Exam 3: GI Flashcards
(384 cards)
1
Q
what is mucus composed of
A
mainly water
electrolytes
glycoproteins
2
Q
what are properties of mucus
A
adherent-sticks to food
body-coats well
low resistance-lubrication
self adherence-sticks together
resistant to digestion
buffering capacity
3
Q
what shape must food be to swallow
A
bolus
4
Q
why does mucus need to be resistant to digestion and have buffering capacity
A
can tolerate the HCl and low ph of stomach
5
Q
what are the two types of saliva
A
serous
mucous
6
Q
what is contained in serous saliva
A
watery secretion
contains a-amylase
7
Q
what does amylase digest
A
carbs
8
Q
what is contained in mucous saliva
A
mucin
9
Q
can humans digest cellulose
A
no
10
Q
how much saliva is secreted a day
A
800-1500 ml/day
11
Q
what is the maximum rate of saliva secretion
A
4ml/min
12
Q
what kind of saliva does the parotid gland secrete
A
serous
13
Q
what kind of saliva does the submandibular gland secrete
A
mucous and serous
14
Q
what kind of saliva does the sublingual gland secrete
A
mucous/serous
15
Q
what kind of saliva does the buccal gland secrete
A
mucous
16
Q
what two glands make up 90% of saliva secretion
A
parotid and submandibular
17
Q
what is the cephalic phase of digestion
A
mouth watering in response to seeing or smelling food
(prepares)
18
Q
what nerve controls the cephalic phase of digestion
A
vagus
19
Q
what happens in the gastric phase of digestion
A
initiates digestion through stimulating:
pepcin
chief cells
parietal cells
mucous cells
20
Q
what happens in the intestinal phase of digestion
A
absorption
nervous and hormonal mechanisms
21
Q
what are the three phases of digestion
A
cephalic
gastric
intestinal
22
Q
why doesnt the stomach digest itself
A
gastric mucosal barrier/mucous cells
23
Q
what is the anatomical portion of the gastric mucosal barrier
A
cell membranes and tight junctions between cells
24
Q
what is the physiological portion of the gastric mucosal barrier
A
diffused H ions are transported back to lumen
25
what is found in 95% of patients with duodenal ulcers
H pylori
26
what is found in 100% of gastric ulcers (when alcohol asa, NSAIDs are eliminated)
H pylori
27
what are propterties of H pylori
gram -
high urease activity
can withstand acid
NH4 damages epithelial cells in GU
increases acid secretion
28
what are risk factors for ulcers
NSAIDS
H. pylori
alcohol
29
how do NSIADS affect stomach
increased acid production
decreased mucous production
30
what must happen when chyme moves into small intestines
1-acid must be neutralizied
2-macromolecules (proteins, fats, starch) must be broken down for absorption
31
does pepcin digest protein?
