Exam 3: GI Flashcards
what is mucus composed of
mainly water
electrolytes
glycoproteins
what are properties of mucus
adherent-sticks to food
body-coats well
low resistance-lubrication
self adherence-sticks together
resistant to digestion
buffering capacity
what shape must food be to swallow
bolus
why does mucus need to be resistant to digestion and have buffering capacity
can tolerate the HCl and low ph of stomach
what are the two types of saliva
serous
mucous
what is contained in serous saliva
watery secretion
contains a-amylase
what does amylase digest
carbs
what is contained in mucous saliva
mucin
can humans digest cellulose
no
how much saliva is secreted a day
800-1500 ml/day
what is the maximum rate of saliva secretion
4ml/min
what kind of saliva does the parotid gland secrete
serous
what kind of saliva does the submandibular gland secrete
mucous and serous
what kind of saliva does the sublingual gland secrete
mucous/serous
what kind of saliva does the buccal gland secrete
mucous
what two glands make up 90% of saliva secretion
parotid and submandibular
what is the cephalic phase of digestion
mouth watering in response to seeing or smelling food
(prepares)
what nerve controls the cephalic phase of digestion
vagus
what happens in the gastric phase of digestion
initiates digestion through stimulating:
pepcin
chief cells
parietal cells
mucous cells
what happens in the intestinal phase of digestion
absorption
nervous and hormonal mechanisms
what are the three phases of digestion
cephalic
gastric
intestinal
why doesnt the stomach digest itself
gastric mucosal barrier/mucous cells
what is the anatomical portion of the gastric mucosal barrier
cell membranes and tight junctions between cells
what is the physiological portion of the gastric mucosal barrier
diffused H ions are transported back to lumen
what is found in 95% of patients with duodenal ulcers
H pylori
what is found in 100% of gastric ulcers (when alcohol asa, NSAIDs are eliminated)
H pylori
what are propterties of H pylori
gram -
high urease activity
can withstand acid
NH4 damages epithelial cells in GU
increases acid secretion
what are risk factors for ulcers
NSAIDS
H. pylori
alcohol
how do NSIADS affect stomach
increased acid production
decreased mucous production
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
does pepcin digest protein?
no, it digests collagen which binds muscles together
what allows acidic chyme to be neurtalized
bicarb from pancreas
how does the pancreas help break down macromolecules
secretes digestive enzymes for all food types
what are the grape like structures in the pancreas that store and secrete digestive enzymes
acini
what secretes bicarb form the pancreas
ducts
what receives secretion from the acini in the pancreas
intercalated ducts
what receives the fluid from intercalated ducts in pancreas
intralobular ducts
what do islets of langerham do
release insulin and glucagon into the blood stream
what type of enzymes are prodouced in islets of langerham (end or exo)
endocrine portion
what kind of enzymes (endo or exo) are produced in the acini
exocrine
what lines the ducts in the pancreas
chloride channel, opens and allows sodium bicarb to escape
what do the chloride ducts in the pancreas transport
bicarb
what is produced in pancreas
insulin and glucagon
amylase, lipase
tripsonigen
chymotrypsin
what two pancreatic enzymes cleave proteins into polypeptides
trypsin
chymotrypsin
what kind of enzymes are trypsin, chymotripsin, carboxypeptidase
proteolytic enzymes
what three enzymes breakdown proteins
trypsin,
chymotripsin,
carboxypeptidase
what cleaves polypeptides into amino acids
carboxypeptidase
what keeps the proteolytic enzymes from eating pancrease
-trypsin inhibitors in cell
-they are all stored and secreted in inactive form
what is the precurser to trypsin
trypsinogen
what breaks down starches and glycogen into disaccharides
pancreatic amylase
what is the precurser to chymotripsin
chymotrypsinogen
what is the precurser to carboxypeptidase
procarboxypeptidase
what is the only luminal enzyme for carb digestion
amylase
all enzymes are secreted in ______ enzyme secretion must be decreased 10-15% of normal to cause problems
excess
what are all foods broken down into
proteins
carbs
fats
what breaks fats into fatty acids and monoglycerides
pancreatic lipase
what breaks phospholipids in fatty acids
phospholipase
when you break down fats they are too large to go into blood stream, so what absorbs them
lactiles, into lymph, into venous system
what breaks down cholesterol esters in fatty acids
cholesterol esterase
What converts trypsinogen to trypsin?
