digestive system Flashcards
what are the functions of the large intestine
absorb water
absorb vitamins
formation of feces
elimination of feces
are there villi in the L int
no! microvilli
what is the first part of the L int
cecum
what shape is the cecum
large, blind (doesn’t go anywhere) pouch
what is contained in the cecum of the L int
the vermiform appendix
where is the vermiform appendix
posteromedial in the cecum of the L int
where does appendix pain present (quadrant)
RLQ
what does the cecum then attach to
the ascending colon
what flexure is between the ascending and transverse colon
hepatic flexure
what flexure is between the transverse and descending colon
splenic flexure
what is the last part of the colon
sigmoid
what is the most posterior part of the L int
rectum
what muscle in the anus can you control
external iliac sphincter
which flexure of the L int is more superior
the splenic flexure
what is 1
hepatic flexure
what is 2
transverse colon
what is 3
ascending colon
what is 4
cecum
what is 5
splenic flexure
what is 6
descending colon
what is 7/8
sigmoid colon
what structure is the iliocecal valve
a sphincter
what are the 3 most anterior parts of the L int
transverse
cecum
end of descending
what was the patient position in this image
prone
(barium settles in anterior parts)
what flexure is this
hepatic
how is this patient positioned
LPO/RAO erect
how is the hepatic flexure best demonstrated
LPO/RAO erect
how is the splenic flexure best demonstrated
RPO/LAO erect
what gives the small int the “stacked coin” look?
the plicae circularis
what two cell types are in the L int
absorptive cells
goblet cells
where is the body of the tongue
the anterior 2/3 that is in the oral cavity
where is the root of the tongue
the posterior 1/3 that’s in the oropharynx
what is the lingual frenulum
the connection under the tongue
what does the tongue attach to (3)
hyoid
mandible
styloid process of the temporal bone
what are each set of tongue muscles, and what are they for
Extrinsic muscles – move tongue side to side, in and out, form
bolus, and force food back for swallowing
Intrinsic muscles – change shape of tongue for speech and
swallowing
what are papillae
what do they do
taste buds
send information to brain
increase friction to make it easier to form a bolus
what do the lingual glands release
lingual lipase
what does LL do
lingual lipase
begins to break down fat
what are the teeth for
occlusion and mastication
where is the tongue during occlusion
in the oral cavity proper
how much saliva is produced per day
1-1.5L per day
what is the composition of saliva
99.5% water
0.5% solutes
what phase of digestion is the taste, smell, thought of food
cephalic phase
is saliva acidic or basic
slightly acidic
(6.35-6.85)
what is the most important compound in saliva
salivary amylase
what does salivary amylase do
starts the breakdown of simpler sugars
what macro does NOT get broken down in the mouth
protein
what are the 3 salivary glands
parotid or Stensen’s
submandibular or wharton’s
sublingual or Rivinus
where is the parotid gland
in the vestibule opposite the 2nd molar
anterior to EAM
where does the wharton’s duct empty
into the oral cavity proper right adjacent to the lingual frenulum
which salivary glands secretes only serous secretions
parotid gland
what glad produces the majority of the saliva
the submandibular gland
match the gland to the duct
what part of the pancreas is retroperitoneal
body and head
the tail is intrperitoneal
where is the head of the pancreas
L2 or L3
adjacent to the descending duodenum
what is the function distribution of the pancreas
exocrine 99%
endocrine 1%w
what is the difference between endocrine and exocrine
Endo - secretes directly into the blood
exo - secretes into a duct
what cells perform the exocrine functions of the pancreas
acinar cells
what do acinar cells do
secrete pancreatic juice into the pancreatic duct
what is the composition of pancreatic juices
water
pancreatic amylase
proteolytic enxymes
pancreatic lipase
nucleases
what are proteolytic enzymes
enzymes that break down proteins
what are the 2 ducts of the pancreas
pancreatic duct (Wirsung)
accessory (Santorini)
what does the pancreatic duct joints with
what does it form
common bile duct
forms the hepatopancreatic duct
what are the endocrine functioning cells of the pancreas
islets of langerhans
what do the islets of Langerhans in the pancreas do
secrete glucagon and insulin into the blood
what is the ampulla of vader
the hepatopancreatic duct ampulla
how do we know this is the jejunum
the ligament of trites
pulls it up and then back down
how would a patient with gallstones blocking the common bile duct present
RUQ pain
jaundice
what is in the pancreatic duct
pancreatic amylase
pancreatic lipase
inactive trypsinogen
other inactive ezymes
how does trypsinogen become trypsin
trypsinogen leaves the pancreatic duct
meets enterokinase (a brush border enzymes) in the small int
activates and becomes trypsin
what activates the majority of protein digestive enzymes
trypsin
how does pepsinogen activate, and what does it become
meets HCL and becomes pepsin
