Phys review Flashcards
(83 cards)
1
Q
mucosa layers
A
epithelium
lamina propria
muscularis mucosa
2
Q
lamina propria
A
layer of CT which contains glands, hormone-containing cells, lymph nodes, and capillaries
3
Q
submucosa
A
a layer of CT that contains glands, large vessels, and lymphatics
outermost region has Meissner’s plexus
4
Q
Meissner’s plexus
A
in submucosa
part of ENS and involved in secretory activity
5
Q
musclarisexterna
A
inner layer of circular mm
outer layer of longitudinal mm
myenteric nn plexus btwn layers
6
Q
serosa
A
outermost layer of GI tract
consists of CT and layer of epi
w/in this layer autonomic nn run and synpase of target cells and ENS plexuses
7
Q
NE
A
sympathetic
decreases motility and secretion
increases constriction of sphincter
8
Q
ACh
A
increased motility and secretions
9
Q
VIP
A
decreased constriction of sphincter
10
Q
GRP
A
increases gastrin
11
Q
secretin
A
from S cells lining duodenum
stimulated by acid entering duodenum
inhibits stomach motility and secretion
stimulates HCO3 secretion from pancreas
12
Q
CCK
A
from cells lining duodenum
stimulated by fat and aa entering duodenum
inhibits emptying
stimulates pancreatic enzyme secretion
causing contraction of gallbladder and relaxation of sphincter
13
Q
GIP
A
from duodenum
stimualted by fat, CHO, aa
inhibits stomach motility and secretion
14
Q
events of swallowing
A
relaxation of UES primary peristalitic wave relaxation of LES via VIP relaxation of proximal stomach if primary perstaltic wave not sufficient local distention will initiate a second
15
Q
achalasia
A
LES fails to relax due to abnormalities of ENS
primary pertalsis in esophgeal body poor
pressure wave is weak and resting pressure in LES is high
16
Q
sclerederma
A
may present w/reflux due to inadequate LES tone
17
Q
stimulation of gastric motility
A
parasympathetics ( Ach and gastin)
local distension
18
Q
inhibition of gastric motility
A
low pH inhibits relase of gastrin
feedback from duodenal overload (neuronal and hormonal)
19
Q
stomach emptying rate
A
liquids > CHO > proteins > fat
20
Q
what will slow gastric emptying
A
CCK
GIP
Secretin
all by increasing pyloric constriction
21
Q
ileocecal sphincter
A
usually closed
distention of ileum relaxes it
distention of colon constricts it
22
Q
haustrations
A
bulges along colon due to segmental contractions
23
Q
mass movements
A
of colon
propulsive
more prolonged then peristaltic movements of small intestine
24
Q
MMC
A
migrating myoenteric complex propulsive movement initiated during fasting which begins in stomach repeats every 90-120 min during fasting correlated w/high levels of motilin prevents back flow of bacteria
25
defecation
reflex involving CNS
26
parotid secretions
entirely serous
27
submandibular and sublingual secretions
mixed serous and mucous
28
salivary secretions
under parasympathetic control
29
saliva production
initial formation in acinus via indirect Cl pump (powered by Na/K ATPase)
initially fluid is isotonic, then NaCl reabsorbed so final solution is hypotonic
30
composition of salivary secretions
```
low in Na and Cl
high in K and HCO3
pH =8
alpha-amylase
mucus, glycoproteins
immunoglobulins and lysozymes
low tonicity
```
31
gastric secretions
epi cells covering gastric mucosa secrete highly viscous alkaline fluid
pH = 1
32
NSAIDS
decrease secretion of mucin and bicarb
33
parietal cells
HCL
| IF
34
Chief cells
pepsinogen is converted to pepsin by HCL
pepsin is active only in acid pH
pepsin digests proteins to peptides
35
mucus neck cells
mucus and bicarb
36
ionic composistion of gastric secretions
high in H, K, Cl
low in Na
greater secretion rate higher H and lower Na
37
stimulation of acid secretion
```
Ach
histamine (locally released)
gastrin
distention of stomach
these also stimulate chief cells
```
38
inhibition of acid secretion
pH of stomach decreases to 2.0
| negative feed back
39
cellular mechanism of acid secretion
- parietal cells extracts CO2 from aa
-in cell carbonic anhydrase convertes water and CO2 to H and HCO3
-H pumped across apical membrane creating gradient for HCO3 to flow down across the basal membrane
Cl diffuses across apical membrane
vv blood leaves alkaline
40
pancreatic secretions
acini and ducts similar to salivary glands
| primarily under influence of secretin and CCK
41
stimulation of pancreatic secretions
cholinergic nn to pancreas stimulate secretion of both enzymes and aqueous components
stretch receptors in stomach
42
inhibition of pancreatic secretions
sympathetics
43
enzymatic components of pancreatic secretions
trypsin inhibitors present in pancreatic secretions prevent activation of proteases in pancreas
44
pancreatic amylases
secreted as active enzymes
hydrolyze alpha 1,4 glucoside linkage of CHO -> alpha limited dextrins, maltotriose (trisaccharide), and maltose (disaccharide)
CANNOT hydrolyze beta linkages of cellulose
45
pancreatic lipases
secreted as active enzymes
needs colipase to be effective
digest into 2 FFAs and one monoglyceride
46
cholesterol esterase
hydrolyzes cholesterol esters to yield cholesterol and FAs
47
