What is the double layer extension of peritoneum that descends distally over the stomach, duodenum & transverse colon
Greater omentum
What is considered to be the abd policeman & is the site of metastasis
greater omentum
what does the lesser omentum cover
stomach
duodenum
liver
What is the double layer extension of the peritoneum that covers the stomach, duodenum & liver
lesser omentum
What is the double layer fold of peritoneum that connects the small intestine to abd wall posteriorly (retroperitoneum)
mesentery
What is the arterial blood supply for the mesentery
aorta
sup & inf mesenteric a
Does the mesentery connect organs together
yes
What are the functions of the alimentary canal
GI tract
mout to anus
breaks down & absorbs nutrients
expels indigestibles
protects body from fluid loss
prevents toxic substances from entering body
under control of nervous & hormonal systems
Where is the approximate location for the diaphragm
superor boundary of the abd cavity
inferior boundary of the thoracic cavity
What are the 3 openings for the diaphragm
aorta=t12
esophagus=t10
IVC=t8
What are the 4 muscles of mastication/chewing
temporalis
masseter
lat & med pterygoid
What do incisors do
cut
what do molars do
grind
what is the pH of the oral cavity
7
What is the purpose of chewing
to increase the total surface area that digestive enzymes break down
What is another name for swallowing & what are the 3 stages
deglutition
vol stage
pharyngeal stage
esophageal stage
What stage is referring to when food is ready to swallow that is voluntarily squeezed post to pharynx with the tongue pressure upward/backward against palate
voluntary stage
When do the swallowing stages become automatic
after the voluntary stage
Explain what happens during the pharyngeal stage of swallowing
the soft palate will close with the pharyngeal muscles pulling together. The vocal chords & epiglottis will close with the larynx moving upward & the upper esophagus relaxes. Finally, the pharynx muscles contract up/down to initiate peristalsis
Where is the swallowing center located
medulla
lower pons
What CN's are involved with the sensory center
5
9
What is the area of the swallowing receptor area that is found all over the pharynx with a great amount of sensitivity on tonsillar pillars
sensory center
What interrupts respiration to allow swallowing to proceed & is responsible for the gag reflex if not swallowed
swallowing center
how long is the esophagus
25cm lenght
2cm dia
where does the esophagus go
thoracic & abdominal
What does the esophagus emerge through
diaphragm at the vagus nerve at the level of t10
what type of hernia is associated with the esophagus
hiatal
What are the stages involved with the esophageal stage
primary peristalis=initiates wave
2nd peristalsis=myenteric nerve plexus
relaxation of stomach=precedes peristalsis
The pharynx and upper 1/3 esophagus are voluntary & made up of what type of muscle
striated
The lower 2/3 esophagus is involuntary & made up of what type of muscle
smooth
T/F If the vagus nerve is cut, peristalis can't continue
F=it can continue
What are the functions of the lower esophageal sphincter (LES)
prevents acid reflux
increased abd pressure=caves lower portion of esophagus inward
Where is the LES located
esophageal valve 3cm above cardia
Is the LES normally tonically constricted
yes
What is meant by the term achalasia
LES doesn't relax
What is the GI tract/wall consist of
4 layer hollow tube
hollow area=lumen
mucosa
submucosa
muscularis
serosa
What is the innermost layer of the gi tract that consists of epithelial lining, lamina propria & muscularis musosae
mucosa
what does the lamina propria consist of
conn tissue
lymphatics
BL vessels
What is similiar to the mucosa but has denser conn tissue & nerves
submucosa
This layer of the gi tract wall has 2 layers smooth muscle, constricts gi tract in dia & length; has a circular inner most & longitudinal outer most
muscularis
Which layer of the gi wall is innervated by the myenteric nerve plexus interspeersed throughout
muscularis
This layer of the gi wall is a thin layer conn tissue that has blood vessels, lymphatics, fat, squamous epithelial cells
serosa
The GI wall cell membrane has what
smooth muscle
epithelial cells=enterocytes
enterocyte cell membrane
What makes up the enterocyte cell membrane
luminal (apical) vs basolateral
luminal mem faces hollow lumen surface
basolat mem faces lamina propria & BL supply
What are the digestive factors excreted across luminal membrane
foodstuffs absorbed via fac diffusion or AT
occurs across luminal then basolat mem
moves into blood stream for tissue distribution
