stomat/o
...
gastr/o
...
enter/o
...
proct/o
...
an/o
...
rect/o
...
bil.o
...
chol/e
...
cholangi/o
...
cholecyst
...
choledoch/o
...
orth/o
straight or normal, correct
odont/o
tooth
Tidal Volume (TV)
Amount of air inhaled or exhaled with each breath under resting conditions.
Inspiratory Reserve Volume (IRV)
Amount of air that can be forcefully inhaled after a normal tidal
volume inhalation.
Expiratory Reserve Volume (ERV)
Amount of air that can be forcefully exhaled after a normal ital
volume exhalation.
Residual Volume (RV)
Amount of air remaining in the lungs after a forced exhalation.
Total Lung Capacity (TLC)
Maximum amount of air contained in lungs after a maximum inspiratory
effort: TLC = TV + IRV + ERV + RV
Vital Capacity (VC)
Maximum amount of air that can be expired after a maximum inspiratory
effort: VC = TV + IRV + ERV (should be 80% TLC)
Inspiratory Capacity (IC)
Maximum amount of air that can be inspired after a normal expiration:
IC = TV + IRV
Functional Residual Capacity (FRC)
Volume of air remaining in the lungs after a normal tidal volume
expiration: FRC = ERV + RV
The wall of the stomach has how many layers and what kind of muscle
are they?
3 layers and they are smooth muscle.
What is the additional layer in the stomach?
Oblique Muscle Layer
What direction do the fibers run in, in the Oblique Muscle Layer?
At a angle.
The food you swallow is called what?
Bolus
Stomach is important for what kind of digestion? The 3 layers of
smooth muscle are important when it comes to helping this kind of digestion.
Mechanical digestion. Also important for chemical digestion but
mechanical digestion is the first place that gets the food that has
been chewed up.
What does the additional layer, Oblique Muscle Layer, do?
Really break up the bolus of food since it is a pretty good size.
Inside the stomach there is wrinkles. What are those wrinkles called?
Rugae
Rugae does what?
Allows your stomach to be able to expand and fill up with food.
(So when your stomach is empty it is wrinkled up inside but then it
can stretch when you fill it up with food.)
In each layer of the stomach, the fibers in each layer do what?
The fibers run in a different directions. So the fibers will run one
way in one layer and the fibers will run another way in another layer.
With the fibers running in different directions, it helps with
mechanical digestion.
The main part of the stomach is called the?
Body
The last part of the stomach, where it heads into the small intestine
is called the what kind of region?
Pyloric Region
The Pyloric Sphincter is located where?
In the Pyloric Region, at the end of the stomach.
Pyloric Sphincter does what?
Controls the passage of food from stomach into small intestine.
The lining, the Rugae, are arranged in pits called?
Gastric Pits
Gastric Pit is what kind of cell?
Stomach cells.
Gastric Pit have what to do what?
They are lined with cells that squirt out all the things that we are
going to use to help digest the food in your stomach.
Mucous Cells and Goblet Cells produce what?
Mucus
Why is it important to have mucus on the lining of your stomach?
It protects the lining cells from the stomach acid.
Advil, Asprin, Motrin, etc. can cause stomach ulcers. How?
Those medications inhibits the mucus production, so you start to get
ulcers or sores in your stomach. The acid can have access to those
cells because it destroys that mucous layer.
What are Stem Cells in the stomach for?
Your stomach pH is around 1 to 2, and those lining cells are just
epithelial cells. You have to replace the stomach lining because you
shed the lining. When that happens the stem cells serve to replace the
old cells that died when the lining sheds.
When does our stomach shed the lining?
Every 3 to 6 days.
Parietal Cells secrete (makes/produces) what?
HCl (acid) and Intrinsic Factor
What does HCl (acid) do?
It help chemically digest the bolus. Once, the bolus becomes very
liquidy instead of the firm pieces that you had swallowed, it becomes Chyme.
What is Chyme?
The liquified bolus.
HCl (acid) has what kind of effect?
Anti-bacterial effect. So the HCl helps kill any bacteria that you
might have ate.
HCl activates what?
Inactive forms of digestive enzymes.
There is an enzyme release called Pepsinogen. It is not active but
when acid hits it, it turns into Pepsin. Which is an active enzyme
that digests protein.
HCl (acid) converts what?
It converts the Iron form (Fe3+) that we eat into the absorbable form
(Fe2+) (which is the form that we can absorb out of our digestive
tract into our blood.)
So, Fe3+ ---------> Fe2+
Why do we need iron?
We have to have it to produce hemoglobin. That is the iron in the
center of a "Hem" that Oxygen (O2) binds to.
You have to have intrinsic factor to be able to absorb what?
Vitamin B12
You have to have vitamin B12 for what?
To make red blood cells. (RBCs)
(Erythropoeisis)
So the Intrinsic Factor is made by ____________. Squirted into your
stomach and is necessary for you to be able to absorb ____________.
