Pathophys - 3, 4, and 5 Flashcards
1
Q
valvular function of illeocecal junction
A
prevents backflow into SI mechanically
2
Q
sphincter function of illeocecal junction
A
regulates movement of ileal contents into large intestines
3
Q
functions of LI SM
A
mixes chyme (enhances fluid/electrolyte absorption), propels fecal material
4
Q
parasympathetic input of LI
A
vagus innervates proximal colon, pelvic nerves (S2-4) distal colon and rectum/anus
5
Q
what innervates the external anal sphincter
A
puedenal nerves
6
Q
what is the purpose of haustral contractions
A
mixing movements facilitate fluid and electrolyte reabsorption
7
Q
what is the purpose of propulsive movements
A
move feces to rectum/stimulate defecation reflex
8
Q
what is the distance of the propulsive movements
A
transverse colon to sigmoid colon or rectum
9
Q
when do propulsive movements occur
A
after meals, reflexes - gastocolic, duodenocolic reflex
10
Q
what are the three levels of control of defecation
A
intrinsic reflex, spinal cord reflex, involvement of higher centers
11
Q
valsalva maneuver
A
deep breathe, closure of glottis, and increased abdominal pressure ; work to move fecal contents downward
12
Q
_____ can make defecation difficult
A
spinal injury (need digitally or edema)
13
Q
digestion involves what process to absorb nutrients in small intestines
A
hydrolysis (addition of water)
14
Q
monomer for carbs
A
monosaccharides
15
Q
monomer for proteins
A
small peptides and amino acids
16
Q
monomer for fats
A
2-monoglycerides and fatty acids
17
Q
digestive enzymes in stomach
A
pepin
18
Q
digestive enzymes in salivary glands
A
a-amylase, lingual lipase
19
Q
digestive enzymes in pancreas
A
amylase, trypsin, chymotrypsin, carboxypeptidase, elastase, lipase-collapse, cholesterol esterase
20
Q
what digestive enzymes are in the intestinal mucosa
A
enterokinase; sucrase, maltase, lactase, trehahalse, isomaltese, amino-oligopeptidase dipeptidase
21
Q
how does enterokinase activate trypsinogen
A
cleaving hexapeptide from N-terminal end to form trypsin
22
Q
what is the surface area increase for SI
A
1000-fold
23
Q
increase in folds of kerckring
A
3-fold increase in SA
24
Q
what are folds of kerckring controlled by
A
muscularis mucosa
25
what is the fold increase in villi
10-fold increase
26
what is the fold increase in SA
20-fold increase
27
site at which alot of enzyme reaction details occur
microvilli brush border
28
what happens for babies to allow large proteins (immunoglobins) in
endocytosis
29
where does endocytosis occur in adults
ileum for absorption of vitamin B12
30
what is the most important process in SI to make absorption of nutrients possible
sodium electrochemical gradient
31
what can be use for drug absorption if someone has N/V or problems swallowing
rectal catheter
32
a nutrient must cross ____ barriers to be absorbed by blood or lymph
8
33
where do lactose and sucrose get digested
only at brush border
34
where does starch digestion occur
begins with a-amlyase in salvia, continues in SI with pancreatic amylase, final digestion at brush border
35
what is the final product of carb digestion
monosaccharides, mostly glucose
36
what is the rate-limiting step in carb assimilation
absorption
37
how is fructose getting across the membrane
facilitated diffusion (no energy needed, just concentration gradient)
38
how are glucose and galactose getting across the membrane
secondary active transport, SGLUT-1 (energy from NA+/K+ ATPase)
39
lactose intolerance
acquired lactase deficiency caused by absence of brush border lactase
40
Glut-1 deficiency
lack of glucose galactose carrier
41
where does the digestion of AA occur
intestinal lumen, stomach (pepsin, digests collagen), SI
42
what is at the brush border (proteins)
oligopeptidases, dipeptidases
43
what is digested in cytoplasm of mucosal cells (proteins)
(Di, tri-peptidases)
44
how do proteolytic enzymes get digested
digest themselves
45
pancreatic insufficiency
decreased absorption of protein - nitrogen in stool
pancreatitis or CF
46
congenital absence of trypsin
no trypsin - no other proteolytic enzymes, protein malabsorption
47
Hartnup disease
cannot absorb neutral AA (tryptophan); neutral AA can still be absorbed as di- and tri-peptides (proof of separate carrier system)
48
where does the first step of fat absorption occur
SI
49
where are chylomicrons secreted
lymph system and go to thoracic duct where they enter the subclavian vein
50
what does LDL do
takes cholesterol from the liver to the rest of the body
51
what does HDL do
primarily takes cholesterol form body tissue back to liver
52
difference between HDL and LDL
high amount increase risk of HD, high amounts reduce risk
53
hypertriglyceridemia
accumulation of large quantities of fat (lipoproteins) in the blood
54
what are the three main processes must occur for triglyceride to be absorbed in the blood
emulsification, enzymatic digestion, reconstitution of triglyceride and chylomicron formation
55
Cirrhosis of the liver ____ resistance
increases
56
Ascites
accumulation of fluid in the gut coming from liver disease
57
what is the resistance, pressure, and flow of liver?
