagal, VIP
Pressure on stomach causes muscles to relax

94

Spikes on top of slow waves caused by 3

Stretch, Ach, PNS

95

Peristalsis in SI under what kind of frontal

Enteric, non CNS

96

SI peristalsis
Contraction caused by __ and __ motor neurons
Relaxation by __ motor neuron

Tachykinin and cholinergic
VIP

97

LI does NOT have what

VILLI

98

Saliva: __ to plasma but has more what. Contains what

Hypotonic, more bicarb
Coag factors, WBC, IgA

99

Acinar cells do what

Make digestive enzymes and saliva

100

Myoepithelial cells do what

Empty acinar cell content into mouth by alpha adrenergic fibers

101

___ inhibits saliva production
___ increases K in saliva
Slower flow leads to what in tonicity of saliva

ADH
Aldosterone
More electrolytes reabsorbed, less tonicity

102

Endocrine secretions 2

Gastrin into stomach and intestine- HCL
CCK- intestine

103

Paracrine secretions 2, where

Somatostatin and histamine into intestine

104

Vagus can stim release of what 2 secretions

ACH and GRP

105

What happens in cephalic phase of gastric secretion

Anticipation chemo and mechanoreceptors on tongue/buccal/nasal mucosa, vagal fox, gastrin/acid/enzymes

106

What happens in gastric phase of secretion

Vagal effects, gastrin, acid, enzyme, pH change

107

What happens in intestinal phase of gastric secretion

Mucosal secretions (mucus, hormones, enzymes) and sec from pancreas, liver, gallbladder from hepatic duct to sphincter of oddi

108

When food enters duodenum, ___ is released. It decreases __ secretion, purpose

Secretin, gastrin
Less acidic to protect mucosa

109

Endocrine cells in SI release what

Gastrin, cck, secretin, gip, motilin, serotonin

110

Brunners glands: secretes what where
Stim by what

Mucus and proteases at duodenum before oddi
Pns, vagus, secretin

111

Cholesterol is absorbed by __ to __ system to __ duct to __ vein

Lacteal, lymph, thoracic, subclavian

112

High fat diet more likely what will be released

Cck

113

Pancreas
Endocrine functions: 3
Exocrine functions: 2

Somatostatin, insulin, glucagon

Proteases and electrolytes

114

In acinar cells: what kind of exchange occurs

Electrolyte exchange throughout duct

115

What are trypsinogen and chymotrypsin

Tryp- activated to trypsin in duodenum by enterokinases
Chym- activated by trypsin

116

Ileum secretes __ and __

H and bicarb, bicarb as buffer in exchange for chloride

117

What increases SI surface area

Villi and microvilli

118

Fructose: goes in apical side through what, basolateral side through what

GLUT5, GLUT2

119

Glucose and galactose enter cell by __ transporter, and __
___ pump on basolateral side function

Na/X transporter (piggy back na gradient)
SGLT1
Na/k, transports Na out against gradient so Na and MG can come in on apical side

120

Protein breakdown in stomach

HCL stim secretion of pepsinogen, cleaved to pepsin in acid which breaks down proteins

121

Protein breakdown in lancrease

Proteases secreted as zymogens through pancreatic duct into duodenum. Fire extinguisher for trypsin. Breaks down into bases

122

Protein breakdown in SI by what

Pancreatic proteases activated by intestinal enterokinases, maintains optimal pH

123

Lipid digestion in mouth

Lingual lipase cleaves TG to FA and DG

124

Lipid digestion in stomach

Gastric lipase cleaves TG to FA and DG

125

Lipid digestion in SI

Peptides and fats in duodenum initiate CCK release and gallbladder contraction. Panc enzymes thru oddi. Panc lipase converts FA and MG

126

3 fats that need to be broken down, and what they're broken down into

TG: dg and fa to mg
Cholesterol esters- cholesterol and acid
Phospholipids- further

127

Pancreatic lipase is inactive in presence of what. CCK does what

Inactive in presence of bile salts
CCK stim both bile release and panc lipase

128

Product of emulsion is a __. Crosses __ __ layer. To brush border membrane where fats released and taken to __. Once there repackaged into __ and enter __.

Micelle. Unstirred aqueous. Cytoplasm.
Chylomicron. Lacteal (if not goes to blood)

129

Bile absorption occurs where

Terminal ileum