no, it digests collagen which binds muscles together
32
what allows acidic chyme to be neurtalized
bicarb from pancreas
33
how does the pancreas help break down macromolecules
secretes digestive enzymes for all food types
34
what are the grape like structures in the pancreas that store and secrete digestive enzymes
acini
35
what secretes bicarb form the pancreas
ducts
36
what receives secretion from the acini in the pancreas
intercalated ducts
37
what receives the fluid from intercalated ducts in pancreas
intralobular ducts
38
what do islets of langerham do
release insulin and glucagon into the blood stream
39
what type of enzymes are prodouced in islets of langerham (end or exo)
endocrine portion
40
what kind of enzymes (endo or exo) are produced in the acini
exocrine
41
what lines the ducts in the pancreas
chloride channel, opens and allows sodium bicarb to escape
42
what do the chloride ducts in the pancreas transport
bicarb
43
what is produced in pancreas
insulin and glucagon
amylase, lipase
tripsonigen
chymotrypsin
44
what two pancreatic enzymes cleave proteins into polypeptides
trypsin
chymotrypsin
45
what kind of enzymes are trypsin, chymotripsin, carboxypeptidase
proteolytic enzymes
46
what three enzymes breakdown proteins
trypsin,
chymotripsin,
carboxypeptidase
47
what cleaves polypeptides into amino acids
carboxypeptidase
48
what keeps the proteolytic enzymes from eating pancrease
-trypsin inhibitors in cell
-they are all stored and secreted in inactive form
49
what is the precurser to trypsin
trypsinogen
50
what breaks down starches and glycogen into disaccharides
pancreatic amylase
50
what is the precurser to chymotripsin
chymotrypsinogen
51
what is the precurser to carboxypeptidase
procarboxypeptidase
52
what is the only luminal enzyme for carb digestion
amylase
53
all enzymes are secreted in ______ enzyme secretion must be decreased 10-15% of normal to cause problems
excess
54
what are all foods broken down into
proteins
carbs
fats
55
what breaks fats into fatty acids and monoglycerides
pancreatic lipase
56
what breaks phospholipids in fatty acids
phospholipase
57
when you break down fats they are too large to go into blood stream, so what absorbs them
lactiles, into lymph, into venous system
58
what breaks down cholesterol esters in fatty acids
cholesterol esterase
59
What converts trypsinogen to trypsin?
enterokinase
60
where is trypsin inhibitor made
inside the pancreas so trypsin in pancreas is still unable to cause harm
61
what happens when tripsin inhibitor in inhibited or neutralized
pancreatitis
62
where is enterokinase located
located in intestinal mucosa
63
where else is trypisin inhibitor located
in lungs
64
what ph does bicarb neutralize chyme to
7-8
65
what induces bicarb release from pancreas
secretin
66
where is secretin produced
S cells of duodenem
67
how does secretin affect liver
increase bile production in liver
68
how does secretin affect stomach
decreases HCl acid production by parietal cells
69
what produces HCl acid in stomach
parietal cells
70
what increases the rate of exchange between cl and bicarb in pancreas
secretin
71
what stimulates the secretion of fluid and HCO3 in the duodenum
the amount of acid entering the duodenum
72
what stimulates the sescretion of enzymes in the deuodenum
amount of fat and proteins entering the duodenum (not carbohydrates)
73
what stimulates the release of cholesystokinen
fat and aminio acids
74
at what pH is secretin released
<4.5
75
when is the max amount of secretin released
pH <3
76
during meals pH is rarely less than
3.5 or 4
77
what does Brunners glands secrete
alkaline mucus
78
what does the crypts of lieberkuhn do
secretes water like fluid (1800 ml day)
79
where are crypts of lieberkhun located
bottom of interstitial villi
80
why does interstitial villli regrow quickly
crypts of lieberkuhn contain lots of stem cells
81
are their crypts of lieberkuhn in large instestine?
yes, not there are no villi or enzyme, so mostly secrete alkaline mucous
82
what is present in all the digestive tract and alls movement through tract
alkaline mucous
83
what increases mucous production in Gi tract
parasympathetic stimulation
84
what is the major function of the colon
absorption of water, forms stool
85
what stimulates bile release
cholecystokinin responding to lipids
86
What does cholecystokinin do?
its a messenger,
does not do anything on its own,
tell the gall bladder to release bile
87
what is hydrolysis in digestion
adding water to nutrients so they can be absorbed in small intestines
88
what do carbohydrates break down into
monosaccharides
89
what are proteins broken down into
small peptides and amino acids
90
What are fats broken down into?