low resistance, low pressure, high flow
58
Major functions of the liver
filtration and storage of blood, formation of bile, storage of vitamins/iron, formation of coagulation factors, metabolism
59
what is the liver lobule a pathway for
blood and lymph
60
Kupffer cells
phagocytic cell forming lining of sinusoids in liver to breakdown RBCs
61
what can decrease liver blood volume
exercise/hemorrhage (sympathetic stimulation)
62
what can increase liver blood volume
heart failure (as much as 1 L)
63
___% of body lymph is formed in the liver
50
64
where does lymph flow in the liver
through the space of Disse and collects in lymph vessels
65
what does increased sinusoidal pressure increase
lymph production (liver sweats lymph, fluid accumulates in abdominal cavity)
66
what leaks fluid and proteins into space of disse
porous fenestrations
67
where are Kupffer cells located
liver sinusoids
68
what compromises liver reticuloendothelial system
tissue macrophages (Kupffer cells)
69
what is the main cellular system for removal of particulate materials and microbes from circulation
kupffer cells
70
what can you make glucose out of
fat and protein (liver breaks it down and spits out new glucose)
71
where does gluconeogenesis occur
only in the liver
72
what can the liver form (metabolism)
intermediate metabolites and glucose from galactose/fructose
73
what does excess glucose after meals get converted to
glycogen (glycogenesis)
74
what does decreased glucose between meals cause
stimulation of depolymerization of glycogen (glycogenolysis)
75
what does liver do to amino acids
removes the nitrogen from the molecule
76
what is the liver's function in metabolism of proteins
demination of amino acids, formation of plasma proteins, synthesis of nonessential amino acids (12 that we can make), removal of ammonia by synthesis of urea
77
what does the liver require to make prothrombin, Factors VII, VIII, IX, and X
vitamin K
78
liver disease or vitamin K def lead to
bleeding abnormalities
79
Hemophilia
recessive X-linked disorder(rare in females); cannot make Factor XIII, cannot coagulate blood well
80
Factor VIII
anti hemophilic factor; encoded by F8 gene on X chromosome
81
what is the liver's role in fat metabolism
conversion of carbs and proteins to fat, beta oxidation of fatty acids, synthesis of special lipids (cholesterol - 80% converted into bile salts, phospholipids, lipoproteins)
82
what is the main form of fat used in the body
triglycerides
83
what do phase 1 reactions do to parent drug
convert it into polar metabolite with functional group; metabolite usually inactive
84
what do phase 2 reactions do to parent drug or phase 1 metabolite
an endogenous substrate is attached to a functional group (going to plasma)
85
bilirubin plays a role in ____
anti-oxidation, inflammation
86
what are the forms of bilirubin
conjugated and unconjugated (direct and indirect)
87
what is the number 1 protein in blood
albumin
88
direct bilirubin
conjugated
89
where does bile go when it leaves the gut
feces, urine, enterohepatic circulation
90
what do liver cells do with bilirubin
uptake, conjugation, and excretion
91
what does too much bilirubin cause
jaundice
92
overproduction of bilirubin
hemolysis (UC)
93
defection excretion of bilirubin
obstruction - cancer, gallstones
cirrhosis, hepatitis
C
94
defection conjugation of bilirubin
neonatal jaundice (UC)
95
treatment for neonatal jaundice
exposure to blood light from fluorescent tubes; transforms unconjugated bilirubin into a water-soluble photoisomer that can be excreted by kidneys
96
what is the cause of jaundice in new-borns