enterokinase
where is trypsin inhibitor made
inside the pancreas so trypsin in pancreas is still unable to cause harm
what happens when tripsin inhibitor in inhibited or neutralized
pancreatitis
where is enterokinase located
located in intestinal mucosa
where else is trypisin inhibitor located
in lungs
what ph does bicarb neutralize chyme to
7-8
what induces bicarb release from pancreas
secretin
where is secretin produced
S cells of duodenem
how does secretin affect liver
increase bile production in liver
how does secretin affect stomach
decreases HCl acid production by parietal cells
what produces HCl acid in stomach
parietal cells
what increases the rate of exchange between cl and bicarb in pancreas
secretin
what stimulates the secretion of fluid and HCO3 in the duodenum
the amount of acid entering the duodenum
what stimulates the sescretion of enzymes in the deuodenum
amount of fat and proteins entering the duodenum (not carbohydrates)
what stimulates the release of cholesystokinen
fat and aminio acids
at what pH is secretin released
<4.5
when is the max amount of secretin released
pH <3
during meals pH is rarely less than
3.5 or 4
what does Brunners glands secrete
alkaline mucus
what does the crypts of lieberkuhn do
secretes water like fluid (1800 ml day)
where are crypts of lieberkhun located
bottom of interstitial villi
why does interstitial villli regrow quickly
crypts of lieberkuhn contain lots of stem cells
are their crypts of lieberkuhn in large instestine?
yes, not there are no villi or enzyme, so mostly secrete alkaline mucous
what is present in all the digestive tract and alls movement through tract
alkaline mucous
what increases mucous production in Gi tract
parasympathetic stimulation
what is the major function of the colon
absorption of water, forms stool
what stimulates bile release
cholecystokinin responding to lipids
What does cholecystokinin do?
its a messenger,
does not do anything on its own,
tell the gall bladder to release bile
what is hydrolysis in digestion
adding water to nutrients so they can be absorbed in small intestines
what do carbohydrates break down into
monosaccharides
what are proteins broken down into
small peptides and amino acids
What are fats broken down into?
monoglycerides and fatty acids
where does luminial/cavital digestion occur
in lumen of GI tract
what carries out luminal digestion
enzymes from salivary glands, stomach, pancreas
where does contact/membrane digestion occur
in the brush borders of GI tracts
what carries out contact digestion
enzymes on brush border of enterocytes
what enzymes are in the salivary glands
amyliase
lingual lipase
what enzymes are in the stomach
pepsin
what enzymes are in the pancrease
amylase
trypsin
chymotripsin
carboxypeptidase
elastase
lipase-colipase
phospholipase
cholesterol esterase
what enzymes are in the intestinal mucosa
enterokinase
sucrase, maltase, lactase, trehalase, extrinase
amino-oligopeptidase
dipeptidase
what enzymes are intracellular
dipeptidase
tripeptidase
what gets absorbed in the stomach
ethanol, NSAIDs, aspirin
what gets absorbed in the duodenum and jejjunum
nutrients,
vitamins,
various ions,
water,
electrolytes
what gets absrobed in the ileum
bile salts
vitamin B12
what gets absorbed in the colon
water and electrolytes
what gets absorbed in the rectum
drugs such as steroids and salicylates
what does B12 do
RBCs
how many layers do nutrients pass through to get to blood
8 layers
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
where does lactose (milk) and sucrose digestion occur
only brush border
what is lactose made up of
galactose and glucose
What is sucrose made of?
glucose and fructose
can you absorb lactose and sucrose? or maltose and glu-polymers?
NO
80% of all carbs are absorbed as
glucose
10-fructose
10-galactose
What is maltose/glu-polymers made of?