monoglycerides and fatty acids
91
where does luminial/cavital digestion occur
in lumen of GI tract
92
what carries out luminal digestion
enzymes from salivary glands, stomach, pancreas
93
where does contact/membrane digestion occur
in the brush borders of GI tracts
94
what carries out contact digestion
enzymes on brush border of enterocytes
95
what enzymes are in the salivary glands
amyliase
lingual lipase
96
what enzymes are in the stomach
pepsin
97
what enzymes are in the pancrease
amylase
trypsin
chymotripsin
carboxypeptidase
elastase
lipase-colipase
phospholipase
cholesterol esterase
98
what enzymes are in the intestinal mucosa
enterokinase
sucrase, maltase, lactase, trehalase, extrinase
amino-oligopeptidase
dipeptidase
99
what enzymes are intracellular
dipeptidase
tripeptidase
100
what gets absorbed in the stomach
ethanol, NSAIDs, aspirin
101
what gets absorbed in the duodenum and jejjunum
nutrients,
vitamins,
various ions,
water,
electrolytes
102
what gets absrobed in the ileum
bile salts
vitamin B12
103
what gets absorbed in the colon
water and electrolytes
104
what gets absorbed in the rectum
drugs such as steroids and salicylates
105
what does B12 do
RBCs
106
how many layers do nutrients pass through to get to blood
8 layers
107
what are steps of carbohydrate digestion
1-alpha amylase in mouth (5% in mouth, 40 % in stomach)
2- small intestines pancreatic amylase
3- final at brush border
108
where does lactose (milk) and sucrose digestion occur
only brush border
109
what is lactose made up of
galactose and glucose
110
What is sucrose made of?
glucose and fructose
111
can you absorb lactose and sucrose? or maltose and glu-polymers?
NO
112
80% of all carbs are absorbed as
glucose
10-fructose
10-galactose
113
What is maltose/glu-polymers made of?
multiple glucose molecules
114
what are the steps of protein digestion
1- stomach- pepsin (digests collagen)
2-small intestines (trypsin, )
chymotrypsin, carboxypeptidase to amino acids)
3- brush border
4- cytoplasm cells (di and tri peptides)
115
Proteins are broken down into
peptides and amino acids
116
what are the steps of lipid digestion
1- emulsified by bile (enterokinin)
2-enzymatic digestion (lipase into fatty acid and glycerides)
117
most dietary lipid is
neutral fat or triglycerides
118
what is fat broken down into
fatty acids and glycerol
119
what are micells
a water-soluble transporter to transport fat for absorption into the lactile
120
what percentage of fat is broken down into triglycerides
90%
121
how much fluid enters the body a day from sources
diet -2
saliva- 1
stomach -2
bile -1
pancrease -1
SI -2
122
where is fluid absorbed
duodenum and jejunum- 4
ilium -3.5
colon -1.4
123
what is the movement of water inbody
diffusion/osmotic forces
124
hypotonic chyme results in water
absorption
125
hypertonic chyme results in water
entering intestines
126
chyme is usually what tonicity
isotonic
127
the endocrine system is made up of
anything that makes hormones
128
what two systems keep us in homogenous state
neuro system
endocrine system
129
what is the bodies quick reaction to homogenous state
neuro
130
what is the bodies slow and long lasting reaction to homogenous state
endocrine system
131
endocrine system uses the ________ system to have affect on body
venous
132
where does the paracrine system have affect
cell to cell through interstitial fluid
133
endocrine means it travels in the
blood
134
neuroendocrine means a _________ stimulates a hormone releases that travels in the _________
neuron
blood
135
where does autocrine system have effect
cells releases hormone to affect itself
136
what are the three classes or hormones
peptide/protein hormones
steroid hormones
amine hormones
137
a substance with <100 amino acids is a
peptide/polypeptide
138
a substance with >100 amino acids is a
protein
139
what glands and tissues create peptide/protien hormones
hypothalmus
anteiror pituitiary
posterior pituitary
thyroid
pancreas
liver
parathyroid
placenta
kidney
heart
GI tract
adipocyte
140
how do protein/peptide hormones work
there is a receptor on the surface of the target cell
141
what hormones work on a receptor of the target cell
peptide/proteins
amines
142
steroids are made up of
lipids
143
steroids have their affect by
entering the cell and working in cytoplasm
144
what organs/glands make steroid hormones
adrenal cortex
testes
ovaries
corpus luteum
placenta
kidney
145
What steroid hormones does the adrenal cortex secrete?