underdeveloped state of smooth endoplasmic reticulum (makes bilirubin soluble)
97
what is the role of bile
fat emulsification and absorption; medium for excretion of bilirubin and cholesterol
98
what does the gallbladder store
stores and concentrates bile
99
what does gallbladder mucosa absorb
water and most electrolytes (not Ca+)
100
when does gallbladder begin to empty
when food, esp fat, enter duodenum (CCK, nervous - Vagus/ENS)
101
what is the most abundant solute in bile
bile salts
102
what does CCK do
contracts gallbladder and relaxes sphincter of Oddi
103
what has a major effect on emptying gallbladder
duodenal peristaltic waves
104
what are the two stages bile is secreted in
hepatocytes - secrete primary bile constituents, bile ducts- addition of water, Na+, HCO3-
105
what does the formation of bile salts start with
cholesterol
106
bile salts are ____
amphipathic
107
what does the amphipathic nature of bile enable it to do
emulsify lipids, transport lipids
108
black, foul-smelling stool (melena)
intestinal bleeding (stomach and upper SI), due to ulcers, tumors; ingestion of iron and bismuth
109
maroon stool
intestinal bleeding (middle intestine or prox colon due to ulcers, tumors, Crohn's disease, ulcerative colitis
110
Clay-colored stool
lack of bile due to blockage of main bile duct
111
pale, yellow, greasy, foul-smelling stool
malabsorption of fat due to pancreatic insuff, as seen with pancreatitis, pancreatic caner, CF, and celiac disease
112
what is the most common cause of cirrhosis
excessive alc use
113
steatohepatitis
fatty liver accompanied by inflammation, which leads to scarring of liver and cirrhosis
114
what do complications of cirrhosis include
jaundice, ascites, peripheral edema, bleeding esopha varices, blood coagulation abnormalities, coma and death
115
what are the majority of gallstones
cholesterol
116
what is the key event leading to most gallstones
precipitation of cholesterol in bile
117
what are the causes of cholesterol precipitation
too much water reabsorbed, too much cholesterol, inflammation of gallbladder, too much absorption of bile salts and lecithin
118
what are 10% of gallstones
pigment stones
119
What are the segments of the alimentary tract?
mouth, pharynx, esophagus, stomach, SI, LI, spinchters between segments
120
What are the layers of the GI Tract (outside to inside)?
serosa, longitudinal muscle, myenteric nerve plexus, circular muscle, submucosa, submucosal nerve plexus, muscular mucosa, mucosa, epithelial lining
121
What are the parts of the ENS?
Myenteric & submucosal (meissner's) nerve plexus
122
What are the two structurally related families of GI Peptides?
Gastrin & CCK
- Secretin, GIP, VIP, glucagon
123
preprohoromone
precursor protein to one or more prohormones, which are in turn precursors to peptide hormones
124
What is the hypokalemia associated with gastrinoma caused by?
loss of GI secretions in the stool
125
What do all molecular forms of gastrin share?
AA seq
126
What are the four steps required to establish existence of GI hormone?
physiological release, effects independent of nervous system, isolated substance has physiological effect, chemical identification and synthesis
127
What are all horomones in the GI?
peptides
128
What are the symtpoms of Gastrinoma: Zollinger-Ellison Syndrome?
duodenal ulcers, diarrhea, steatorrhea, hypokalema
129
What does hypergastrinemia cause?
hypersecretion of acid, increased parietal cell mass, constant stimulation of hyperpastic mucosa
130
What happens if too much gastrin is secreted (gastrin-secreting tumor)?
mucosal hyperplasia and hypertrophy
131
What do you use to diagnose Gastrinoma?