multiple glucose molecules
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)
Proteins are broken down into
peptides and amino acids
what are the steps of lipid digestion
1- emulsified by bile (enterokinin)
2-enzymatic digestion (lipase into fatty acid and glycerides)
most dietary lipid is
neutral fat or triglycerides
what is fat broken down into
fatty acids and glycerol
what are micells
a water-soluble transporter to transport fat for absorption into the lactile
what percentage of fat is broken down into triglycerides
90%
how much fluid enters the body a day from sources
diet -2
saliva- 1
stomach -2
bile -1
pancrease -1
SI -2
where is fluid absorbed
duodenum and jejunum- 4
ilium -3.5
colon -1.4
what is the movement of water inbody
diffusion/osmotic forces
hypotonic chyme results in water
absorption
hypertonic chyme results in water
entering intestines
chyme is usually what tonicity
isotonic
the endocrine system is made up of
anything that makes hormones
what two systems keep us in homogenous state
neuro system
endocrine system
what is the bodies quick reaction to homogenous state
neuro
what is the bodies slow and long lasting reaction to homogenous state
endocrine system
endocrine system uses the ________ system to have affect on body
venous
where does the paracrine system have affect
cell to cell through interstitial fluid
endocrine means it travels in the
blood
neuroendocrine means a _________ stimulates a hormone releases that travels in the _________
neuron
blood
where does autocrine system have effect
cells releases hormone to affect itself
what are the three classes or hormones
peptide/protein hormones
steroid hormones
amine hormones
a substance with <100 amino acids is a
peptide/polypeptide
a substance with >100 amino acids is a
protein
what glands and tissues create peptide/protien hormones
hypothalmus
anteiror pituitiary
posterior pituitary
thyroid
pancreas
liver
parathyroid
placenta
kidney
heart
GI tract
adipocyte
how do protein/peptide hormones work
there is a receptor on the surface of the target cell
what hormones work on a receptor of the target cell
peptide/proteins
amines
steroids are made up of
lipids
steroids have their affect by
entering the cell and working in cytoplasm
what organs/glands make steroid hormones
adrenal cortex
testes
ovaries
corpus luteum
placenta
kidney
What steroid hormones does the adrenal cortex secrete?
cortisol
aldosterone
androgens
what steroid hormones do the testes secrete
testosterone
what steroid hormones does the ovaries, corpus luteum, and placenta secrete
estrogens, progesterone
what steroid hormones does kidney secrete
1,25 dihydroxycholecalciferol
what glands/organs secrete amine hormones
hypothalamus
thyroid
adrenal medulla
what amine hormone does the hypothaomus secrete
dopamine
what does dopamine do
neurotransmitter
movement of spinae eretae
motivation
emotion/feel good
what amine hormones does the thyroid secrete
T3 T4
what amine hormone does the adrenal medulla secrete
NE
EPI
where do all amine hormones come from
tyrosine
what is an example of a transport protein
albumin
what creates a positive feedback
levels too low, tell you to secrete hormone
what creates a negative feedback
levels too low, tell you to stop secreting hormone
Where does the pituitary gland sit?
sella tursica
which part of the pituitary is vascular driven
anterior
which part of the pituitary is neurologically driven
posterior
adeno means
glandular
antidiuretic hormone (ADH) is also called
vasopressin
what is released when the posterior pituitary is stimulated
oxytocin and vasopressin (ADH)
what is secreted from the anterior pituitary
growth hormone
adrenocorticotrophic hormone
TSH
FSH, LH
melanocyte stimulating hormone
prolactin
what does oxytocin do
Milk letdown and uterine contractions
What does ADH do?
increases NaCl and H20 resorption in kidney increased intravascular volume
vasoconstriction
what connects the hypothalamus to the pituitary gland
portal system
what must be present to cause a release a hormone from anterior pituitary
release hormone in hypothalamus, goes through portal system to anterior pituitary
what does GHRH release
GH
what does GnRH release
LH
FSH
What does PRH stimulate?
prolactin
What does CRH stimulate?
ACTH
What does TRH stimulate?
TSH
what does growth hormone do to liver
IGFs
what does FSH and LH do to testes/ovaries
testoserone/estradiol/progesterone production
what does prolactin do to mammary gland
produce milk
what does ACTH do yo adrenal gland
cortisol
what does TSH do to thyroid
release T3 T4
what three things is food broken down into
fats
carbs
proteins
fats are broken down into
fatty acids and glycerol
proteins are broken down into
amino acids
Carbs are broken down into
monosaccharides
what are the segments of the GI tract
mouth
pharynx
esophagus
stomach
small intestine
large intestine
sphincters
what does the liver produce for digestion
produces bile
what does bile do
emulsifies fat
what does the gall bladder do for digestion
stores bile
what tells gall bladder to release bile
cholecystokinins
What are the endocrine functions of the pancreas?
insulin
glucagon
what does an exocrine gland do
Secrete products into ducts, tears and sweat
what does a paracrin gland do
releases hormones to affect neighboring cells
what does an endocrine gland do
releases hormone to bloodstream
What are the exocrine functions of the pancreas?