Parietal Cells and Vitamin B12
Chief Cells secrete (make/produce) what?
Pepsinogen and Gastric Lipase.
So, they make the enzymes that help digest proteins and fats.
Pepsinogen gets converted into what and what do we use it for?
Pepsin and we use it to digest protein.
Gastric Lipase is used for what?
Used to digest fat.
Enteroendocrine Cells and also Neuroendocrine make what?
Hormones that get squirted into the blood stream.
Enteroendocrine Cells make what kind of hormones?
Gastrin and Histamine
G cells are enteroendocrine cells that make what?
Gastrin
Gastrin is what?
A hormone that acts back on the stomach and increases everything the
stomach does essentially. So it will increase gastric motility and
secretion of the parietal cells (HCl). So it increases HCl production.
Histamine stimulates (makes/produces) what?
Parietal cells. So it increases acid production.
Ach is a PSNS (rest and digest ) neurotransmitter that does what?
Is going to stimulate the whole activity, everything that goes on in
the stomach. It is going to increase gastric motility and increases secretions.
SNS will do what in the digestive system?
Inhibit everything related to digestion. So it is going to inhibit
contraction in the wall, motility and secretion.
When you are exercising or if you are nervous, you are not digesting
at that point.
PPI's" is actually called what?
Proton Pump Inhibitors
What do PPI's do?
A proton is a hydrogen ion (H+). When the parietal cells are making
HCl, they pump H+ ions into the stomach.
So, they are drugs that are going to inhibit this pump. Therefore it
decreases the stomach acid. So its going to keep the parietal cells
from pumping out acid. (Nexium, Prilosec, Prevacid)
Mechanical Digestion does what?
Mixes the chyme with all the secretions (all the secretions, enzymes,
and acid).
Chemical digestion does what?
Releases the enzymes that digests proteins, fats, and carbs.
Why is disease resistance a stomach function?
It's hard for any bacteria to grow because of the pH is 1 to 2 so
there is so much HCl in the stomach.
Chyme moves from the stomach into the small intestine through what?
Pyloric Sphincter.
How much chyme can be squirted from the pyloric sphincter into the
small intestine at a time?
Only 3 ml at a time.
Why can the small intestine only takes 3 ml at a time?
They chyme coming from the stomach into the small intestine is very
acidic. The small intestine has a normal pH so it doesnt like the
acid. So it only takes small amounts of chyme at a time so it can
neutralize it before it moves on.
Gastric emptying time is what?
Refers to how long it takes for you to completely empty your stomach
after you eat a meal.
How long does the gastric emptying time take?
4 hours
What things control digestion?
Cephalic Phase, Gastric Phase, and Intestinal Phase
Cephalic Phase is what?
Started by sensory inputs. Like seeing good food or smelling good
food can cause it. Its going to start the digestive process. It is
going to make you feel hungry.
Gastric Phase is what?
Triggered once food hits your stomach. Once the bolus (food) hits the
stomach, it triggers the actions of the stomach. So its going to
trigger the mechanical digestion of the muscle, trigger the release of
acid and enzymes.
Intestinal Phase is what?
Your intestine controls your stomach. This phase is also known as the
Enterogastric Reflex. Reflex that connects your stomach and intestines
that are going to influence digestion.
How does the intestinal phase work?
-The first 3 ml of chyme enters the duodenum (which is the first part
of the small intestine).
-The small intestine can only take that small amount so the duodenum
goes and tells the stomach to stop squirting more chyme from 2
hormones called CCK and Secretin.
-CCK and Secretin stimulate the Pancreas, Gall Bladder and Liver and
they then release digestive enzymes and bile into the duodenum to
attak the 3 ml of chyme.
The small intestine produce what 2 hormones?
CCK and Secretin
What do CCK and Secretin do?
They inhibit gastric activity so that no more chyme goes through
until the small intestine is ready for more chyme. They also stimulate
the accessory organs (pancreas, gall bladder and liver).
Emetic Center or Vomiting Center
You have a vomiting center in your brain stem. So anything you put in
your stomach thats going to get eventually absorbed in our blood is
monitored. If we have some sort of toxin or waste in our system. It
will cause you to vomit. It is going to cause those muscles that
normally contract to push food down to actually contract in reverse
and you throw up.
3 parts of the small intestine are?
#NAME?
What goes on in the small intestine?
Chemical digestion and absorption
Most of your nutrients and water are absorbed out of what?
The small intestine
Why does the small intestine have so much surface area?
Because it has these finger-like projections called Villi.
What do the Villi do in the small intestine?
There to help with absorption. Also there for secretion. So you have
cells in the villi that secrete stuff into the small intestine.
What is digestion in the Duodenum caused from?
Liver, Gall Bladder and Pancreatic secretions. They squirt right into
the duodenum.