pancreatic proteases
secreted as zymogens
trypsinogen activated by enterokinase to trypsin
chymotrypsinogen activated by trypsin to chymotrypsin
procarboxypeptidase activated by trypsin to carboxypeptidase
48
enterokinase
secreted by lining of small intestines, not a BBE
49
fluid and electrolyte components of pancreatic secretions
aqueous components from epi cells lining ducts
fluid is isotonic
HCO3 and Cl concentration vary reciprocally: high flow high bicarb and low Cl
HCO3 active transport into lumen
Cl via ClCh (broken in CF)
50
primary bile acids
known as cholic acid and chenodeoxycholic acid
| synthesized by liver from chlesterol
51
conjugated bile
```
conjugated with glycine
water soluble
ionized at neutral pH
aka bile salts
secreted by liver
```
52
secondary bile acids
formed by deconjugation and dehydroxylation of primary bile salts by intestinal bacteria -> deoxycholic acid and lithocholic acid
53
lithocholic acid
hepatotoxic
| excreted
54
micelle formation
when bile salts become concentrated
| water soluble spheres with a lipid soluble materials in aqueous medium of bile fluid and small intestines
55
micelle function
vital for digestion, transport, and absorption of fluid soluble substances from duodenum to distal ileum
in distal ileum bile salts actively reabsorbed and recycled
56
stercobilin
produced from metabolism of bilirubin by intestinal bacteria
brown color of stool
57
control of bile secretion and gallbladder contraction
secretin causes secretion of HCO3 and fluid
secretion of bile from liver due to concentration gradient
CCK causes gallbladder contraction and sphincter relaxation
58
small intestine
most prominent feature is villi
surface of epi have microvilli
water and electrolyte reabsorption greatest at villus tip
water and electrolyte secretion from bottom of crypts of lieberkuhn
59
crypt secretion
Na-K-Cl transporter in basolateral membrane (Na down its gradient)
elevated Cl and neg intracellular potential drives Cl thru apical membrane
luminal Cl pulls water, Na and other ions
60
Cholera toxin
activates apical ClCh increasing water and electrolyte secretion
countered by glucose solution
61
triglycerides in stomach
fatty material pulverized to decrease size and increase surface area
62
triglycerides in small intestines
bile micelles emulsify fat and pnacreatic lipase digest it
63
triglyceride general
micelles and pancreatic lipases required for digestion
| end products are 2-monoglycerides and fatty
64
CHO mouth
salivary amylase begins digestion and conitnues in stomach
65
CHO small intestines
pancreatic amylase required
hydrolysis of starch mostly in duodenum
BBE
66
BBE for CHO
splitting of tri, di, and oligosaccharides
alpha-dextrinase, isomaltase, maltase
highest activity in jejunum
necessary b/c disaccharides cannot be absorbed
67
alpha-dextrinase
aka alpha-glucoamylase
| cleaves terminal alpha 1.4 bonds -> free glucose
68
lactase
hydrolyzes lactose -> glucose and galactose
69
sucrase
sucrose -> glucose and fructose
70
maltase
maltose and maltortirose -> glucose
71
proteins stomach
pepsin begins digestion, but not essential
72
proteins small intestines
digestion continues w/pancreatic proteases (trypsin, chymotrypsin, elastase, caboxypeptidases
digestion completed by BBE dipeptidase, tripeptidases and aminopeptidases -> aa, dipeptides and tripeptides
73
carbohydrate absoption
luminal membrane: glucose and galactose are actively absorbed linked to Na
fructose absorbed independently by facilitated diffusion
basal membrane: monosacchardies are absorbed passively via facilitated diffusion
74
protein absoption
luminal membrane: aa transported by secondary active transport linked to Na, small peptides by Na-H antiporter
basal membrane: simple diffusion and protein mediated transport
75
lipid absorption
micelles diffuse across BB- rate limiting step
| in mucosal cells triglycerides resynthesized to form chylomicrons which leave via lymphatics
76
electrolytes duodenum
hypertonic fluid enters becoming isotonic
most divalent ions and water soluble vitamins begins here and continues thru small intestines
igested Fe and Ca form insoluble salts
acid environment of stomach dissolves them and allows them to be absorbed in duodenum
Fe2+ only can be absorbed in duodenum
77
electrolytes jejunum
net absorption of water and electrolytes
| identical to cells lining nephron proximal tubule
78
ileum electroyltes
reabsorption of water, Na, Cl, K, continues with secretion of HCO3
distal ileum biel alts and IF w/B12 absorbed
79
colon and electrolyes
no digestive enzymes or proteins transporters
only limited resorption of water NaCl
target for aldosterone to increase resorption of Na, water, and secretion of K
80
secretory diarrhea
oversecretion of fluid and electrolytes
| cholera toxins
81
malabsorptive diarrhea
improper absoprtion of nutrients -> osmotic effect
| celiac disease and lactose intolerance
82
executive disease
mucosal destruction causes output of purulent bloody stool
83
hyperactivity of intestines
accelerated movement water cannot be reabsorbed
| IBD