amylase (carbs)
lipase (fats)
tripsan (proteins)
what does the pancreas release to neutralize the gastric pH
bicarb
why does pancreatits lead to duodenal ulcers
pancreas doesnt creat bicarb
what do parotid and salivary glands secrete for digestion (and submandibular?)
alpha-amylase to digest carbs
anatomy review
what is the outside layer of the GI tract
serosa
Gi tract muscle shortens the tube (peristalsis)
longitudinal
what Gi tract muscle creates intestinal tone
circular muscle
what is the inside layer of the Gi tract
mucosa
gut wall layers
what is the enteric nervous system of the GI tract
myenteric plexus
what are the two nervous systems of the GI tract
enteric
autonomic
what is the role of the enteric nervous system of the GI tract
create intestinal tone
what is the role of the mesentery
Attaches to abd wall
conduit for blood supply
which GI nerve plexus is in between longitudinal and circular muscle
myenteric nerve plexus
what three things regulate the Gi tract
GI peptides
nerves
smooth muscle
all Gi hormones are ________
peptides
what is a VIP
vasoactive intestinal peptide (nitrous oxide)
can the ENS function without the ANS
yes
what NS in the Gi tract creates visceral tone
ENS (enteric nervous system)
what is the effect of exciting a sphincter
closes
what stimulates the release of gastrin
protein
distention
nervous system
What inhibits release of gastrin?
acid
Where is gastrin secreted?
G cells in the antrum of the stomach, duodenum, and jejunum
what is the action of gastrin
stimulates gastric acid secretion and mucosal growth
what stimulates the release of cholecystokinin
proteins
fats
acids
where is cholecystokinin released
I cells of the duodenum, jejunum, and ileum
what is the action of cholecystokinin
stimulates:
pancreatic enzyme secretion
pancreatic bicarb secretion
gallbladder contraction
growth of the exocrine pancreas
inhibits:
gastric emptying
what stimulates secretin release
acid
fat
what is the site of aciton of secretin
S cells of duodenum, jejunum and ileum
what are the actions of secretin
stimulates:
- pepsin secretion
- pancreatic bicarbonate secretion
- biliary bicarbonate secretion
- growth of exocrine pancreas
inhibits:
- gastric acid secretion
what stimulates the release of gastric inhibitory peptide
proteins
fats
carbs
what is the site of secretion of Gastric inhibitory peptide
K cells of duodenum and jejunum
what are the actions of gastric inhibitory peptide
stimulates insulin release,
inhibits gastric acid secretion
what stimulates the secretion of motilin
Fat, acid, nerve
what is the site of secretion of motilin
M cells of duodenum and jejunum
what is the action of Motilin
stimulates gastric motility and intestinal motility
T/F most ulcers are caused by excess HCl
F, its from decreased mucous
what breaks down protein
pepsin
what stimulates the secretion of pepsin
protein ingestion/secretin
what breaks down fats
lipase and bile
what is the location of the enteric NS
gut wall from esophagus to anus
if sphincter is inhibited it then _______
opens
what nervous systems exhibit extrinsic control of the GI tract
parasympathetic
sympathetic
what are the two parts of the enteric nervous system
myenteric plexus
submucosal plexus
what is the function of the myenteric plexus
controls GI motility
what are the stimulatory influences of the myenteric plexus
tone
contraction frequency/intensitry (peristalsis)
sympathetic nerves in the bowel are _______ ganglionic
post
what are the inhibitory influences of the myenteric plexus
decreased sphincter tone (pyloric, ileocecal, LES)
where is the submucosal plexus located
mucosal layer from esophagus to anus
what is the function of the submucosal plexus
Secretion
Absorption
Contraction of muscularis mucosa
what is the parasympathetic innervation for the first half of the gut
vagus nerve
what is the parasympathetic innervation for the second half of the gut
pelvic nerve
Where do parasympathetic nerves originate?
pons and sacrum
parasympathetic have a _________ postganglionic
short
where do the sympathetic nerves for the GI tract come from
T5-L2
how does exciting parasympathetic affect GI
increased digestion
what kind of influence does the sympathetic have on GI
inhibitory
What are excitatory neurotransmitters of the Gi tract
acetylcholine,
substance P,
serotonin
what are the inhibitory neurotransmitters of the GI tract
VIP
NO
what stimulates sensory afferent neurons in the GI
distension of Gut wall
irritation of gut mucosa
specific chemical stimuli
what is function of gap junctions in Gi smooth muscle
helps cells move as one for peristalsis
what is a syncytium
When cells are connected together, as by gap junctions, and act as one large cell.