Duodenum releases what?
Bicarbonate (HCO3-) which is a base, and it is released to neutralize
the acid that is in the chyme that just came from the stomach.
What does the Duodenum secrete (make/produce)?
CCK and Secretin to have regulation of stomach, liver/gall bladder
and pancreas.
In all 3 parts of the small intestine there is what?
Chemical Digestion, Absorption of nutrients and water (8L is of
nutrients and water is absorbed in the small intestine), and Motility
What are the 2 types of motility?
Segmentation and Peristalsis
Segmentation does what?
Doesn't move the chyme along. It just holds it there and digests it.
The muscle is just contracting on the chyme but not moving it for absorption.
Peristalsis does what?
Is movement. When the muscle contracts and its job is to push that
chyme toward the large intestine after absorption is completed.
Ileum does what?
There is a Ileocecal valve leads into the large intestine and it is
going to be opened as chyme gets there. It opens when pressure hits
the valve. So it is due to pressure and stretch.
How Accessory Organs are arranged:
-Liver has 2 lobes
-Tucked under the liver is the gall bladder.
-Pancreas is behind the stomach
-They all 3 squirt into the duodenum
Gallbladder, Liver and Pancreas are what kind of organs?
Exocrine organs so that means that they squirt into a duct.
Liver and its ducts:
There are 2 ducts coming from the liver. They are the Hepatic Ducts.
There is a Right and Left Hepatic Duct cause there are 2 lobes in the liver.
Right and Left Hepatic ducts fuse into what?
Common Hepatic Duct
Gall Bladder squirts into which duct?
Cystic Duct
Cystic Duct and the Common Hepatic Duct form what?
Bile Duct
Bile duct carries bile from liver and gall bladder into the what?
Duodenum
Pancreas has which duct?
Pancreatic Duct
Pancreatic Duct squirts into what?
Duodenum
Where is Bile made?
The liver produces bile.
Gall bladder does what with bile?
Stores it.
Bile contains what?
Bile acids and some waste products and Bilirubin.
Bile Acids digestion what?
Fats.
If your gallbladder is removed what happens?
You still have a source of bile. Your liver will still produce the
bile but you will just be put on more of a fat restricted diet since
you don't have a place to store the bile.
What does the Bilirubin do in the bile?
So we can excrete the bile out of the body. (Break down hemoglobin
you get bilirubin).
Enterohepatic Circulation is what?
Recycles our bile acid. When you don't have a gall bladder your liver
produces the bile, it goes into the small intestine. What is happening
is you are reabsorbing into our blood our bile acids and they go back
to the liver. About 80% of our bile acids are reabsorbed. We only lose
20% in feces everyday.
Pancreas is a exocrine organ that does what?
Makes digestion enzymes to digest our food. Digests proteins, lipids,
carbohydrates and nucleic acids in the duodenum. Also release HCO3- to
neutralize the acid in chyme.
Arterial Blood Supply
Celiac Trunk, Superior and Inferior Mesenteric arteries and their
branches is the blood supply through the digestive tract.
Hepatic Portal System is what?
When you deliver blood to the Digestive Organs from the arteries,
instead of the veins taking it right back to the heart, we stop at the
liver. Anything you put in your mouth goes to the liver. Liver is a
detoxifying organ and is filled with enzymes that detox whatever we
put in our mouth. Once it is detoxified then it can go to the heart
and then go back to the body.
The capillaries in the digestive organs do what?
Where we absorb the nutrients.
The liver capillaries do what?
They are the Sinusoids. They are the capillaries with big spaces in
between the walls.
Liver detoxifies but it also gets first claim to the nutrients in the
blood. Why?
The nutrients that come out of our digestive system, the liver takes
a lot of them. Like glucose is stored in the liver as glycogen. It
pulls the glucose out of your blood to store it in the liver.
Valsalva Maneuver is what?
You're straining in the bathroom cause you are pooping. It's when you
are squeezing all your intestines and allows you to go poop is this.
Ileocecal valve squirts into what?
The large intestine
What are the 4 parts of the large intestine?
-Ascending Colon (goes up)
-Transverse Colon (goes across)
-Descending Colon (goes down)
-Sigmoid Colon (makes a "S" shape)
What does the large intestine do?
-There is about 800 types of bacteria in here. These are good
bacteria and we need it.
-They ferment or decay any food that makes it there that hasn't been
digested. So you get fermentation in here.
-The bacteria also makes vitamins.
Why do you get diaherra if you take antibiotics?
Because when you take them the antibiotics kills some of the good
bacteria in the large intestine so then you get diarrhea.
Fermentation is what?
The process that produces gas.
We have how much gas in our large intestine?
7 to 10 L of gas in here everyday.
How much gas do we expel in a day?
500 ml
When we expel gas what is it called?
Flatus or farting
What kind of vitamins does the bacteria in the large intestine make?
