(Digestive
System)
Digestion
Process to converting food molecule into simpler
forms so body can absorb simpler forms of food to generate energy
Gastrointestinal Tract
The gastrointestinal diagram given below
represents the different parts of the tract that include the oral cavity, esophagus,
stomach, intestines and the anus.
Gastrointestinal Tract Anatomy
and Its Functions
- The
gastrointestinal tract in humans begins at the mouth, continuing through the
esophagus, stomach, and the small and large intestines. - The
GI tract is about 9 meters in length. - There
are many supporting organs, such as the liver, which helps by secreting enzymes
that are necessary for the digestion of food. - The human GI
tract can be divided into two halves, namely:
1.
Upper GI tract
2.
Lower GI tract
Upper Gastrointestinal Tract
·
The upper GI
consists of the following organs:
Mouth
includes the teeth, tongue, and buccal mucous membranes containing the ends of
the salivary glands.- Mouth
functions by chewing the food and breaks up food particles. - Salivary
glands produced saliva which maintain moisture and lubricates food. - Salivary
secret Amylase and its cleaves starch
Pharynx
·
The
pharynx is enclosed in the neck and throat.
·
Part
of both the digestive system and the respiratory system.
·
Protects
the food from entering the trachea and lungs.
·
Help
in Swallows foods.
Esophagus
·
A
muscular tube-like structure that functions by carrying food to the stomach.
Stomach
·
Stomach
is a J-shaped bag-like organ that stores the food temporarily, breaks it down,
mixes and churns it with enzymes.
·
Pepsin
Cleaves protein.
·
HCL
Activates enzyme, breaks up food, kill germs.
·
Mucous
protects stomach wall.
·
Limited
absorption.
Liver
·
Liver
is a large, meaty organ that situated on the right side of the belly.
·
Liver
has 2 section called right and left lobes.
·
Liver
function as breaks down and build up many biological molecule.
·
Store
vitamin and iron.
·
Destroys
old blood cells and poisons.
·
Produces
bile which help process and digest fat and remove toxins.
·
Gallbladder – Store bile.
Pancreas
·
Pancreas
is an orgen located in the abdomen.
·
Pancreas
has two main function – Exocrine (digestion), another is Endocrine function.
·
Endocrine
function Regulate blood glucose level.
·
Pancreas
secrets hormones including insulin and glycogen also secrets enzyme such as
Lipase, Amylase, Trypsin and chymotrypsin.
·
Bicarbonates
neutralize stomach acid
·
Trypsin
and chymotrypsin (Proteases) cleaves Protein.
·
Carboxypeptidase
cleaves protein.
·
Amylase
cleaves starch and glycogen.
·
Lipase
cleaves lipids.
·
Nuclease
cleaves nucleic acid.
Lower Gastrointestinal
Tract
The
lower GI consists of the following organs:
Small Intestine
·
The
small intestine is a coiled thin tube, about 6 meters in length.
·
Most
digestion takes place here.
·
Mucous
protect gut wall
·
Absorbed
Nutrients.
·
Protease
cleaves proteins.
·
Sucrases
cleaves sugars
·
Amylase
cleaves starch and glycogen
·
Bile
aids in digestion.
·
Lipase
cleaves lipids.
·
Nuclease
cleaves Nucleic acid.
·
The
surfaces of the small intestine function by absorbing the nutrients from the
food into the bloodstream, which carries them to the rest of the body.
Large Intestine
·
The
large intestine, also known as the Colon,
·
It
is a thick tubular organ wrapped around the small intestine.
·
Its
primary function is to process the waste products.
·
Absorb
any remaining nutrient, ions and water back into the system.
Rectum
- Expels
waste.
Anus
- Opening for
waste elimination.
Steps in digestion
Breakdown of food in mouth by teeth and saliva enzyme mixed on it.
Transfer of partially digested food through esophagus.
Further digestion in stomach by digestive juice.
Complete digestion and absorption in small intestine.
Assimilation of absorbed food.
Absorption of water and waste generated in large intestine.
Waste stored in Rectum and excreted out via anus.
Disease Related to Gastrointestinal systems
Gastrointestinal Tract Infection
·
Gastrointestinal
infection can be caused by viruses, bacteria and parasites that cause
inflammation of the gastrointestinal tract, gastroenteritis.
·
These
might infect both, the stomach and the small intestine.
·
The
microorganisms that can cause these infections include adenovirus,
campylobacter, E.coli, Staphylococcus
aureus, etc.
Constipation
·
Constipation
refers to infrequent or incomplete bowel movement.
·
This
is caused due to inadequate fibers in the diet.
Irritable Bowel Syndrome
·
This
is a condition in which the colon muscle contracts more often than in normal
people.
·
It
causes bloating, abdominal pains and cramps, diarrhoea, etc.
Colon Cancer
·
Colon
cancer begins in the large intestine and affects older people.
·
It
begins as small, non-cancerous clumps.
·
These
clumps gradually convert to cancer.
·
It
can be treated with surgery, chemotherapy, and radiation therapy.
Haemorrhoids
·
These
are swollen blood vessels that line the opening of the anus.
·
They
are caused by excess pressure due to the strenuous movement of the bowel.
Gastrointestinal Tract (Digestive System) Notes PDF
Gastrointestinal Tract (Digestive System) Notes PPT