cortisol
aldosterone
androgens
146
what steroid hormones do the testes secrete
testosterone
147
what steroid hormones does the ovaries, corpus luteum, and placenta secrete
estrogens, progesterone
148
what steroid hormones does kidney secrete
1,25 dihydroxycholecalciferol
149
what glands/organs secrete amine hormones
hypothalamus
thyroid
adrenal medulla
150
what amine hormone does the hypothaomus secrete
dopamine
151
what does dopamine do
neurotransmitter
movement of spinae eretae
motivation
emotion/feel good
152
what amine hormones does the thyroid secrete
T3 T4
153
what amine hormone does the adrenal medulla secrete
NE
EPI
154
where do all amine hormones come from
tyrosine
155
what is an example of a transport protein
albumin
156
what creates a positive feedback
levels too low, tell you to secrete hormone
157
what creates a negative feedback
levels too low, tell you to stop secreting hormone
158
Where does the pituitary gland sit?
sella tursica
159
which part of the pituitary is vascular driven
anterior
160
which part of the pituitary is neurologically driven
posterior
161
adeno means
glandular
162
antidiuretic hormone (ADH) is also called
vasopressin
163
what is released when the posterior pituitary is stimulated
oxytocin and vasopressin (ADH)
164
what is secreted from the anterior pituitary
growth hormone
adrenocorticotrophic hormone
TSH
FSH, LH
melanocyte stimulating hormone
prolactin
165
what does oxytocin do
Milk letdown and uterine contractions
166
What does ADH do?
increases NaCl and H20 resorption in kidney increased intravascular volume
vasoconstriction
167
what connects the hypothalamus to the pituitary gland
portal system
168
what must be present to cause a release a hormone from anterior pituitary
release hormone in hypothalamus, goes through portal system to anterior pituitary
169
what does GHRH release
GH
170
what does GnRH release
LH
FSH
171
What does PRH stimulate?
prolactin
172
What does CRH stimulate?
ACTH
173
What does TRH stimulate?
TSH
174
what does growth hormone do to liver
IGFs
175
what does FSH and LH do to testes/ovaries
testoserone/estradiol/progesterone production
176
what does prolactin do to mammary gland
produce milk
177
what does ACTH do yo adrenal gland
cortisol
178
what does TSH do to thyroid
release T3 T4
179
what three things is food broken down into
fats
carbs
proteins
180
fats are broken down into
fatty acids and glycerol
181
proteins are broken down into
amino acids
182
Carbs are broken down into
monosaccharides
183
what are the segments of the GI tract
mouth
pharynx
esophagus
stomach
small intestine
large intestine
sphincters
184
what does the liver produce for digestion
produces bile
185
what does bile do
emulsifies fat
186
what does the gall bladder do for digestion
stores bile
187
what tells gall bladder to release bile
cholecystokinins
188
What are the endocrine functions of the pancreas?
insulin
glucagon
189
what does an exocrine gland do
Secrete products into ducts, tears and sweat
190
what does a paracrin gland do
releases hormones to affect neighboring cells
191
what does an endocrine gland do
releases hormone to bloodstream
192
What are the exocrine functions of the pancreas?
amylase (carbs)
lipase (fats)
tripsan (proteins)
193
what does the pancreas release to neutralize the gastric pH
bicarb
194
why does pancreatits lead to duodenal ulcers
pancreas doesnt creat bicarb
195
what do parotid and salivary glands secrete for digestion (and submandibular?)