Vitamins B and K and are absorbed out of our large intestine.
All 3 parts of the small intestine absorb how much water?
8 L a day
The large intestine absorbs how much water?
0.8 L a day
Large Intestine absorbs H20 and NaCl. Why?
The purpose is to just to compact that feces into something that can
come out of the rectum.
The large intestine secretes mucus. Why?
To help things move along.
Defecation is triggered by what?
Rectal stretch (stretch receptors). When the poop gets to that, you
have a sphincter down there and when the pressure of that poop hits
the sphincter, you have to go to the bathroom.
What are the 5 stages of the Digestive System?
#NAME?
Ingestion is what?
Putting food in your mouth.
Digestion is what?
Has 2 different types called Mechanical and Chemical.
Mechanical Digestion is what?
Mouth by teeth and chewing
Chemical Digestion is what?
Uses enzymes and acids to break down food.
Absorption is what?
#NAME?
Compaction is what?
Compacting wastes
Defecation is what?
Pooping
General Structure is the Tubular System but what does it involve?
Mouth, Pharynx, Esophagus, Stomach, Small Intestine, Large Intestine
and Rectum and Anus.
All of the General Structures are made up of what?
Smooth muscle
Where are Sphincters at?
At the bottom of the esophagus, small and large intestines and rectum
and anus.
What is another name for the Digestive Tract or Tubular System?
Alimentary Canal
How long is the Tubular System/Alimentary Canal?
30 feet long
The Accessory Organs include what?
Salivary glands, Liver, Gall Bladder and Pancreas
What are the 3 layers of the tube?
-Mucosa
-Submucosa
-Musculan's Externa
What is the Mucosa?
#NAME?
Submucosa is what?
-Also called the "Meissner's Plexus" or Submucosal Plexus
-Blood vessels are present
Musculan's Externa is what?
-Also know as "Auerbach's Plexus" or Myenteric Plexus
-Made up of 2 layers of muscles
-Muscle fibers run opposite of each other (which is good for contraction)
Are 2 layers make up the Musculan's Externa?
Circular and Longitudal and are both smooth muscle.
Plexus is what?
Spider-web of nerves
Enteric Nervous System is what?
-Local Nervous System so it is an involuntary (does it automatically)
nervous system.
-Auerbach's and Meissner's Plexuses together.
-Can act on muscles without receiving instruction from the brain.
Act locally to cause muscle contraction.
-ANS (PSNS & SNS) can influence, but not control it.
-Short reflexes; self regulated
What does the Submucosal Plexus (Meissner's Plexus) and Myenteric
Plexus (Auerbach's Plexus) do?
#NAME?
PSNS does what?
Long reflexes; increase movement, secretions
(Rest and Digest)
SNS does what?
Long reflexes; decrease motility, secretions
Motility has what 2 kinds of contractions?
Peristaltic and Segmental Contractions
Peristaltic Contractions is what?
Contractions in waves behind bolus (food) to move food down the tract.
Segmental Contractions does what?
Contraction around food to break it down which leads to mechanical
digestion. No movement.
Oral Cavity is what?
#NAME?
What enzymes are being digestion in the Oral Cavity?
-Amylase (Carbs), Lingual Lipase (Lipids), <----activated by (HCl)
-Mucus
-Lysozymes and IgA = attack bacteria in ingestion to kill it
-pH = 7 (max amylase without lipase)
Where does the swallowing become involuntary?
Oropharynx
Where is the Lower Esophageal Sphincter (LES) located?
Between the esophagus and the stomach to keep food from going back up.
What are the 3 muscle layers of the Stomach?
#NAME?