What does depolarization do to the gi wall cell membrane
excites
What are the factors that depolarize cell membrane
muscle stretching
ACh stimulation
PNS release of ACh
Specific gi hormone stimulation
The PNS release of ACh will promote what in the gi wall CM
motility
secretion
sphincter relaxation
what does hyperpolarization do to the gi wall CM
inhibits
What are the factors that hyperpolarize CM
NE & E stimulation
stimulation of SNS
anticholinergic drugs
The SNS stimulation has what effects on the gi wall CM
inhibits motility
secretions
constricts sphincters
What are the two types of smooth muscle contractions in the GI
rhythmic
tonic
This type of smooth musc contraction is the most common in GI
rhythimic
This type of sm musc contr is continous & caused by partial depolarization
tonic
The continous tonic contraction of the GI has what effects
increase/decrease in intensity
lasts several min or hrs
What type of sm musc contr is determined by frequency of slow waves of smooth musc mem pot
rhythmic
how many rhythmic contractions occur in each min
3-12
Slow waves are thought to come from what
Na/K pump that don't normally cause contraction
how are smooth musc contraction happen
spikes in potential that allow ca ions to enter muscle fibers
How does gi smooth musc fiber potential differ from that of nerve fiber potential
NF=rapid entry of na ions
GI=lrg#ca ions, small na ions via ca/na ch (slow) & ca=contraction
What are the 2 intramural plexus
myenteric=outer
subucosal=inner
What is the intramural plexus
neural control of GI fx
ENS
located in gut wall
2 plexuses
What is another name for the auerbach's plexus
myenteric
Which plexus is btwn circular & longitudinal musc layers of muscularis
myenteric
Which plexus controls smooth muscle coordinated contraction & relaxation of gi tract (peristalsis)
myenteric
What is the purpose of peristalsis
maintains tone
increases intensity of contraction
increses rate of rhythm
increases velocity of vaves of conduction
Which plexus secretes vasocative polypeptides
myenteric
What is meissner's plexus
submucosal plexus
This plexus is btwn muscularis & submucosa that is involved with local intestinal secretion, absorption & contraction of submucosal smooth muscle
submucosal/meissner's
What is a excitatory NT
Ach
What is an inhibitory NT
NE & E
What are some mixed NT's
ATP
serotonin
cholycytokinin
Sub P
VIP
somatostatin
leu-enkephalin
metenkephalin
bombesin
What is the anutonomic control of the GI tract
connects SP/BS to MP & Sub P via vagus & peliv nerves
PNS=pregang-release Ach
SNS=postgangl
What are the 2 division of the PNS innervation
cranial
sacral
The cranial division is supported by the vagus nerve that innervates
upper esophagus to transverse colon
The sacral divisoin is supported by pelvic nervies that inntervates
splenich flexure of colon to internal anal sphincter
where does the sympathetic chain orginate for sympathetic innervation
SP btwn T5-L2 & lies laterally
What are the two outlying ganglia for the sympathetic innervation
celiac
mesenteric
What do the sympathtic nerve endings secrete
NE that have a direct effect to inhibit smooth muscle
T/F Indirect effect is through the ENS
T
The afferent sensory nerve fibers have what types of signals transmitted
excitation/inhibition
what are the afferent stimulants
irritation of gut sm musc
excessive distension of gut
presence of specific chemical substances
where do afferent sensory nerve fibers terminate
ENS
Afferent sensory nerve fibers are cell bodies in ENS but axons as they extend through ANS to the what 2 prevertebral ganglia
mesenteric
hypogastric
What are the other cell bodies in dorsal SP Cord or cranial ganglia
vagus nerve as 80% is afferent
What are the 3 types of GI reflexes that are essential for gut control
gastrocolonic
enterogastric
colonoileal
The Gi reflexes are located where
ENS or gut wall
prevertebral ganglia
Sp cord/BS
What does gastrin do
promotes stomach emptying
Explain cholecystokinin
T-cell secretion in the duodenum, jejunum in response to fats, fatty acids, monoglyceride breakdown that increases contractility & decreases motility
Explain Secretin
S-cell secretion in the duodenum in response to emptying of acidic gastric juices with a mild inhibitory effect
Explain GIP
in response to fatty & amino acids, carbos that decreases motility & slows gastric emptying
Peristalis is always what to what
oral to anal
what is the myenteric reflex
peristaltic reflex
what is the law of the gut
peristalsis always oral to anal
myenteric reflex=peristaltic reflex
receptive relaxation
All blood through the gut, spleen, pancrease flows into the liver via what vein
portal vein