ChiRhoStim (synthetic secretion); blood test (> 120 pg/mL gastin)
132
Where is somatostatin (peptide) found?
gastric/duodenal mucosa and pancreas
133
What is somatostatin (peptide) release stimulated/inhibited by?
acid, inhibited by Ach
134
What does somatostatin (peptide) do?
Inhibits parietal cell acid secretion, gut hormones, and gastrin
135
What does Histamin do?
stimulates acid secretion, H2 receptor blockers
136
What causes Histamines release?
Gastrine and Ach cause release from pariteal cells in stomach
137
Where is VIP?
gut mucosa and SM
138
Where is GRP (Bombsein)?
Gastric mucosa
139
Where is Enkephalins?
Gut mucosa and SM
140
What does VIP do?
relaxation of gut SM
141
What does GRP do?
increase gastrin release
142
What does Enkephalins do?
increases SM tone
143
What plexuses are involved in intrisic control?
Myenteric and Submucosal plexus
144
What does the parasympathetic system do in terms GIT?
mainly stimulates (Ach)
145
What does sympathetic system do? (GIT)
mainly inhibits (NE)
146
What is the composition of the ENS?
cell bodies, axons, dendrites, nerve endings
147
Where is the innervation of the ENS?
gut cells, sensory nerves, other neurons
148
What is the integration of the ENS?
can occur entirely within ENS, can function independent of ANS
149
What are the transmitters in the ENS?
many excitatory and inhibitory
150
What is the location of the ENS?
What is the location of the ENS?
151
What is the main function of the myenteric plexus?
controls GI motility
152
What are stimulatory influences of myenteric plexus?
increased tonic control, increased contraction frequency/intensity
153
What are inhibitory influences of myenteric plexus?
decreased sphincter tone (relax) - pyloric, ileocecal, LES
154
Where is the submucosal plexus located?
mucosal layer from esophagus to anus
155
What is the function of the submucosal plexus?
local control (secretion, absorption, contraction of mucular mucosa)
156
What is the cranial divison of the parasympathetic innervation?
Vagus N. - first half of gut
157
Where do PS neurons synapse?
closer to organ
158
What is the first half of the gut innervated by?
vagus n.
159
What is the sacral divison of the parasympathetic innervation?
second half of the gut - pelvic n.
160
What does parasympathetic innveration stimulate?
excites ENS
161
What other fibers PS neurons contain?
afferent sensory fibers (per--> central)
162
What is the pattern of neurons in SI?
short pregang, long postgang
163
What does SI do in GI tract?
inhibits activity of ENS and inhibits SM
164
What neurotransmitters cause excitatory affects in the ENS
ach, substance P, serotonin
165
What are the purposes of chewing?
break cells, increases surface area (decreases particle size), mixes food with saliva
166
What does salvia mixing with food do?
starts breaking down carbs and fat (a-amylase, linguial lipase)
167
What is the innervation of chewing
168
cystic fibrosis
salivary Ca+, Na+, and protein are elevated (also true for bronchial secretions, pancreatic juices, and sweat)
169
what can cause xerostomia
drugs, capillary perfusion decreased, radiation, autoimmume
170
xerostomia
dry mouth
171
what directly increases salivation
symp NS
172
why is mucous composition essential for digestion
adherees, body (coat well), low resistance, self adherent, resistant to digestion, buffering capacity
173
what is the composition of mucus
thick secretion that is mainly water, electrolytes, and glycoproteins
174
where are the main secretions coming from for saliva
parotid and submandibular gland
175
what is serous secretion
watery secretion, a-amylase and lingual lipase
176
what are the two types of salvia secretions
serous and mucus
177
where is the biggest pH jump in GI tract
stomach --> small intestines
178
Chewing reflex
food --> muscles of mastication relax --> jaw drops --> stretch reflex --> rebound contraction --> lining of mouth
179
What is the innervation of chewing
5th crainal nerve (trigeminal), controlled by nuceli in brain
180
What are the purposes of chewing?
break cells, increases surface area (decreases particle size), mixes food with saliva
181
what is the treatment of drooling
anticholingeric drugs, surgical removal of the sublingual glands, retroposition submandibular ducts
182
what do CF patients lack
chloride transporters (CFTR)
183
primary aldosteronism
excess aldosterone; salivary NaCl close to zero, salivary K+ high
184
What is the PNS pregang eff neuron neurotransmitters?
ach
185
What is the PNS postgang eff neuron neurotransmitters?
ach
186
What are the inhibiory neurotransmiters for the ENS?