Enzymatic Hydrolysis
addition of water molecule to break bonds
Absorption
passage of cells lining the GI tract into the blood
Digestion
food broken down into smaller pieces
Gastrointestinal Tract Organs
mouth, pharynx, esophagus, stomach, small and large intestines
Accessory Digestive Organs
Tongue, saliva glands, pancreas, liver, gall bladder
4 layers:
Mucosa, submucosa, musculares externa, serosa
4 layers of esophagus
mucosa, submucosa, muscularis externa, adventitia
Process of Digestion
Ingestion, Propulsion, Mechanical Breakdown, Segmentation, Digestion,
Absorption, Defecation
Ingestion
taking in food
Propulsion
moving food down the GI tract
Mechanical Breakdown
smaller pieces
Digestion
touches saliva
Absorption
get into the blood stream
Defecation
pooping
Segmentation
mixing food with digestive juices
Mouth
food enters and mechanical and chemical digestion begins
Hard palate
forces food during chewing
Soft palate
helps close nasopharynx during swallowing
Bolus
ball of food
Lingual frenulum
secures tongue to floor
Tonsils
palatine and lingual: palatine becomes more infected
Pharynx consists of
nasopharynx, oropharynx, larygopharynx
Esophagus
allows food to go from mouth into the stomach;
Heart burn
stomach acid regurgitates back into esophagus
Stomach
bolus turns into chyme; storage tank
Gastric gland secretions
HCL and pepsinogen, which break down protein
Mucosal gland secretions
secretes mucous that prevents stomach from being digested
Emesis
vomiting
Pyloric sphincter
control emptying of the stomach
Rugae
folds that are created when stomach is empty
Small Intestine
from pyloric sphincter to ileocecal valve; duodenum, jejunum, ileum
Large intestine
absorbs remaining water
Salivary glands
parotid gland, sublingual gland, submandibular gland
Liver
produces bile that breaks down fat
Gallbladder
stores bile
Gallstones
too much cholesterol or too little bile salts
Pancreas
produces enzymes that breaks down all sorts of food
Pancreas (exocrine)
produces pancreatic juice
Pancreas (endocrine)
produces hormones insulin and glucagon
SEROSA
OUTER TOUGH CONNECTIVE TISSUE MEMBRANE FOR PROTECTION
MUSCULARIS EXTERNA
LONGITUDENAL AND CIRCULAR MUSCLE LAYERS FOR CONTRACTION
SUBMUCOSA
LOOSE CONNECTIVE TISSUE, BLOOD VESSELS & GLANDS FOR SECRETION
MUCOSA
(A)MUSCULARIS MUCOSA (INTERNA)
(B) LAMINA PROPRIA MADE OF LOOSE CONNECTIVE TISSUE
(C) EPITHELIUM LINNING
FUNCTION FOR DIGESTION AND ABSORPTION OF NUTRIENTS.
Layers of the GI Tract
1. Serosa
2. Muscularis Externa
3. Submucosa
4. Mucosa
Myenteric plexus
(
Auerbach )
Neurons net between circular & longitudinal muscle
layers Controls contractions of muscularis externa
Controls peristalsis, segmentation, haustration and mass
movement
Submucosal plexus
(
Meissner )
Scattered neurons in the submucosal layer Controls
contractions of muscularis mucosa (interna) Controls
glandular secretion of mucosa
Enteric Nervous System Reflexes
Integrated entirely within the gut wall to control GI
secretions and contractions.
Prevertebral
Sympathetic Ganglia Reflexes
Transmit signals between GI sections such as
gastrocolic, enterogastric and
colonoileal
Spinal Cord and Brain
Stem Reflexes
Pain reflexes and Defecation reflexes
Peristalsis
The GI basic propulsive movement in which a contractile ring moves
towards the anus with downstream receptive relaxation. {Law of the Gut}
Mixing
Local intermittent constrictive waves of regular contractions for
chopping and mixing the food
Segmentation
Concentric contractions that divide the small intestine into small segments.
Haustration
Concentric contractions that divide the large intestine into small
haustral segments
Mass Movement
Propulsive contractions that move fecal matter along the large intestine.
Abdominal Aorta
Arterial branches from
Celiac trunk
Hepatic Artery Proper to the Liver
Left Gastric Artery to the Stomach
Splenic Artery to the Spleen.
Superior
mesenteric artery
Small intestine
Ascending colon
Transverse colon
Inferior
mesenteric artery
Descending colon
Sigmoid colon
Rectum.
Liver reticuloendothelial and hepatic cells
remove bacteria, detoxify chemicals and absorb nutrients from the
venous blood.
Hepatic veins
drain all venous blood into the inferior vena cava.