what are slow waves
-rhythmical changes in membrane potential caused by variations in sodium conductance
-increased membrane potentials, but not to threshold
What is a spike potential/wave
-occurs when slow waves reach threshold
-cause SM to contract
-Ca enters to cause contraction
slow waves are controlled by what ion
Na
spike waves are controlled by what ion
Ca
what is the propulsive movement of the GI tract
peristalsis
orad is towards
mouth
caudad is to
tail
what muscle do peristalsis
circular and longitudinal muscles
what stimuli increase peristalsis
1-distension (orad contraction with downstream receptive relaxation)
2-irritation of gut epithelium
3- parasympathetic nervous system
how does atropine affect peristalsis
decreases, blocks Ach receptors
what is another name for portal circulation
Hepatic
where does blood from stomach, intestines go first
liver (portal vein)
portal circulation
what three branches of the aorta supply the Gi
celiac trunk
superior mesenteric
inferior mesenteric
how does a meal affect GI blood flow
increases
in villi _______% of oxygen is shunted from artery to vein
what is this called
80%
countercurrent oxygen loss
what happens to villi when there is circulatory shock, decreased CO, hypotension, mechanical obstruction
avascular necrosis to tip of villi, sloughs off
what absorbs fats into the lymph system
central lacteal in villi
how does fat get into blood stream from Gi tract
lymph system
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
which nerve controls chewing
cranial nerve 5, trigeminal (maxillary and mandibular branches)
what stimulates the swallow reflex
bolus in back of mouth
what are the three stages of swallowing
voluntary stage,
pharyngeal stage,
esophageal stage
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
where does swallowing reflex come from
pons
what is the continuation of pharyngeal peristalsis in the esophagus
primary peristalsis
what happens in esophagus after primary peristalsis
secondary peristalsis
what induces secondary peristalsis
distension
the upper 1/3 of esophagus is _________- muscle
striated
the lower 2/3 of esophagus is _______ muscle
smooth
how does surgery affect elasticity of esophagus
decreases
what keeps air from entering esophagus
upper esophageal sphincter
what keeps acid from refluxing into esophagus
lower esophageal sphincter
what are the layers of the stomach muscles
longitudinal
circular
oblique
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)
what ph does chyme have to be for enzyme function
7
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
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
activation of intestinal receptors __________ gastric emptying
decreases
what stimulates intestinal mucosa receptors
high or low osmolarity
acids
fats
proteins
what do fats and proteins trigger for gastric emptying
CCK (cholecystokinin) release increases gastric distensibility which decreases gastric emptying
what do acids trigger for gastric emptying
decreases via intrinsic neural reflex
what are the two types of movement in the small intestines
peristalsis
segmentation
what movement is a propulsive movement
peristalsis
what movement is a mixing movement
segmentation
what sweeps undigested residue toward colon to maintain low bacteria counts in upper intestine
migrating motility complexes
what is the most coordinated, rapid peristalsis
migrating motility complexes
what type of intestinal movement happens between meals
migrating motility complexes
what mediates migrating motility complexes
motlin
ENS
what mediates the peristaltic reflex
ENS
what mediates the intestino-intestinal reflex
extrinsic nerves
what stimulates gastroileal reflex
meal
ileocecal sphincter relaxes
ileal peristalsis increases
spike potentials and thus contractions depends of what two types of input
neural and hormonal
What does motilin do?