VIP, NO
187
What stimulates GI afferent neurons?
distention of gut wall, irritation, chemical stimuli
188
What can stimulation of sensory afferent neurons (GI) do?
excite or inhibit (intestinal movements & secretions)
189
Pathway of vagovagal reflexes
stomach/duodenum --> aff. n ---> brain stem --> eff n--> stomach/duodenum
190
Defecation reflexes pathway
colon/rectum --> aff n. --> spinal cord --> eff. n. --> colon/rectum
191
What do pain reflexes do to the GI tract?
overall inhibition
192
What are the gastrointestinal reflexes?
gastrocolic, enterogastric, colonileal (vagovagal, defecation, pain)
193
ong loop GI reflexes pathway
gut --> aff. n --> prevertebral ganglia --> eff n. ---> gut
194
What are local GI reflexes?
afferent fibers from gut terminate in ENS, affect (+/-) secretion, peristalsis mixing movements
195
syncytium
nucleated mass of protoplasm produced by merging of cells
196
why are gap junctions important in GI SM?
signal propogation, unitary
197
what are the pacemaker cells of GI slow waves
interstitial cells of cajal
198
what dictates the max frequency of SM contraction
pacemaker (interstital) cells
199
what are rhythmical changes in membrane potential caused by variations in
sodium conductance
200
what is variable amplitude in slow waves affected by
nervous/hormonal stimuli
201
what are the frequency of spike potentials affected by
nervous/hormonal stimuli;
202
what happens when frequency of spike potentials increases
stronger contraction
203
what cause SM contraction
true APs
204
what are spike potentials stimulated by
stretch, ach, PS
205
what are hyperpolarizations of SM stimulated by
noreip, symp
206
what are stimuli that initiate peristalsis
distention, irritation, PS
207
what is required for peristalsis
myenteric plexus
208
what decreases peristalsis
atropine
209
what does atropine do
blocks Ach receptors
210
what are the main feed arteris of the GI
celiac a., SMA, IMA
211
whats the venous drainage of GI
portal vein --> liver sinusoids --> hepatic vein
212
what is gut blood flow proportional to
local acitivity
213
what causes activity - induced blood flow
vasodilator hormones (gastrin, secretin, CCK), low oxygen
214
what is the PNS control of GI blood flow
increases gut activity and increases blood flow
215
what is SNS control of gut blood flow
decreases blood flow
216
fatty acids and triglycerides
high density energy storage
217
phopholipids
membrane component, contain precursors for bio active substances, modulate activities of membranes enzymes&transporters
218
cholesterol
impt part of membranes, control fluidity and protein function. precursor for bile acids and liver makes most of it (most cells can syn from acetyl CoA)
219
what are most dietary lipids
neutral fat or triglyceride
220
acini
grape-like clusters of cells that store and secrete digestive enzymes
221
ducts
secrete bicarbonate
222
two types of pancreatic ducts
intercalated ducts (acini), intralobular ducts (intercalated)
223
role of pancreas in chyme going into SI
bicarb solution to neutralize acid chyme, digestive enzymes for all food types
224
what cleaves proteins to polypeptides
trypsin and chymotrypsin
225
what cleaves polypeptides to AA
carboxypeptidase
226
what is the only luminal enzyme for carb digestion
amylase
227
what digests starches and glycogen to disaccharides
starches and glycogen
228
what enzymes digests fat into fatty acids and monoglycerides
pancreatic
229
what helps the pancreas to not digest itself
pancreatic proteolytic enzymes are stored and secreted in an inactive form (also, trypsin inhibitor is present)
230
what converts trypsinogen to trypsin
enterokinase
231
where is enterokinase located
intestinal mucosal cells
232
what does trypsin
autocatalytic activation (breakdown proteins in intestines)
233
what neutralizes acid chyme
bicarb (secretin-induced)
234
where does the pancreas receive signals from for regulation
stomach and intestines
235
what hormones potentiate effects of secretin on water and bicarb secretion
CCK and ach
236
chronic pancreatitis causes
alcohol (adults) and CF (children)
237
acute pancreatitis causes
gallstones
238
what do brunner's glands secrete
alkaline mucus (protect intestines from acid)
239
what are brunners glands stimulated and inhibited by
stimulated - local irritatation (vagus, Ach)
inhibited - sympathetics (NE)
240
mucous/goblet cells
secrete mucus that lubricates and protects the intestinal surfaces
241
intestinal stem cells
differentiate into the special cells of the intestinal epithelium, which renews throughout life
242
paneth cells
secrete anti-microbial compounds and other compounds known to be important in immunity and host defense, thereby contributing to maintenance of the GI barrier
243
how does SI motility contribute to digestion and absorption?