What is in the liver
liver sinusoids
recticuloendothelial cells line sinusoids
removes toxins
hepatic cells
fats not absorbed portal circulation
what are the principal paranchymal cells of liver
hepatic cells
how are fats absorbed if not through portal circulation
intestinal lymphatics then into circulating blood supply
which artery supplies the stomach
celiac
which artery supplies the walls of intestines
mesenteric (arching arterial system)
which arteries circle the gut
villus
Which arteries penetrate intestinal wall & spread via looping capillaries along musc bundles into intestinal villi into submucosal vessels
smaller arteries
where are the peptide hormones released from
gut mucosa
What are the vasodilators
CCK
VIP
gastrin
secretin
kinins
What secretes kinins
gut wall
What increases blood flow & secretions to the gut
PNS innervation
What does sympathetic do
vasoconstricts
Cell death potential in what
shock
This type of shock is of all body's vital tissues at risk for cell death due to lack of blood flow to the brain or heart
circulatory shock
Splanchinic blood flow is decreased for many hrs via sympathetic stimulation for what type of shock
circulatory shock
Explain hemorrhagic shock
Under control of sympathetic stimulation that has a strong vasoconstriction of intestinal mesenteric veins that decreases vol of veins, displaces lrg amts blood to other parts for circulation with 200 to 400ml extra blood sustain gen circulation
What are the functions of the stomach
mixes food w/secretions
can hold up to 2L
slows emptying of chyme at optimal rate for digestion
vagovagal reflex
sm amt fat absorption
what is the pH of the stomach
1
What are some symptoms of stomach cancer
postprandial, epigastric pain
early saitiety
anemia
obstruction
where is stomach cancer most prevelent
japan with a 5-20% survival rate for about 5 to 8mo's
this sphincter is muscular that prevents passage of food & emptying is triggered by gastrin or increase food volume
pyloric sphincter
how long is the small intestine
6 to 7 meters
What are the areas of the sm intestine
duodenum
jejunum
ileum
where is the sm I
retroperitoneal
plicae circularis
Explain the small intestine mesentery
begins at the ligament of treitz ending at the ileocecal junction that prevents twisting of the gut
Explain the duodenum
it is 25 cm in length with a C shaped: ampulla/superior, descending, inferior, ascending
How does the duodenum inhibit stomach emptying
throught the enterogastric reflex located in the prevertebral ganglia controlled by vagus to brain stem
What inhibits pyloric pump & increases tone of pyloric sphincter
duodenum
what is the hormonal feedback for the duodenum
inhibits gastric emptying
hormone production in excess quantities of fat or acidic chyme
secretin, CCK, GIP
Insulin release
where is the jejunum
mostly LUQ
Explain the jejunum
large dia with a thicker wall that is more vascular with stria that lakcs peyer's patches
where is the ileum
mostly RLQ
Explain the Ileum
smaller diamter with a thinner wall w/mesenteric fat. The terminal ileum connects to cecum with it ending at the ileocecal valve
This is a valve that prevents reflux & is a flap/orifice into colon
ileocecal valve
Which valve is an appendix attachement point
ileocecal valve just follow teniae colo to end point
What is meckles diverticulum
w/in 40 cm of ileocecal valve
intussusception/obstruction
inflammation/ulceration/hemorrhage
what type of ulcer can erode into arteries
posterior
what type of ulcer can erode into peritoneal cavity
anterior
Helicobacter pylori can cause what
ulcers
what can inhibit gastric cells in ulcers
PPI
how can ulcers have a decreased incidence
H2 blocker
what are the 4 types of contractions
mixing
propulsive movements
peristaltic rush
villi contractions
explain mixing contractions
they are different in various areas of gi tract
local intermittent constrictive contractions
chop shear contents to mix
occurs 5-30sec every few cm
What is a propulsive contractions
peristalis
Explain propulsive contractions
they are propulsive mvmts that is stimulated with gut distenstion that causes chyme to move analward & is very slow & weak (1cm/min) takes 3-5hrs to pass from pyloris to ileocecal valve
This is a powerful rapid peristaltic contraction that travels long distances w/in minutes in small I
peristaltic rush
what sweeps contents into colon quickly
peristaltic rush
what are some of the contents that the peristaltic rush sweeps into colon very quickly
infectious diarrhea
SMI irritation
excessive distention of chyme
what are multiple mucosal folds that increases surface area that contacts chyme
villi