alpha-amylase to digest carbs
196
anatomy review
197
what is the outside layer of the GI tract
serosa
198
Gi tract muscle shortens the tube (peristalsis)
longitudinal
199
what Gi tract muscle creates intestinal tone
circular muscle
200
what is the inside layer of the Gi tract
mucosa
201
gut wall layers
202
what is the enteric nervous system of the GI tract
myenteric plexus
203
what are the two nervous systems of the GI tract
enteric
autonomic
204
what is the role of the enteric nervous system of the GI tract
create intestinal tone
205
what is the role of the mesentery
Attaches to abd wall
conduit for blood supply
206
which GI nerve plexus is in between longitudinal and circular muscle
myenteric nerve plexus
207
what three things regulate the Gi tract
GI peptides
nerves
smooth muscle
208
all Gi hormones are ________
peptides
209
what is a VIP
vasoactive intestinal peptide (nitrous oxide)
210
can the ENS function without the ANS
yes
211
what NS in the Gi tract creates visceral tone
ENS (enteric nervous system)
212
what is the effect of exciting a sphincter
closes
213
what stimulates the release of gastrin
protein
distention
nervous system
214
What inhibits release of gastrin?
acid
215
Where is gastrin secreted?
G cells in the antrum of the stomach, duodenum, and jejunum
216
what is the action of gastrin
stimulates gastric acid secretion and mucosal growth
217
what stimulates the release of cholecystokinin
proteins
fats
acids
218
where is cholecystokinin released
I cells of the duodenum, jejunum, and ileum
219
what is the action of cholecystokinin
stimulates:
pancreatic enzyme secretion
pancreatic bicarb secretion
gallbladder contraction
growth of the exocrine pancreas
inhibits:
gastric emptying
220
what stimulates secretin release
acid
fat
221
what is the site of aciton of secretin
S cells of duodenum, jejunum and ileum
222
what are the actions of secretin
stimulates:
- pepsin secretion
- pancreatic bicarbonate secretion
- biliary bicarbonate secretion
- growth of exocrine pancreas
inhibits:
- gastric acid secretion
223
what stimulates the release of gastric inhibitory peptide
proteins
fats
carbs
224
what is the site of secretion of Gastric inhibitory peptide
K cells of duodenum and jejunum
225
what are the actions of gastric inhibitory peptide
stimulates insulin release,
inhibits gastric acid secretion
226
what stimulates the secretion of motilin
Fat, acid, nerve
227
what is the site of secretion of motilin
M cells of duodenum and jejunum
228
what is the action of Motilin
stimulates gastric motility and intestinal motility
229
T/F most ulcers are caused by excess HCl
F, its from decreased mucous
230
what breaks down protein
pepsin
231
what stimulates the secretion of pepsin
protein ingestion/secretin
232
what breaks down fats
lipase and bile
233
what is the location of the enteric NS
gut wall from esophagus to anus
234
if sphincter is inhibited it then _______
opens
235
what nervous systems exhibit extrinsic control of the GI tract
parasympathetic
sympathetic
236
what are the two parts of the enteric nervous system
myenteric plexus
submucosal plexus
237
what is the function of the myenteric plexus
controls GI motility
238
what are the stimulatory influences of the myenteric plexus
tone
contraction frequency/intensitry (peristalsis)
239
sympathetic nerves in the bowel are _______ ganglionic
post
240
what are the inhibitory influences of the myenteric plexus
decreased sphincter tone (pyloric, ileocecal, LES)
241
where is the submucosal plexus located
mucosal layer from esophagus to anus
242
what is the function of the submucosal plexus
Secretion
Absorption
Contraction of muscularis mucosa
243
what is the parasympathetic innervation for the first half of the gut
vagus nerve
244
what is the parasympathetic innervation for the second half of the gut
pelvic nerve
245
Where do parasympathetic nerves originate?
pons and sacrum
246
parasympathetic have a _________ postganglionic
short
247
where do the sympathetic nerves for the GI tract come from
T5-L2
248
how does exciting parasympathetic affect GI
increased digestion
249
what kind of influence does the sympathetic have on GI
inhibitory
250
What are excitatory neurotransmitters of the Gi tract
acetylcholine,
substance P,
serotonin
251
what are the inhibitory neurotransmitters of the GI tract
VIP
NO
252
what stimulates sensory afferent neurons in the GI
distension of Gut wall
irritation of gut mucosa
specific chemical stimuli
253
what is function of gap junctions in Gi smooth muscle
helps cells move as one for peristalsis
254
what is a syncytium
When cells are connected together, as by gap junctions, and act as one large cell.