where is the liver
right hypochondriac and epigastric region
which side of the liver is larger
the right
what separates the right and left lobes of the liver
the falciform ligament
the IVC is lateral to which lobe of the liver
caudate
the gallbladder is lateral to which lobe of the liver
quadrate
what is 1
abdominal aorta
what is 2
IVC
what is 3
caudate lobe of the liver
what is 4
stomach
what is 5
left lobe of the liver
what is 6
right lobe of the liver
what is the large grey structure on the bottom right
spleen
what does the liver produce
bile (emulsifies fats)
what is a main function of the liver
detoxify blood of waste or drugs
what are the 3 cell types of the liver
hepatocytes
bile canaliculi
hepatic sinusoids
what is the #1 functional cell of the liver
hepatocytes
what are bile canaliculi
small ducts between hepatocytes that collect bile
what are hepatic sinusoids
small blood vessels in the liver that allow blood to exchange with the liver’s cells
what is the hepatic portal triad
branch of hepatic artery proper
branch of hepatic portal vein
bile duct
what is the proportion of blood supply to the liver
30% from hepatic artery proper
70% from hepatic portal vein
what is the pulley traction device for
to keep pressure on internal bleeds
to rescue projectile vomiting
the right and left hepatic ducts form what
the common hepatic duct
the common hepatic duct and the cystic duct form what
the common bile duct
what is the cystic duct
comes from the gallbladder, joining with the common hepatic duct, to form the common bile duct
the common bile duct and the pancreatic duct joints to form what
hepatopancreatic duct
what performs chemical digestion in the mouth
lingual lipase
salivary lipase
what performs chemical digestion in the stomach
gastric lipase
pepsin
gastrin
where is gastric lipase from
chief cells
what performs chemical digestion in the small bowel
CCK (cholecystokinin)
secretin
GIP (gastric inhibitory peptide)
where does the majority of chemical digestion occur
in the small intestine
what is the GI tract
gastrointestinal tract
one continuous tube from the mouth to the anus
what are the accessory digestive organs (6)
teeth
tongue
salivary glands
liver
gallbladder
pancreas
(top to bottom) what is 1
oral cavity
(top to bottom) what is 2
pharynx
(top to bottom) what is 3
esophagus
(top to bottom) what is 4
stomach
(top to bottom) what is 5
small intestine
(top to bottom) what is 6
Large intestine
what are the 6 steps of the process if the digestive system
- ingestion
- secretion
- mixing and propulsion
- digestion
- absorption
- defecation
what is ingestion
taking foods and liquids into the mouth
what is secretion
the release of water, acids, buffers, and enzymes
what is the average daily secretion volume?
7L/day
what is mixing and propulsion also known as?
segmentation and peristalsis
what is the motility of the GI tract determined by?
mixing and propulsion
what is the purpose of mixing (segmentation)
increasing the contact of food with digestive chemicals
what is propulsion (peristalsis)
the movement of muscles within the GI tract that facilitate the movement of food
what are the 2 types of digestion
mechanical and chemical
what is mechanical digestion
teeth cutting and grinding food
mixing and churning of food (segmentation
segmentation is what kind of digestion
mechaical
what does chemical digestion do
break down large molecules into smaller ones, so they can be absorbed (catabolism)
which molecules must be broken down to be absorbed
carbohydrates, lipids, proteins, and nucleic acids
which molecules do not require chemical digestion to be absorbed
vitamins, water, ions, and cholesterol
what is absorption
the entrance of digested molecules into blood and lymph
what is defecation
the elimination of wastes, undigested material, bacteria, and cells sloughed from the GI lining
what are the 4 layers of the GI tract
- mucosa
- submucosa
- muscularis
- serosa
what are the 3 layers of the mucosa
epithelium
lamina propria
muscularis mucosae
how often is the epithelium of the mucosa sloughed and replaced
every 5 to 7 days
which layer of GI tract has direct contact with its contents
the epithelium of the mucosa
where is MALT found
in the lamina propria of the mucosa
where are the majority of the blood and lymph vessels in the mucosa
lamina propria
what is MALT
mucosa-associated lymphatic tissue
what does the muscularis mucosae do
folds the mucosa of the stomach and small intestine into small folds
what is the purpose of the small folds in the small intestine and stomach
increases surface area and allows for expansion
what does the submucosa of the GI tract contain
the submucosal plexus
what is the submucosal plexus
an extensive network of neurons
describe the muscle fiber orientation in the inner and outer layers of the muscularis
inner - smooth, circular fibres
outer - smooth, longitudinal fibres
where is skeletal muscle found in the GI tract (4)
mouth, pharynx, upper esophagus, external anal sphincter
where is the myenteric plexus found
in the muscularis if the GO tract
what does the serosa form?