Hepatic Portal Vein
goes to liver
drains from:
*Superior mesenteric vein
*Gastric veins
*Inferior mesenteric vein
*Splenic vein
Cheeks and lips
�keep food between teeth for chewing; essential for speech and
suckling in infants
Tongue
sensitive, muscular manipulator of food
�papillae and taste buds on dorsal surface
�lingual glands secrete saliva, tonsils in root
Hard and soft palate
�allow breathing and chewing at same time
�palatoglossal and palatopharyngeal arches
MASTICATION
Breaks food into smaller pieces to be swallowed
Increases surface area exposed to digestive enzymes
Contact of food with sensory receptors triggers the chewing
reflex
Tongue, buccinators and orbicularis oris manipulate
food
Masseter and temporalis
elevate the teeth to crush food
Medial and lateral pterygoids
swing teeth in side-to-side grinding action of molars
Saliva
Hypotonic solution of 99.5% water and solutes
salivary amylase
begins starch digestion
lingual lipase
digests fat, activated by stomach acid
mucus
aids in swallowing by lubrication
lysozyme
enzymes kills bacteria
immunoglobulin A
inhibits bacterial growth
electrolytes
Na+, K+, Cl-, phosphate and bicarbonate
Functions of saliva
moisten
begin starch and fat digestion
cleans teeth
inhibit bacteria
bind food together into a bolus
Vestibule
space between teeth and cheeks
Functions of the Stomach
(1) Storage:
can eat lots of food at one sitting
(2) Mechanical Digestion
Reduce food to liquid acid chyme by mixing waves
Force small amounts of chyme from stomach into the small
intestine
(3) Chemical digestion
Protein digestion begins by pepsin Fat digestion by
activated lingual lipase
(4) Limited absorption
Aspirin, alcohol, electrolytes, water & drugs
Pepsin
protein digestio
secreted as inactive pepsinogen zymogens
HCl converts it to active pepsin
Lingual lipase
activates fat digestion
Mucous neck cells
secrete protective surface mucus
Parietal cells
secrete hydrochloric acid and intrinsic factor
Chief cells
secrete pepsinogen, gastric lipase & chymocin
Entroendocrine cells
secrete gastric hormones
Regenerative cells
produce new cells
HCL FUNCTIONS
Activates pepsin and lingual lipase Breaks connective
tissue & plant cell walls Liquefies food to form
chyme Converts ingested ferric ions (Fe3+) to ferrous ions
(Fe2+) for absorption and use in hemoglobin synthesis
Destroys ingested bacteria and pathogens
Intrinsic factor
�Essential for vitamin B12 absorption by small intestine which is
necessary for RBCs production and maturation
�Deficiency causes Pernicious anemia
Gastric lipase
digests butterfat of milk in infants
Chymosin
curdles milk by coagulating proteins
Gastrin
Secreted by the {G} cells.
Stimulates gastric acid secretion and mucosal growth.
SMALL INTESTINE FUNCTIONS
(1) Mechanical digestion
�Peristalsis propels chyme along intestine
�Segmentation move chyme back and forth to mix it thoroughly
(2) Chemical digestion
�Enzymes from pancreas and small intestine complete digestion of
protein, starch, disaccharide sugars and fat
�Gallbladder empties bile into small intestine to aid in fat digestion
(3) Absorption of
most substances
Cholecystokinin
Secreted by the {I} cells.
Stimulates pancreatic enzymes and bicarbonate secretions.
Stimulates Gallbladder contractions and Gastric emptying.
Secretin
secreted by the {S} cells. Stimulates pepsin and bicarbonates
secretion. Inhibits gastric emptying.
Gastric
Inhibitory Peptide
Secreted by the {K} cells. Stimulates insulin secretion. Inhibits
gastric acid secretion
Motilin
Secreted by the {M} cells.
Stimulates gastric and intestinal motility
Acinar cells
exocrine cells that secrete digestive enzymes into ducts
Duct cells
secrete the bicarbonates solution that buffer the acidic chyme from
stomach and raise its pH from 2-3 to 7-8
Cholecystokinin
released from duodenum in response to arrival of acid and fat
�causes contraction of gallbladder, secretion of the acinar cells
pancreatic enzymes and relaxation of the hepatopancreatic sphincter
{Sphincter of Oddi}
Secretin
released from duodenum in response to the presence of acidic chyme
�stimulates all ductal cells to secrete more bicarbonate
Gastrin
from stomach and duodenum weakly stimulates gallbladder contraction
and pancreatic enzyme secretion
entrokinase
enzyme from duodenum epithelium cells
Trypsinogen activated to trypsin
the trypsin enzyme
Chemotrypsinogen activated to chemotrypsin
Procarboxypeptidase
activated by the trypsin enzyme to carboxypeptidase.
Starch digestion
�Remaining starch is digested in intestine by pancreatic amylase
�Digestion same as in the mouth
Fats digestion
�Triglycerides digested in small intestine by pancreatic lipase
�Digestion of each triglyceride yields a monoglyceride molecule and
two fatty acid molecules
Bile
from the gallbladder is required for lipase to digest fat more
efficiently. flows from gallbladder down the bile duct into
duodenum to mix with and emulsify the fat.
Emulsification
breaking fat drops into very small droplets (Bile)
Hepatocytes
secretes bile
Gallbladder
stores and concentrates bile
common bile duct
Common hepatic duct and cystic duct from GB unite to form
unites with pancreatic duct
FUNCTIONS OF THE LIVER
(1) Carbohydrate, lipid and protein metabolism
(2) Removal of waste products & detoxification
(3) Storage of glycogen, vitamins and iron
(4) Phagocytosis by Kupffer cells
(5) Activation of vitamin D
(6) Bile synthesis and secretion
(7) Plasma proteins synthesis
Peptidases
digest peptides to amino acids
Intestinal
lipase
digest fats to glycerol & fatty acids
Disaccharidases
digest disaccharides to monosaccharides
Sucrase
sucrose --> glucose + fructose
Maltase
Maltose --> Glucose + Glucose
Lactase
Lactose --> Glucose + Galactose
ABSORPTION IN THE SMALL INTESTINE
DNA and RNA
hydrolyzed by nucleases to nucleotides
nucleosidases and phosphatases of brush border split them into
phosphate ions, ribose or deoxyribose sugar and nitrogenous bases then absorbed
ABSORPTION IN THE SMALL INTESTINE
Vitamins
are absorbed unchanged
A, D, E and K with other lipids -- B complex and C by simple
diffusion and B12 if bound to intrinsic factor
ABSORPTION IN THE SMALL INTESTINE
Minerals
are absorbed all along small intestine
�Na+ co-transported with sugars and amino acids
�Cl- exchanged for bicarbonate
�Iron and calcium absorbed as needed
FUNCTIONS OF THE LARGE INTESTINE
(1) Feces formation
(2) Limited digestion of undigested food by bacteria
(3) Formation of vitamin K and some B vitamins by bacteria
(4) Absorption of some water, electrolytes, vitamins and bile salts
THE INTERNAL ANAL SPHINCTER
IS MADE OF SMOOTH MUSCLE FIBERS.