255
what are slow waves
-rhythmical changes in membrane potential caused by variations in sodium conductance
-increased membrane potentials, but not to threshold
256
What is a spike potential/wave
-occurs when slow waves reach threshold
-cause SM to contract
-Ca enters to cause contraction
257
slow waves are controlled by what ion
Na
258
spike waves are controlled by what ion
Ca
259
what is the propulsive movement of the GI tract
peristalsis
260
orad is towards
mouth
261
caudad is to
tail
262
what muscle do peristalsis
circular and longitudinal muscles
263
what stimuli increase peristalsis
1-distension (orad contraction with downstream receptive relaxation)
2-irritation of gut epithelium
3- parasympathetic nervous system
264
how does atropine affect peristalsis
decreases, blocks Ach receptors
265
what is another name for portal circulation
Hepatic
266
where does blood from stomach, intestines go first
liver (portal vein)
267
portal circulation
268
what three branches of the aorta supply the Gi
celiac trunk
superior mesenteric
inferior mesenteric
269
how does a meal affect GI blood flow
increases
270
in villi _______% of oxygen is shunted from artery to vein
what is this called
80%
countercurrent oxygen loss
271
what happens to villi when there is circulatory shock, decreased CO, hypotension, mechanical obstruction
avascular necrosis to tip of villi, sloughs off
272
what absorbs fats into the lymph system
central lacteal in villi
273
how does fat get into blood stream from Gi tract
lymph system
274
what is purpose of chewing
* Breaks cells - breaks apart indigestible cellulose
* Increases surface area
* Mixes food with saliva
- Begins digestion of starches (a-amylase, lingual lipase)
- Lubricates food for swallowing
275
which nerve controls chewing
cranial nerve 5, trigeminal (maxillary and mandibular branches)
276
what stimulates the swallow reflex
bolus in back of mouth
277
what are the three stages of swallowing
voluntary stage,
pharyngeal stage,
esophageal stage
278
what are the 5 processes for swallwoing
1) tongue pushes bolus to soft pallate, soft pallate elevates blocking off nasal passage
2) pharyngeal folds keep large food particles out
3) thyroid cartilage moves up and out, epiglottis folds down to block off trachea
4) upper esophageal sphincter dilates/relaxes
5) esophageal peristalsis
279
where does swallowing reflex come from
pons
280
what is the continuation of pharyngeal peristalsis in the esophagus
primary peristalsis
281
what happens in esophagus after primary peristalsis
secondary peristalsis
282
what induces secondary peristalsis
distension
283
the upper 1/3 of esophagus is _________- muscle
striated
284
the lower 2/3 of esophagus is _______ muscle
smooth
285
how does surgery affect elasticity of esophagus
decreases
286
what keeps air from entering esophagus
upper esophageal sphincter
287
what keeps acid from refluxing into esophagus
lower esophageal sphincter
288
what are the layers of the stomach muscles
longitudinal
circular
oblique
289
what are the functions of gastric smooth muscle
- Relaxes to accommodate food - orad area (receptive relaxation)
- Mixes food with gastric juice - caudad area (retropulsion)
- Propels chyme into duodenum - caudad area (antral pump)
290
what ph does chyme have to be for enzyme function
7
291
what 4 factors increase gastric emptying
1- increased tone of orad stomach
2- forceful peristalsis contraction
3- decreased tone of pyloris
4- absence of segmental contraction in intestine
292
what 4 factors decrease gastric emptying
1- relaxation of orad stomach
2- decreased force of peristaltic contractions
3- increased tone of pyloric sphincter
4- segmentation contraction in intestine
293
activation of intestinal receptors __________ gastric emptying
decreases
294
what stimulates intestinal mucosa receptors
high or low osmolarity
acids
fats
proteins
295
what do fats and proteins trigger for gastric emptying
CCK (cholecystokinin) release increases gastric distensibility which decreases gastric emptying
296
what do acids trigger for gastric emptying
decreases via intrinsic neural reflex
297
what are the two types of movement in the small intestines
peristalsis
segmentation
298
what movement is a propulsive movement
peristalsis
299
what movement is a mixing movement
segmentation
300
what sweeps undigested residue toward colon to maintain low bacteria counts in upper intestine
migrating motility complexes
301
what is the most coordinated, rapid peristalsis
migrating motility complexes
302
what type of intestinal movement happens between meals
migrating motility complexes
303
what mediates migrating motility complexes
motlin
ENS
304
what mediates the peristaltic reflex
ENS
305
what mediates the intestino-intestinal reflex
extrinsic nerves
306
what stimulates gastroileal reflex
meal
ileocecal sphincter relaxes
ileal peristalsis increases
307
spike potentials and thus contractions depends of what two types of input
neural and hormonal
308
What does motilin do?