What is responsible for the rate of absorption increasing in response to chyme in SMI
villi
what does chyme contact do to the villi
it milks them
what happens in regards to the lymph flow when the villi fibers shorten-lengthen-shorten
it allows it to flow freely to the central lacteals to lymphatic sys
explain the large intestine or colon
1.5 meters
absorbs fluids/salts
tenia coli
haustra
sluggish mvmt
epiploic appendages
cecum 7 to 9 com dia
What are the parts of the lrg intestine or colon
cecum
asc colon
right colic flexure
transverse colon
splenic flexure
desc colon
sigmoid colon
rectum
where does the descending colon end
teniae coli & this is where the sigmoid colon begins
What are the movements of the colon
mixing
propulsion
reflexes
what are the reflexes associated with the colon
gastrocolic
duodenocolic
defecation
peritonealintestinal
renointestinal
Explain the sigmoid colon
intraperitoneal S-shaped loop, 40 cm in length, rectosigmoid junction & diverticula
how far is the rectosigmoid junction from the anus
15 cm
what is associated with divertcula
diverticulosis
divertculitis
perforation
Mucosa & submucosa herniations through or btwn fibers of colonic muscularis propria
diverticula
what is the presence of multiple diverticula
diverticulosis
What is inflammation of the diverticula
diverticulitis
what is weakness of bowel wall caused by bleeding, ulceration or necrosis
perforation
what are some congential abnormalities of the colon
shortening
redundant colon
what can redundant colon cause
volvulus around the SMA
obstruction
ischemic bowel
mesenteric ischemia
what is the primary fx of the secretory glands in the gi tract
secretes digestive enzymes
secretes mucous
what are the 4 types of glands in the gi tract
mucous glands
crypts of lieberkuhn
tubular glands
complex glands
another name for mucous glands
goblet cells
explain mucous glands
single cell that extrude mucous on epi cells that protects, lubricates & responds to food irritation
This type of gland is in the SMI invaginations of epi into submucosa with deep pits w/specialized secretory glands
crypts of lieberkuhn
this type of gland is in the stomach & upper duodenum that secretes acids & enzymes for breakdown, digestion
deep tubular glands
this type of gland provides secretions of digestion or emulsification of food in salivary glands, pancrease & liver
complex glands
This type of glands are special acinar cells that feed into duct system that empty enzymes into gi tract
salivary glands & pancreas
how does the local epithelial stimulation activate ENS
tactile stimulation
chemical irritation
distenstion of gut wall
All of this will result in an increase secretion of goblet & deep tubular glands
what makes up mucous
h20
electrolytes
glycoproteins
what is the fx of mucous
adheres to food & spreads as a film that coats the gut wall preventing direct contact of food to mucosa. It also causes fecal matter to adhere together, resistant to digestive enzymes & neutralizes acids
what are the salivary glands
parotid
submandibular
sublingual
buccal
how much saliva is secreted daily
800ml to 1.5L
What are the two types of protein secretions in saliva
serous=ptyalin (a=amylase)
mucous=mucin
what is the fx of ptyalin/a-amylase
digests starches with a pH 6-7
what is the fx of mucous/mucin
protection
lubricates
What are the major fx's of saliva
oral hygiene
washes away pathogenic bacteria/food particles
proteolytic enzymes
protein antibodies
what are proteolytic enzymes
they are lysozymes that attack bacteria & digest food particles
What are protein antibodies
destroys oral bacteria
where are the pyloric glands located & what do they do
located in the distal 20% of stomach on surfaces of antrum
their job is secretion of mucous, pepsinogen & gastrin
what are the glands that comprise 80% of stomach & surfaces of body and fundus
oxyntic (gastric) glands
What are the 3 cell types that make up the gastric/oxyntic glands
mucous neck cells
peptic chief cells
parietal cells
what makes up the mucous neck cells
mucous
pepsinogen
what makes up the peptic chief cells
pepsinogen
what makes up the parietal cells
HCl & intrinsic factor
what are the parts of the pancreas
head
uncunate process
body
tail pancreatic duct
what is the arterial blood supply to the pancreas
celiac trunk
common hepatic artery
pancreaticoduodenal a
what are the digestive enzymes of the pancrease
pancreatic acini
pancreatic duct/hepatic duct
Duodenum
What does the pancreatic acini secrete
na
hco3 solution
what does the pancreatic duct/hepatic duct secrete
na
hco3 solution combined with enzymes
What are the digestive enzymes of the duodenum
ampulla of vater
