Transcript The Digestive System ppt

NOTES – DIGESTIVE SYSTEM
ANATOMY
Interesting Digestive System Facts
After you eat how long
does it take for the
stomach to empty?
Within 2-6 hours, all food is
emptied into the small
intestine.
How many
pounds of food
does the
average person
eat in a year?
1,100
How many feet long are your
intestines?
about 20-30 ft long.
Introduction
 The digestive system is
used for breaking down
food into nutrients
which then pass into the
circulatory system and
are taken to where they
are needed in the body.
Introduction
 There are four stages to
food processing:
1. Ingestion: taking in food
2. Digestion: breaking
down food into nutrients
3. Absorption: taking in
nutrients by cells
4. Egestion: removing any
leftover wastes
Oral Cavity
 Begins when food enters
the mouth. (oral cavity)
 It is physically broken
down by the teeth.
 It is begun to be
chemically broken down
by amylase, an enzyme
in saliva that breaks
down carbohydrates.
This is a muscle that:
 Positions food for
chewing
Tongue
 Mixes food with saliva
Amylase is the enzyme
that begins digestion
 Pushes chewed food
(bolus) down the
pharynx for swallowing
Teeth
Anatomy of a Tooth
Teeth
Incisors
Cuspid (canine)
Bicuspids
Molars
Tooth Decay
ROOT CANAL
Salivary Glands
Parotid - ear, cheek
Submandibular - below jaw
Sublingual - under tongue
Salivary Glands
Produce saliva which contains
 water to moisten
 Amylase to begin digestion
 Ions to neutralize food
Soft Palate
 This blocks the opening to the nasal passages to
prevent food/liquid from entering.
Epiglottis
Flap of skin that closes to prevent food from entering.
Pharynx
 Passageway for both food and air
Esophagus
 Muscular tube that carries the bolus of food from the
pharynx to the stomach using involuntary contractions
called peristalsis.
 The bolus passes down
the esophagus by
peristalsis.
 Peristalsis is a wave of
muscular contractions
that push the bolus
down towards the
stomach.
Cardiac Sphincter
 Regulates the entry of
the bolus into the
stomach and prevents
anything from going
back with it is closed.
STOMACH
The Human Digestive System
 To enter the stomach,
the bolus must pass
through the lower
esophageal sphincter, a
tight muscle that keeps
stomach acid out of the
esophagus.
The Human Digestive System
 The stomach has folds
called rugae and is a big
muscular pouch which
churns the bolus
(Physical Digestion) and
mixes it with gastric
juice, a mixture of
stomach acid, mucus
and enzymes.
The Human Digestive System
 The acid kills off any
invading bacteria or
viruses.
 The enzymes help break
down proteins and
lipids. Chemical
Digestion.
 The mucus protects the
lining of the stomach
from being eaten away
by the acid.
The Human Digestive System
 The stomach does do
some absorption too.
 Some medicines (i.e.
aspirin), water and
alcohol are all absorbed
through the stomach.
 The digested bolus is
now called chyme and it
leaves the stomach by
passing through the
pyloric sphincter.
Stomach Lining
Gastric Juices contain acids that break down
food - secreted by gastric glands
PEPSIN - most important digestive enzyme for
breaking down food
Mucus prevents stomach
from digesting itself
Chyme - paste, after food has been broken
down, released then into the duodenum via the
pyloric sphincter valve
Rugae - folds within
stomach
Gastric Pits contain
glands to make
juices
Pyloric Spincter
 Regulates the release of chyme (stomach contents)
from the stomach into the first part of the small
intestine called the duodenum. Once again…no return
trip.
Small Intestine
Starts at the pyloric
sphincter
1. Duodenum
2. Jejunum
3. Ileum
Duodenum
 Where most chemical digestion takes place.
 This is where many chemical come together to break
everything apart for reuse.
Duodenum
Bile, produced in the liver
but stored in the gall
bladder, enters through
the bile duct. It breaks
down fats.
 The pancreas secretes
pancreatic juice to
reduce the acidity of
the chyme.
13. Liver
 Produces bile to
physically break down
lipids into smaller
droplets. Bile is stored
in the gall bladder until
needed.
Liver
1 large right lobe | 1 smaller left lobe
Liver - ducts and vessels
Hepatic duct --> to common bile duct
Hepatic portal vein - circulates blood through liver
Liver Functions
1.
2.
3.
4.
5.
6.
7.
blood glucose levels
breakdown of lipids and fats
protein metabolism
stores vitamins
destroys damaged RBCs
removes toxins
secretes bile
Remember Bili Lights?
Using bili lights is a therapeutic procedure performed on newborn or
premature infants to reduce elevated levels of bilirubin. If blood
levels of bilirubin become too high, the bilirubin begins to dissolve
in the body tissues, producing the characteristic yellow eyes and
14. Gall Bladder stores bile
15. Bile Duct
 A tube that helps transport the bile from the gall badder to the
duodenum.
16. PANCREAS –
secretes insulin which breaks down sugars
Produces insulin and glucagon
Pancreatic Juice also breaks down fat
createsIons to maintain pH – neutralize acids
17. Jejunum