mediates migratory motor complexes
309
what do serotonin and prostaglandins do
stimulate motility (large quantities in small intestines)
310
what two structures are in the ileocecal junction
valve-prevent backflow
sphincter-regulates movement from ileum to cecum
311
what are the functions of the large intestines
-mixes chyme-enhanvces fluid and electrolyte absorption (haustra)
-propels fecal material (mass movement)
312
(more/less) water is reabsorbed in small intestines than in the colon
more
313
what muscles are in the large intestines
-longitudinal smooth muscle
-circular smooth muscle
-internal anal sphincter
-external anal sphincter
-hausta
314
what is the internal anal sphincter made of
circular muscle
315
what is the external anal sphincter made of
striated muscle
316
where is myenteric plexus concentrated in large intestines
teneae coli
317
where does large intestines receive parasympathetic innervatgion
vagus in proximal colon
pelvic nerves S2-s4 in distal colon, rectum/anus
318
what innervates in external anal sphincter
pudendal nerve
319
what is the purpose of haustral contractions
mixing movements facilitate fluid and electrolyte absorption
320
what is the propulsive movement of the large intestines
mass movement
321
when do mass movements occur
after meals
reflexes like gastrocolic reflex and duodenocolic reflex
322
what are the three levels of control of defecation
intrinsic reflex
spinal cord reflex
involvement of higher centers
323
what are steps intrinsic defecation reflection
1-mass movement goes into rectum
2-rectal distention sends afferent signals through myenteric plexus
3- internal anal sphincter relaxes and IF external anal sphincter is VOLUNTARILY relaxed then defecation
324
what are the steps of spinal cord defecation reflex
1-rectal distension initiates cord reflex afferent signals go to sacral cord and then back to descending and sigmoid colons and rectum
2s2-s4 neurons provide sensory and motor fibers for defecation reflex
325
what is the higher centers defecation reflex
valsava maneuver
326
what sphincters are in intestinal tract
upper esophageal (keeps air from going down)
lower esophageal (keeps acid from going up)
pyloric sphincter (holds food in stomach
ileocecal (small to large, ileum to cecum)
internal anal (myenteric)
external (voluntary)
327
what does the peristaltic reflex do
bowel stretch
proximal contraction
distal relaxation
328
what does the enterogastric reflex do
from duodenum to regulate gastric emtpying
329
what does the gastroileal reflex do
gastric distension relaxes ileocecal sphincter
330
what does the intestino-intestinal reflex do
over distension or injury of bowel segment causes bowel to relax
331
what does gastro and duodenocolic reflexes do
distention of stomach/duodenum initiates mass movement
332
what initiates the defecation reflex
rectal distension initiates defecation
333
Where does bilirubin come from?
It comes from the breakdown of heme, a part of the hemoglobin.