mixing chyme, circulation of chyme, propulsion of chyme
244
Most water and electrolyte recovery occurs in what GI section?
LI
245
What “glands” in small intestine secrete alkaline mucus?
Brunners
246
The swallowing center is located where?
Medulla (of brain stem)
247
Dehydration has what effect on salivary flow?
Inhibits
248
True or false? The intrinsic defecation reflex is controlled within the enteric nervous system
True
249
Blood returning to liver from circulation comes through which common vein?
Portal
250
Rhythmical changes in membrane potential in smooth muscle caused by variance of sodium conduction are called:
Slow waves
251
Intrinsic neural control of GI tract is via which system?
ENS
252
Which accessory organ stores bile?
Gallbladder
253
Q: The parotid gland secretes what?
Saliva (serous)
254
Parasympathetic stimulation does what to mucus secretion in large intestine?
Increases
255
The cephalic phase of gastric secretion relies on what nerve?
vagus
256
HCl is formed in what cells in the stomach?
Parietal
257
The G cells in the antrum and duodenum release what?
Gastrin
258
Luminal digestion of proteins produces a majority of what product?
A: Di- and tri-peptides
259
Final digestion of CHO happens at what location?
Brush border
260
Which structures increase the surface area of the SI 10x and contain capillaries and a lacteal?
villi
261
The majority of nutrient absorption in the gut happens where?
SI
262
Which buffer helps neutralize acid to create optimal conditions for digestive enzymes?
bicarb
263
Which enzyme is the first to start breaking down fats?
lingual lipase
264
What enzyme breaks down phospholipids?
A: Phospholipase
265
Amylase is a common term for an enzyme that breaks down what macronutrient?
CHO
266
What word describes enzymes that cleave proteins to polypeptides?
Proteolytic
267
Lipids must form which structures to be absorbed into enterocytes?
Micelles
268
Which peptide is released by the duodenum in response to acid and the presence of fatty acids?
Secretin
269
Lipids form which structures to be transported from the enterocyte through lymphatic circulation?
Chylomicrons
270
In arterioles, which enzyme binds chylomicrons and hydrolyzes triglycerides to FFA + glycerol?
lipoprotein lipase
271
Which type of lipid synthesis is blocked by statin drugs?
Cholesterol
272
Which receptor is used to transport glucose and galactose across the brush border into the intestinal cells?
SGLUT1
273
Which hormone is most active in the antrum of the stomach?
Gastrin
274
Which hormone stimulates insulin release?
Glucose-Dependent Insulinotropic Peptide
275
What part of the pancreas secretes bicarbonate?
Ducts
276
Vitamin K is needed by the liver to form what?
Coagulation factors
277
The liver conversion of a parent drug to a more polar metabolite is called what?
Phase 1 or first pass metabolism
278
Which duct combines secretions of the pancreas and the gallbladder?
Common bile duct
279
The majority of all gallstones are composed of what substance?
Cholesterol
280
What term describes the location where the intestinal lumen meets SI epithelial cells ?
Brush border