the visceral peritoneum
where in the GI tract is the serosa layer NOT present
in the esophagus
what is the peritoneum
the largest serous membrane in the body
what is the parietal peritoneum
lines the walls of the abdominal cavity
what is the visceral peritoneum
lines SOME of the organs and acts as their serosa layer
what is the peritoneal cavity?
what does it contain
the space inside the abdominal cavity
all the organs, peritoneal fluid
what are the 5 peritoneal folds
greater omentum
lesser omentum
falciform ligament
mesentery
mesocolon
what is the largest peritoneal fold
the greater omentum
what does the greater omentum hang from and attach to
the greater curvature of the stomach
the transverse colon
the greater omentum drops anterior to the ___
small intestine
what does the greater omentum contain
may contain a considerable amount of adipose tissue
many lymph nodes for containing and fighting infections
where does the lesser omentum extend from and to
the inferior edge of the liver
lesser curvature of the stomach
what’s does the lesser omentum contain
the portal triad ad lymph nodes
what is the portal triad
proper hepatic artery
hepatic portal vein
common bile duct
what does the falciform ligament attach fro and to
liver
to the anterior abdominal wall, and diaphragm
what is the only digestive organ that is attached to the interior abdominal wall
the liver
what does the falciform ligament do
separate the right and left lobes of the liver
what shape is the mesentery
fan-shaped
what does the mesentery bind
the jejunum and ileum
to the posterior abdominal wall
what does the mesocolon bind
the transverse colon
to the posterior abdominal wall
what do the mesentery and mesocolon do
hold the intestines loosely in place
while allowing movement from muscular contractions
where is the peritoneal cavity
between the visceral and parietal peritoneum
what is ascites
an abnormal accumulation of fluid in the peritoneal cavity
what can cause ascites
cirrhosis of the liver
cancer
heart and kidney failure
what is the acronym for the retroperitoneal structures
SADPUCKER
what are the retroperitoneal structures
suprarenal (adrenal) gland
aorta/IVC
duodenum (2nd/3rd part)
pancreas (except tail)
ureters
colon (ascending and desc)
kidneys
esophagus
rectum
what parts of the duodenum are retroperitoneal
the second and third parts
what part of the pancreas is NOT retroperitoneal
the tail
what parts of the colon are retroperitoneal
ascending and descending
what are the 4 parts of the oral cavity
mouth / oral/buccal cavity
oral vestibule
oral cavity proper
fauces
what is the oral vestibule
the space between the cheeks, lips, gums, and teeth
what is the fauces
the opening between the oral cavity and the oropharynx
what are the 3 parts of the pharynx
nasopharynx
oropharynx
laryngopharynx
what are the 3 phases of deglutition
(swallowing)
1. voluntary phase
2. pharyngeal phase
3. esophageal phase
what is the voluntary phase of swallowing
bolus of food is pushed against the hard palate by the tongue, moving towards the oropharynx
what is the pharyngeal phase of swallowing
as the bolus moves into the oropharynx,
soft palate closes the nasopharynx,
epiglottis covers the laryngeal opening
what is the esophageal phase of swallowing
esophageal muscle contractions push the bolus towards the stomach
soft palate and piglottis return to their resting positions
how long is the esophagus
25 cm long
where is the esophagus in relation to the trachea
posterior!!
where does the esophagus start, pass, and end
junction with the laryngopharynx
through esophageal hiatus at T10
cardiac antrum, meeting the stomach
what is the esophageal hiatus +vertebral level
opening in the diaphragm at T10
where (VL) are the esophageal sphincters
C6 and T11
what is the junction at the lower esophageal sphincter
the gastroesophageal junction
what controls the opening of the stomach
the cardiac sphincter
are there digestive enzymes in the esophagus
no!!
what is the general stomach shape, and what side is it on?