sphincter of oddi
Pancreatic juice secreted abundantly in response to chyme where
upper intestine
how are the characteristics of juices determined in the pancrease
types of food in chyme
T/F Insulin is not secreted by same pancreatic tissue that secretes intestinal pancreatic juices
T
How is insulin secreted into the blood stream
islets of langerhans that occurs in islet patches througout pancreas
what do the pancreatic secretions secrete
proteolytic enzymes that breakdown via hyrolysis
pancreatic secretions contains enzymes for digestion of what
fats
carbs
proteins
Pancreatic secretions contains large quantities of hco3 ions that do what
neutralize acidic chyme
The right & left lobes of the liver are divided by what
GB fossa
IVC porta hepatis
what drains the liver lobes
R/L hepatic ducts
what are the ducts of the liver
common hepatic duct
common cystic duct
common bile duct
pancreatic duct
how is fat digestion and absorption occur in the liver
bile acids that emulsifies lrg fat particles that aids in absorption of digested fat end products
what are some basic fx of the liver
fat digestion/absorption
stores glycogen
wast product excretion
Bile secretion
what are the waste products excreted by the liver
bilirubin
excess cholesterol
how much bile is secreted by the liver each day
600-1000ml/day
what does bile contain
bile salts
bilirubin
cholesterol
lecithin
electrolytes
what secretes bile specifically
hepatocytes
what are the principal metabolic fx cells of liver
hepatocytes
What is the flow of bile
bile-canaliculi-terminal bile ducts-common hepatic duct & common cystic duct-common bile duct-gallbladder-duodenum
what is the 2nd portion of bile secretion
watery solution of Na & hco3 ions
what is the hormone stimulus for the 2nd portion of bile secretion in response to flowing bile in ducts
secretin
what types of cells secrete the 2nd portion of bile secretion
epithelial cells lining ducts
how much of an increase in total quantity of bile is increased by adding bicarbonate to further neutralize pancreatic juices
100%
what is the main fx of the gallbladder
bile storage
how much bile can the gallbladder store
30-60ml which is up to 12hrs of secreted bile
what is continually absorbed in the gallbladder
water
sodium
cl
what does the gallbladder do to the bile
concentrates it
when does the gallbladder empty
when food digestion occurs in upper gi tract & especially when fatty foods enter duodenum typically 30 min after a meal ingested
what is the main actions of bile salts
emulsifies fat
absorption of fatty acids
Explain the process that bile salts on emulsifing fat
it takes a detergent action on fat particles and allows fat globules to be broken down in intestinal tract
Absorption of fatty acids in bile salts action
formation of micelles w/lipids
soluble in chyme due to changes in bile salts
move lipids into mucosa for absorption
where do gallstones come from
they come from too much absorption of water from bile, bile acids from bile, too much cholesterol in bile & inflammation of epithelium
this is a type of gland that is compound mucous glands that is in the proximal duodenum btwn the pylorus & ampulla of vater
brunner's glands
What secretes lrg amts of alkaline mucous
tactile or irritation of mucosa
vagal stimulation
GI hormone secretin
What are the 2 types of epithelium in the SMI
goblet cells that secretes mucous
enterocytes that secretes water & electrolytes & reabsorbs water, electrolytes, digestive end products
where do the crypts of lieberkuhn lie
pits in mucosa btwn villi
What is the alkaline secretions pH in the SMI
7.5-8
Secretions of SMI are rapidly absorbed by
Villi
What happens during the circulation of fluid from crypts to villi
a watery vehicle is created for absorption of substances due to contact of chyme on villi
Secretions of the lrg intestine is associated with what
copious mucous & moderate hco3
mucosa similar to SMI
Explain copious mucous & moderate hco3
rate of secretion via direct stimulaltion of mucous cells along with the pelvic nerves of the PNS
how is the mucosa of the large instestine similar to the SMI
crypts of leiberkuhn but no villi
epi cells contain few enzymes
mainly contains mucous for protection & feces formation
what is the pH of the mucous in the lrg I
8.0
What protects the lrg I wall from bacteria activity of fecal matter
mucous
What provides a barrier to keep acids in fecal matter from attacking intestinal wall
mucous
What is 1.5 L of chyme that passes through ileocecal valve into colon
feces
where is most of the water absorbed in the colon
proximal 1/2 where almost all ions absorbed with minimal loss of small na, cl in feces
