Zusammenfassung der Ressource
Gatrointestinal tract and Digestion
- Can be divided in
- Gastrointestinal (GI) tract
- Organs and Function
- Mouth: The cheeks, hard
and soft palates, lips and
tongue form the mouth.
Saliva is found and
secreted by Salivary
glands. Through
masticaction, food is
mixed with saliva and
shaped into a soft flexible
mass called a bolus
- Pharynx:
funnel-shaped tube
that extends from the
internal nares to the
esophagus
posteriorly and to the
larynx anteriorly, and
it has both
respiratory and
digestive functions.
- Esophagus: Collapsible,
muscular tube that
connects the pharynx to
the stomach. Deglutation
or swallowing moves the
bolus from the mouth to
the stomach
- Stomach: Connects the
esophagus to the
duodenum. Chemical
digestion consists mostly
of the conversion of
proteins into peptides by
enzyme pepsin
- Can cause
- Gastritis: Inflammation,
irritation, or erosion of the
lining of the stomach. It can
occur suddenly (acute) or
gradually (chronic). Gastritis
can be caused by irritation due
to excess alcohol use, chronic
vomiting, stress, or the use of
certain medications such as
aspirin or other
anti-inflammatory drugs.
- Caused by : Helicobacter pylori (H.
Pylori). Bacteria that live in the
lining of the stomach; without
treatment, the infection can lead to
ulcers (painful sores), and in some
people, stomach cancer. Pernicious
anemia. A form of anemia (loss of
red blood cells or lack of
hemoglobin) that occurs when the
stomach lacks a substance needed
to absorb and digest vitamin B12.
Bile reflux. A backflow of bile into
the stomach from the bile tract
(that connects the liver to the
gallbladder). Infections caused by
bacteria or viruses.
- Symptoms: Vary among
individuals, and in many people there
are no symptoms. However, the most
common symptoms include: nausea,
abdominal bloating, abdominal pain, a
burning sensation in the stomach
between meals or at night, hiccups,
loss of appetite, vomiting blood, and
black stools.
- Feces: Consist of
water, inorganic salts,
epithelial cells,
bacteria, and
undigested foods. The
elimination of feces
from the rectum is
called defecation.
- Small intestine: Extends
from the pyloric sphincter
to the ilocecal valve. It is
divided into a duodenum,
jejunum, and ileum. Its
glands secrete fluid and
mucus, and the circular
folds, villi, and microvilli of
its wall provide a large
surface area for digestion
and absorption.
- Large intestine: extends from the
ileocecal sphincter to the anus.
The mucosa contains many goblet
cells, and the muscularis consist of
teniae coli and haustra. The last
stages of chemical digestion occur
in the large intestine through
bacterial action. Substances are
further broken down, and some
vitamins are synthesized. The large
intestine absorbs water, ions, and
vitamins.
- Accesory Digestive Organs
- Pancreas: Large elongated and
flattened organ located inferior
and posterior to the stomach. It
has both an endocrine and an
exocrine function. As an
endocrine gland, it secretes the
hormones insulin and glucagon,
which regulate the blood glucose
levels. As an exocrine gland it
secretes digestive enzymes into
the small intestine to complete
the chemical digestion of foods
- Liver: Located to the right of
the stomach, inferior to the
diaphragm and superior to the
small intestine. The liver has
many different functions in the
body, but the main function of
the liver in digestion is the
production of bile and its
secretion into the small
intestine.
- Gallbladder: Small, pear
shaped organ located just
posterior to the liver. It is
used to store and recycle
excess bile from the small
intestine so that it can be
reused for the digestion
of subsequent meals