RELAXED BY PARASYMPATHETIC
PELVIC NERVE STIMULATION.
CONSTRICTED BY SYMPATHETIC
HYPOGASTRIC NERVE STIMULATION.
THE EXTERNAL ANAL SPHINCTER
INNERVATED BY THE
PUDENDAL
NERVE. UNDER VOLUNTARY CONSCIOUS
CONTROL. IS MADE OF SKELETAL MUSCLE FIBERS.
An intrinsic reflex
activate mass movement that fill the rectum and stimulate rectal
stretch receptors
A spinal cord reflex
cause contraction of the rectum and relaxation of the internal anal
sphincter via parasympathetic pelvic nerve signals
A
pudendal
nerve reflex
cause conscious voluntary relaxation of the external sphincter & defecation
Esophagitis
Inflammation of esophageal mucosa.
Dysphagia
Difficulty of swallowing caused by any esophageal obstructions or paralysis.
Paralysis of the Swallowing Mechanism
Caused by muscle dystrophy, myasthenia gravis or diseases that damage
the swallowing center.
Achalasia
Failure of relaxation of the lower esophageal sphincter during
swallowing due to myenteric plexus damage. Food accumulation above the
sphincter forms a
megaesophagus.
Gastritis
Inflammation of the gastric mucosa due to gastric barrier damage.
Achlorhydria
Complete failure of hydrochloric acid secretion by the gastric glands.
Pernicious Anemia
Caused by Intrinsic factor deficiency due to chronic gastritis.
Peptic Ulcers
Excoriated areas of GI mucosa caused by the digestive actions of
gastric secretions
Abnormal Digestion
Can be caused by failure of secretion of pancreatic enzymes due to
pancreatitis or pancreatic duct block.
Tropical
Sprue
Malabsorption due to inflammation of the intestinal mucosa by bacteria.
Nontropical
Sprue
Malabsorption caused by the toxic effects of gluten as in celiac
disease and gluten-sensitive enteropathy.
Constipation
Dry hard feces produced by slow movement of feces through the large
intestine due to any obstructive pathology.
Hirschsprung�s
Disease
Lack of ganglion cells in the myenteric plexus causes absence of the
defecation reflexes and fecal accumulation in the sigmoid colon
forming a megacolon.
Infectious Diarrhea
Caused by viral or bacterial enteritis infections in the large intestine
Psychogenic Diarrhea
Caused by excessive stimulation of the parasympathetic nervous system
during periods of high nervous tension.
Ulcerative Colitis
Extensive ulceration of the large intestine mucosa caused by allergic
or immune destruction leading to severe diarrhea
Paralysis of Defecation
Can be caused by destruction of the conus medullaris nucleus in
spinal cord injuries.
Nausea
Subconscious excitation of the vomiting center by irritative impulses
from the GI tract, lower brain or cerebral cortex
Vomiting
Is the means by which the upper GI tract gets rid of its content. Can
be initiated irritative impulses to the
Vomiting
Center or the
Chemoreceptor Trigger Zone.
Ascites
Accumulation of fluid and protein in the abdominal cavity due to
decreased plasma proteins or high portal capillary pressure
Obstructions
Can occur at any part of the GI tract due to cancer, fibrotic
adhesions or paralysis
Flatus
Gases accumulation in the GI tract from swallowed nitrogen in the air
or bacterial action in the large intestine generating hydrogen,
methane, hydrogen sulfide, indole and skatole.
appendicitis
its an acute inflammation of the appendix, usually resulting from an
obstruction and infection,
symptoms: generalized abdominal pain, nausea and vomitting, mild
fever and elevated white blood cell count.
its treated with appendectomy.
cholecystitis
inflammation of the gallbladder.
when the gallstones form from crystallized cholesterol, bile salts,
and bile pigments, the condition is known as cholelithiasis
symptoms: after eating fatty foods, nausea and vomiting, and pain
that starts under the rib cage and radiates to the right shoulder
treatment: low fat diet, lithography, and or a cholecytectomy.
