GI System Flashcards
1
Q
What the body can process
A
Amino acids, monosaccharides, and fatty acids
2
Q
What kind of cells line digestive mucosa to lubricate, digest, etc
A
Epithelial
3
Q
What regulates GI secretions and motility
A
Intrinsic nerve plexus
4
Q
What can facilitate digestion and absorption
A
Fluid volumes and pH changes (enzyme function)
5
Q
PH of chyme in jejunum
A
7
6
Q
Small intestine roles: 5
A
Enzymatic digestion, absorbs h20, organic substrates, vitamins and ions, host defense
7
Q
Large intestine roles 3
A
Resorts water and electrolytes, host defense, dehydration/compaction for elimination
8
Q
Pancreas roles 2
A
Secretes buffers and digestive enzymes, secretes hormones to regulate digestion
9
Q
Endocrine is into what
A
Blood
10
Q
Exocrine is into what
A
Gland or duct
11
Q
Serosa: 2 layers and it is what
A
CT layer and peritoneum, innervated
12
Q
2 layers of intramural plexus and where it is
A
Myenteric plexus and submucosal plexus. On submucosa and muscular layers
13
Q
How digestive glands empty products into lumen of gi tract
A
Ducts
14
Q
What gives nutrients from blood to GI tract
A
Aorta
15
Q
What carriers nutrients to liver from organs
A
Portal vein
16
Q
Myenteric plexus outside of what
A
Circular muscle layer
17
Q
What is outside of submucosa
A
Submucosal plexus
18
Q
Chyme is what
A
Food, acids, enzymes, saliva
19
Q
Gastric gland cells
A
Mucous neck cells, parietal cells, chief cells, endocrine cells
20
Q
What controls myenteric plexus and submucosal plexus, what are their roles
A
Both- enteric
Myenteric=- muscle, movement
Submucosal- secretions
21
Q
What PNS innervates in GI
A
Vagal to transverse colon, pelvic nerves to anus
22
Q
What acts on the enteric NS
A
Lumenal chemo, mechanoreceptors, and osmoreceptors
23
Q
Where parts of chyme go after entering duodenum
A
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
Q
Lactose, maltose, sucrose components
A
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