The jejunum is where
the majority of
absorption takes place.
It has tiny fingerlike
projections called villi
lining it, which
increase the surface
area for absorbing
nutrients.
Villi contain microvilli

Each villi itself has tiny fingerlike projections called
microvilli, which further increase the surface area for
absorption.
4/4/2017
47
Ileum

The last portion of the small
intestine is the ileum, which
has fewer villi and basically
compacts the leftovers to
pass through the cecum into
the large intestine.
Increased surface area
increases the absorption
rate.
Appendix
 What is it for anyway
and why is it so
dangerous?
The Human Digestive System
 The large intestine (or
colon) is used to absorb
water from the waste
material leftover and to
produce vitamin K and
some B vitamins using
the helpful bacteria that
live here.
The Human Digestive System
 All leftover waste is
compacted and stored at
the end of the large
intestine called the
rectum.
 When full, the anal
sphincter loosens and
the waste, called feces,
passes out of the body
through the anus.
Digestion and Homeostasis
 The endocrine, nervous,
digestive and circulatory
systems all work together
to control digestion.
 Before we eat, smelling
food releases saliva in
our mouths and gastrin
in our stomachs which
prepares the body for a
snack.
The Hormone Gastrin
Digestion and Homeostasis
 A large meal activates
receptors that churn the
stomach and empty it
faster.
 If the meal was high in
fat, digestion is slowed,
allowing time for the fat
to be broken down.
 Hence why we feel fuller
after eating a high fat
meal.
 Acid Reflux
 Symptoms- burning sensation
 RX- avoid chocolate and
peppermint, coffee, citrus, fried
or fatty foods, tomato products –
stop smoking- take antacids –
don’t lay down 2-3 hours after
eating.
 When small quantities of
stomach acid are regurgitated
into the esophagus
Inflammation of mucous membrane lining of stomach
and intestine
Common cause = Virus
Symps – diarrhea and vomiting for 24-36 hours
Complication = dehydration
 Sore or lesion that forms in
the mucosal lining of the
stomach
 Cause – H. pylori (bacteria) is
primary cause
 Lifestyle factors that
contribute: cigarette smoking,
alcohol, stress, certain drugs.
 Diagnosis – x-ray, presence of
bacteria
 A sac attached to the




cecum and has no
known function.
When appendix becomes
inflamed
If it ruptures, bacteria
from appendix can
spread to peritoneal
cavity.
Symptoms- RLQ pain,
rebound tenderness,
fever, nausea, and
vomiting
RX - appendectomy
 Infectious hepatitis
 Cause – virus
 Spread through
contaminated food or
H2O
 Serum Hepatitis
 Caused by virus found
in blood
 Transmitted by blood
transfusion or being
stuck with contaminated
needles (drug addicts)
 Health care workers at
risk and should be
vaccinated
 Chronic progressive
disease of the liver
 Normal tissue
replaced by fibrous
connective tissue
 75% caused by
excessive alcohol
consumption
Gallstones
 These “stones” are
made of cholesterol
crystals that can form
in the gall bladder
Cholecystitis:
Inflammation of
gallbladder.
 Gallstones
 Can block the bile duct
causing pain in the
shoulder blades
 Small ones may pass on
their own, large ones
surgically removed
 Surgical removal of
gallbladder =
Cholecystectomy
Diarrhea
Constipation
Jaundice
Loose, watery, frequent
bowel movements when
feces pass along colon to
rapidly
Caused by infection ,
poor diet, nervousness,
toxic substances or
irritants in food
When defecation
delayed, feces becomes
dry and hard
RX –diet with cereals,
fruits, vegetables,
(roughage) drinking
plenty of fluids,
exercise, and avoiding
tension
Yellow color of
the skin
Test Your Gray Matter
Kenny is
jaundiced. What
could have caused
this?
The medical term
that means
inflammation of
the mucous
membrane lining of
the stomach and
intestines is:
When small
quantities of
stomach acid are
regurgitated into
the esophagus, the
resulting condition
is called:
Eating proper
foods such as
cereals, fruits,
vegetables, and
drinking plenty of
fluids can help
avoid what
condition?
The medical term
that means surgical
removal of the
gallbladder is:
What disorder
would cause pain
in the back
between the
shoulder blades?
It is recommended
that all healthcare
workers be
vaccinated for what
disease?
Hepatitis is caused
by?
A condition in
which a sore or
lesion forms in the
mucosal lining of
the stomachs
called?