constipation
is when fecal material remains in the colon for too long, causing
excessive reabsorption of water.
the feces is hard, dry and difficult to eliminate
usually corrected by high fiber diet, adequate fluids, and exercise
cirrhosis
is a chronic destruction of liver cells accompained by the formation
of fibrous connective and scar tissue
causes include hepatitis, bile duct disease, chemical toxins, and malnutrition
symptoms: vary... liver enlargment, anemia, indigestion, nausea, and
vomiting, nosebleeds, jaundice, and ascites
treatment: alcohol avoidence, proper nutrition, vitamin supplements,
rest, infection prevention, and appropriate exercise are encouraged
diarrhea
is a conditon characterized by frequent watery stools
causes are infection, stress, diet, and irritated colon, and toxic substances.
treatment is directed toward eliminating the cause, providing
adequate fluid intake, and modifying the diet.
diverticulitis
is an inflammation of the diverticula, pouches that form in the
intestine as the mucosal lining pushes through the surrounding muscle.
symptoms vary depending on the amount of inflammation but may
include abdominal pain, irregular bowel movements, flatus,
constipation or diarreha, abdominal distention, low grade fever,
nausea and vomiting
treatment methods include antibiotics, stool softening medications,
pain medications, and in sever cases, surgery to remove the affected
section of colon
gastroentritis
is an inflammation of the mucous membrane that lines the stomach and
intestinal tract.
symptoms: abdominal cramping, nausea, vomiting, fever, and diarrhea.
treatment: rest and increased fluid intake
hemorrhoids
are painful, dilated or varicose veins of the rectum and or anus
caused by straining to defecate constipation, pressure during
pregnancy, insufficient fluid intake, laxative abuse, and prolonged
sitting or standing.
symptoms include pain, itching, and bleeding
treatment include high fiber diet, increased fluid intake, stool
softeners, sitz baths or warm, moist compresses, and in some cases a hemorrheoidectomy
hepatitis
a viral inflammation of the liver.
symptoms include fever, anorexia, nausea, vomiting, fatigue, dark
colored urine, clay colored stool, enlarged liver, and jaundice.
treatment include rest and a diet high in protein and calories and
low in fat. a liver transplant may be necessary if the liver is
severly damaged.
hernia
rupture occurs when an internal organ pushes through a weakened area
of natrual opening in a body wall.
symptoms include heartburn, stomach distention, chest pain, and
difficult swallowing
treatment includes a bland diet, small frequent meals, staying
upright after eating and surgical repair
pancreatitis
an inflammation of the pancreas
symptoms include severe abdominal pain that radiates to the back
nausea, vomiting, diaphoresis, and jaundice if swelling blocks the
common bile duct,
Yellow:
Green: Greater Omentum
Pink: Duodenum
Yellow: Ascending Colon
Green: Transverse colon
Pink: Small Intestine
Slide 66
Yellow: Jejunum
Green: Ileum
Pink: Cecum
Slide 66
Yellow: Appendix
Green: Ascending colon
Pink: Rectum
Yellow: Ileocecal Valve
Green:
Pink:
Yellow: Descending colon
Green: Fusion Fascia - slide 34
Pink: Sigmoid Colon
Yellow: Transverse Colon
Green: Descending Colon
Pink: Splenic - Left colic flexure
Yellow: Hepatic - Right colic flexure
Green: Transverse Colon
Pink: Ascending Colon
Yellow: Pancreatic Duct
Green: Fusion Fascia
Pink: Pancreas
Yellow: Right Lobe
Green: Falciform Ligament
Pink: Left Lobe
Yellow: Right Lobe
Green: Left Lobe
Pink: Gallbladder
Yellow: Quadrate Lobe
Green: Vena Cava
Pink: Caudate Lobe
* Pink is pointing at the vertical green
Yellow: Right Hepatic Duct
Green: Cystic duct
Pink: Common Hepatic Duct
Green: Ductus Choledechus Bile Duct (Common)
Slide 62
Yellow: Fundus
Green: Body of stomach
Pink: Pylorus
Slide 62
Green: Greater Curvature
Pink: Lesser Curvature
Yellow: Duodenum
Green: Pancreas
Pink: Pylorus
Yellow: Pancreas
Green: Pancreatic Duct
Pink: Pylorus
* Pink is pointing towards Narrow opening
Yellow: Fundus
Green: Body
Pink: Cardia
Yellow: Duodenum
Pink: Pyloric vestibule
Slide 48
Yellow: Pulp Cavity
Green: Enamel
Pink: Dentine
Yellow: Neck
Green: Crown
Pink: Root
Yellow: Apical Foramen
Pink: Root Canal
Yellow: cement
Pink: Branches of aveolar vessels and nerves