a “J” shape on the left side
what are the 4 parts of the stomach
cardia
fundus
body
pyloric part
where is the cardiac of the stomach
surrounding the opening of the esophagus
which part (fundus/pyloric) of the stomach is more posterior
the fundus
what are the 3 portions of the pyloric part of the stomach
pyloric antrum
pyloric canal
pylorus
what are the 2 major functions of the stomach
chemical and mechanical digestion
how does the stomach mechanically digest
propulsion and retropulsion
what is propulsion in the stomach
peristalsis from the body of the stomach to the pylorus
what is retropulsion in the stomach
food particles are too large to fit through the pylorus, so the food is forced back to the body of the stomach
what is chyme
food mixed with gastric juices
as a reservoir, how much does the stomach hold
1-1.5L
what 2 ways does the stomach chemically digest
secretes gastric juices
secretes gastric into blood
what 4 things does gastric juice secreted by the stomach contain
HCL
pepsin/pepsinogen
intrinsic factor
gastric lipase
what is HCL for
killing bacteria
activates pepsin
what does pepsinogen do
activate into pepsin
begins the digestion of proteins
what does intrinsic factor do
aids in the absorption of vitamin B12
what does gastric lipase do
aids in digestion of fats
what does gastric do (5)
- stimulates parietal cells to release HCL
- stimulates chief cells to release pepsinogen
- contracts lower esophageal sphincter
- increases stomach motility
- relaxes the pyloric sphincter
what is gastric emptying
the passage of chyme through the pyloric sphicter
at what rate does gastric emptying occur
3 mL of chyme at a time
what is anterior to the surface of the stomach
diaphragm, anterior abdominal wall, left and quadrate lobes of liver
what is on the posterolateral surface of the stomach
the spleen
what is posterior to the stomach
left kidney, pancreas
what do surface mucous cells and mucous neck cells secrete
mucus (forming a protective barrier)
what do parietal cells secrete
intrinsic factor
HCL
what do chief cells secrete
pepsinogen
gastric lipase
what do G cells secrete
gastrin
what is the diameter of the small intestine
2.5 cm
where does most of digestion and absorption occur
in the small intestine
how long is the small intestine in a living person
vs a cadaver
3m in living
6.5 m in a cadaver
how big are plicae circularis
(T/F) they are permanent
10mm
true -permanent
how big are villi
0.5-1mm
how big are mmicrovilli
1 micromm
how long in the duodenum
0.25m
how long is the jejenum
1m
how long is the ileum
2m
what are the 3 parts of the small intestine
duodenum
jejenum
ileum
where (vertebral) does the duodenum run
L1-L4
what are the 4 parts of the duodenum
duodenal bulb
descending
horizontal
ascending
what does the submucosa of the duodenum contain
that do what
duodenal glands or Brunner’s glands
secrete alkaline mucus
what type of digestion does the jejenum perform
chemical digestion
what valve is at the terminal end of the ileum
ileocecal valve
what are the 3 histological types in the small intestine
absorptive cells
goblet cells
crypts of Lieberkuhn
what do the absorptive cells in the small intestine do
form the brush border
produce brush border enzymes
what brush border enzymes are produced by the absorptive cells in SI
carbohydrate enzymes
protein- enterokinase
nucleotide
what does enterokinase active
trypsin
what activates trypsin
enterokinase
what do the goblet cells in the SI do
secrete mucus
what do the Crypts of Lieberkuhn do
secrete 1-2L of intestinal juice (water, mucus, slightly alkaline pH7.6)
what are the 2 types of cells in the Crypts of Lieberkuhn
paneth cells
enteroendicrine cells
what do paneth cells do
secrete lysozyme to regulate the mocirbial population
what are the 3 types of enteroendocrine cells
S cells
CCK cells
K cells
what are S cells
secretin
stim sec of pancreatic juice and bile by causing increased liver output
what are CCK cells
cholecystokinin
acts on gallbladder and stims release of pancreatic juices
what are K cells
gastric inhibitory peptide
stims release of insulin (from pancreas) and slows gastric emptying
what are the 3 phases of digestion
cephalic phase
gastric phase
intestinal phase
what is the purpose of the cehalic phase
to prepare the mouth and stomach for what we are going to eat
what are the receptors for the cephalic pahse
thought, taste, smell of food
what happens during the cephalic phase
increase of saliva, gastric juice, and G cells
when does the gastric phase begin
how long does it last
at the arrival of food
3-4 hours
what happens during the gastric phase
stomach stretches and pH increases
Stimson release of gastric juices
increase in peristalsis
what happens during the intestinal phase
controls rate of chyme entering the small intestine
distension of the duodenum
CCK, GIP and secretin involved