334
What is erythropoiesis?
production of red blood cells in marrow
335
how long to rbcs live
120 days
336
what three areas dispose of RBCs
spleen
liver
marrow
337
what breaks down RBC
macrophages
338
what are RBCs broken down into
heme and globin
339
What is heme broken down into?
iron and bilirubin
340
bilirubin is___________ soluble
lipid
341
unconjugated bilirubin binds with ___________ to go through blood stream and make it non-toxic
albumin
342
bilirubin enters the liver as
unconjugated
343
what cells in the liver break down RBCs
kupffer cells, also form unconjugated bilirubin
344
what substance in the liver changes bilirubin to conjugated form
glucaronic acid
345
conjugated bilirubin is ___________ soluble
water
346
what happens when bacteria in gut attacks bilirubin
changes it back to unconjugated bilirubin (10%)
347
what happens to the bilirubin that is unconjugated by bacteria in bowel
5% (half) excreted in urine (gives yellow color)
5% (half) goes back to liver
348
what gives stool its brown color
conjugated bilirubin
349
what is another name for parietal cells
oxytonic
350
what produces mucus in stomach
mucus cells
351
what produces gastrin in stomach
G cells
352
what produces somatostatin in stomach
D cells
353
what creates HCl in stomach
parietal cells
354
what produces pepsinogen in stomach
chief cells
355
What converts pepsinogen to pepsin?
HCl
356
what does pepsin do
digests proteins
357
where are proton pumps located in stomach
parietal cells
358
what is echanged for for H in parietal cells proton pump
K
359
what do endochromattin cells produce
histamine, then attaches to H2 receptor on parietal cell, stimulates HCl production
360
what does gastrin do
goes to blood stream, attaches to G receptor on parietal cell to stimulate HCL
also attaches to endochromattin cell G receptor which stimulates histamine and thus HCL
361
what nuerotransmitter from vagus nerve stimulates endochromattin cell
Ach
362
what are the two areas of affect of Vagus nerve in stomach
endochromattin cell
muscarinic receptor on parietal cell
363
what are sources of HCl production/stimulation
positive feedback
vagus nerve histamine
proton pump in parietal cell
endochromattin cell histamin
G cell gastrin release
364
what are sources of inhibiting HCl
-D cells-somatostatin
-arachidonic acid producing prostaglandins
365
where does somastain from D cells have affects
ties up gastrin in blood stream
ties up G receptors on parietal cells
negative impact on parietal cells
366
what do prostaglandins do to parietal cell
decrease HCl
367
what do prostaglandins do to mucus cells
increased mucus and bicarb production
368
how do antacids work
neutralize stomach acid, limited affect
369
How do H2 receptor antagonists work? (somatadin)
-Decreases gastric acid secretion by blocking H2 receptors on parietal cells of stomach
-not long lasting
370
How do PPIs work? (prilosec)
inhibit the H+/K+ proton pump stomach parietal cells.
371
how do nsaids affect stomach acid
inhibit cos from arachadonic acid, so no prostaglandin, so no prostaglandins to stoc HCl, produce bicarb, and increase mucous
372
what peptide/protein hormones does thyroid produce
calcitonin
373
what peptide/protein hormones does pancreas produce
insulin, glucagon, somatostatin
374
what peptide/protein hormones does liver produce
somatomedin (IGF-1)
375
what peptide/protein hormones does parathyroid produce
PTH
376
what peptide/protein hormones does placenta produce
HCGs
HCS
HPL
377
what peptide/protein hormones does kidney. produce
renin
378
what peptide/protein hormones does heart produce
ANP
379
what peptide/protein hormones does GI tract produce
gastrin
CCK
secretin
GIP
somatostatin
GLP-1
380
what peptide/protein hormones does adipocytes produce
leptin
381
what peptide/protein hormones does anterior pituitary produce
ACTH,
TSH,
FSH,
LH,
PRL,
GH
382
what peptide/protein hormones does does hypothalamus produce
TRH,
GnRH,
CRH,
GHRH,
somatostatin
383
what peptide/protein hormones does posterior pituitary produce
oxytocin
ADH