mediates migratory motor complexes
what do serotonin and prostaglandins do
stimulate motility (large quantities in small intestines)
what two structures are in the ileocecal junction
valve-prevent backflow
sphincter-regulates movement from ileum to cecum
what are the functions of the large intestines
-mixes chyme-enhanvces fluid and electrolyte absorption (haustra)
-propels fecal material (mass movement)
(more/less) water is reabsorbed in small intestines than in the colon
more
what muscles are in the large intestines
-longitudinal smooth muscle
-circular smooth muscle
-internal anal sphincter
-external anal sphincter
-hausta
what is the internal anal sphincter made of
circular muscle
what is the external anal sphincter made of
striated muscle
where is myenteric plexus concentrated in large intestines
teneae coli
where does large intestines receive parasympathetic innervatgion
vagus in proximal colon
pelvic nerves S2-s4 in distal colon, rectum/anus
what innervates in external anal sphincter
pudendal nerve
what is the purpose of haustral contractions
mixing movements facilitate fluid and electrolyte absorption
what is the propulsive movement of the large intestines
mass movement
when do mass movements occur
after meals
reflexes like gastrocolic reflex and duodenocolic reflex
what are the three levels of control of defecation
intrinsic reflex
spinal cord reflex
involvement of higher centers
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
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
what is the higher centers defecation reflex
valsava maneuver
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)
what does the peristaltic reflex do
bowel stretch
proximal contraction
distal relaxation
what does the enterogastric reflex do
from duodenum to regulate gastric emtpying
what does the gastroileal reflex do
gastric distension relaxes ileocecal sphincter
what does the intestino-intestinal reflex do
over distension or injury of bowel segment causes bowel to relax
what does gastro and duodenocolic reflexes do
distention of stomach/duodenum initiates mass movement
what initiates the defecation reflex
rectal distension initiates defecation
Where does bilirubin come from?
It comes from the breakdown of heme, a part of the hemoglobin.
What is erythropoiesis?
production of red blood cells in marrow
how long to rbcs live
120 days
what three areas dispose of RBCs
spleen
liver
marrow
what breaks down RBC
macrophages
what are RBCs broken down into
heme and globin
What is heme broken down into?
iron and bilirubin
bilirubin is___________ soluble
lipid
unconjugated bilirubin binds with ___________ to go through blood stream and make it non-toxic
albumin
bilirubin enters the liver as
unconjugated
what cells in the liver break down RBCs
kupffer cells, also form unconjugated bilirubin
what substance in the liver changes bilirubin to conjugated form
glucaronic acid
conjugated bilirubin is ___________ soluble
water
what happens when bacteria in gut attacks bilirubin
changes it back to unconjugated bilirubin (10%)
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
what gives stool its brown color
conjugated bilirubin
what is another name for parietal cells
oxytonic
what produces mucus in stomach
mucus cells
what produces gastrin in stomach
G cells
what produces somatostatin in stomach
D cells
what creates HCl in stomach
parietal cells
what produces pepsinogen in stomach
chief cells
What converts pepsinogen to pepsin?
HCl
what does pepsin do
digests proteins
where are proton pumps located in stomach
parietal cells
what is echanged for for H in parietal cells proton pump
K
what do endochromattin cells produce
histamine, then attaches to H2 receptor on parietal cell, stimulates HCl production
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
what nuerotransmitter from vagus nerve stimulates endochromattin cell
Ach
what are the two areas of affect of Vagus nerve in stomach
endochromattin cell
muscarinic receptor on parietal cell
what are sources of HCl production/stimulation
positive feedback
vagus nerve histamine
proton pump in parietal cell
endochromattin cell histamin
G cell gastrin release
what are sources of inhibiting HCl
-D cells-somatostatin
-arachidonic acid producing prostaglandins
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
what do prostaglandins do to parietal cell
decrease HCl
what do prostaglandins do to mucus cells
increased mucus and bicarb production
how do antacids work
neutralize stomach acid, limited affect
How do H2 receptor antagonists work? (somatadin)
-Decreases gastric acid secretion by blocking H2 receptors on parietal cells of stomach
-not long lasting
How do PPIs work? (prilosec)
inhibit the H+/K+ proton pump stomach parietal cells.
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
what peptide/protein hormones does thyroid produce
calcitonin
what peptide/protein hormones does pancreas produce
insulin, glucagon, somatostatin
what peptide/protein hormones does liver produce
somatomedin (IGF-1)
what peptide/protein hormones does parathyroid produce
PTH
what peptide/protein hormones does placenta produce
HCGs
HCS
HPL
what peptide/protein hormones does kidney. produce
renin
what peptide/protein hormones does heart produce
ANP
what peptide/protein hormones does GI tract produce
gastrin
CCK
secretin
GIP
somatostatin
GLP-1
what peptide/protein hormones does adipocytes produce
leptin
what peptide/protein hormones does anterior pituitary produce
ACTH,
TSH,
FSH,
LH,
PRL,
GH
what peptide/protein hormones does does hypothalamus produce
TRH,
GnRH,
CRH,
GHRH,
somatostatin
what peptide/protein hormones does posterior pituitary produce
oxytocin
ADH
