Transcript intestin colon

Types of digestion
Dr. Jagdish Kaur
P.G.G.Govt. College, Sector 11
CHANDIGARH
Intracellular
digestion
Intracellular digestion
Simple type of digestion which occurs inside the food vacuoles in the
cytoplasm of the cell.
 The nutrients get engulfed by cell through the process of endocytosis.
 When cell engulf large sized liquid nutrients then the food vesical is
known as pinosome
When cell engulf solid nutrients then the vacuoles are known as phagosome.
 After engulfing the food vacuoles get fused with the lysosome
Lysosome have hydrolytic enzymes And low ph
Digestion of the nutrients present inside the food vacuoles..
Intercellular digestion
It is a characteristic of higher animals. In this process the digestion of
food takes place inside the lumen of the digestive track.
It is more complex process then the intracellular digestion.
In this process the digestive enzymes are secreted by the digestive glands
present in the alimentary canal.
In this large amount of nutrients get in short period of time effetely as
compare to intercellular digestion.
Intercellular digestion involve 4 zones
Ingressive zone: it involved uptake of food and mastication of food. this zone
includes mouth, buccal cavity, vestibular cavity and mouth parts(teeth and tongue)..
Progressive zone: it involve conduction and early digestion of food. This zone
includes pharynx and oesophagus .
Degressive zone: it involve the area of alimentary canal in which finally digestion
and absorption of food takes place. This zone includes stomach and small intestine.
The length of small intestine in both herbivores and carnivores are different
Egressive zone: This zone act as temporarily storage of faeces and finally expel it
out of the body. This region involve large intestine rectum and anus.
After digestion starch brake down in to small glucose molecules and fructose molecules.
The fructose get absorb by the intestinal villi through the process of facilitated diffusion.
Glucose and galactose molecules absorb by villi through the carrier translocase
present on the plasma membrane of the villi.
In this process Na+ ion and glucose molecule move inside the villi through symport
method , the carrier translocase proteins have two receptors on their surface , In which
Na+ ion move along the conc. Gradient at high speed due to which energy is generated
which helps to move glucose molecule into the cell.
 when the conc. Of Na+ ion inc. inside the cell then it pump out into the blood vessel
present within the villus in the presence of ATP.
Finally the glucose enters into the blood capillary.
Now, some undigested disaccharides like sucrose, maltose and lactose which are not
absorbed by the villi enters into the large intestine .
Bacterial flora present inside the large intestine helps in the digestion of that
carbohydrates in the large intestine,Out of which only small amount is absorbed.
ASORPTION OF AMINO ACIDS
All the tripeptides , dipeptides and amino acids move into the cells of villi
through the help of co-transporter. There as the dipeptides and trypeptides move
inside the cell by the symport movement of peptide with H+ ion.
Where as the amino acids move inside the cell by symport movement with Na+
ion.
When di and trypeptide migrated inside the cell they brake down into small
amino acids and get diffused into blood vessel .
1.fist transport system transport neutral amino acid in the cell of intestine .
2. second transport system transport acidic amino acids .
3. third transport system transport basic amino acids.
4. forth transport system transport di and trypeptides inside the intestinal
villi cells
ASORPTION OF FATS
Bile salts emulsifier the fats due to which its surface area
increases and digestion will takes place easily.
After digestion of fats, fats get converted to fatty acid,
monoglyceride and small fats molecules.
Fatty acid and monoglycerides get easily absorbed by the
intestinal cells.
In case of small fats molecules they get fist absorbed by the
intestinal cells. Inside cells it get converted to chylomicons and
then it get enter into lymph vessels (lacteals).
HORMONAL CONTROL ON DIGESTION
Digestion involve 8 hormones
Gastrin :stimulate stomach gastric glands to secret gastric juices.
Secretin :stimulates the pancreas and liver to secret sodium
bicarbonates.
Pancreozymin :stimulates the pancreas to release pancreatic enzymes.
CCK :stimulates gall bladder to contract and release bile.
Enterogasterone :inhibits the secretion of gastric juices.
Duocrinin: stimulates the brunner glands to release mucus.
Enterokinin: stimulates intestinal glands to release intestinal juices.
Villikinin: stimulates the villi to increases the surface area of adsorption.
MICROBIAL DIGESTION/ SYMBIOTIC
DIGESTION
Man:- Large intestine-Escherichia coli
& Streptococcus faecalis (colon)
↓↓
1.Protein content of chyle
↓
Amino acids
2.Synthesise vitamins B2 & K
3. Conversion of bile pigments into brown pigments
Contd.
Ruminants/Cud chewing mammals
I. Ruminant stomach-Rumen, Reticulum, Omasum ,Abomasum
II. Rumen symbiotic bacteria l cellulose ferment cellulose into short chain fatty
acids
↓
1. Acetic acid, butyric acid, propanoic acid
↓
Neutralised by sodium
bicarbonate of saliva
2.Formation of proteins frominorganic nitrogen carbon and ammonium salts
3.Vitamin B complex
Termites-TRICHONYMPHA-beta glucosidases
↓cellulose-----sugar
Contd.
Lagomorphs ( Rabbit & hare)
Food escapes action of gastric and intestinal enzymes
Bacteria secrete cellulases convertind cellulose into
still nonabsorbable form
Special kind of faeces at night but not dropped
Directly eaten from anus to pass through gut again for
bacterial action
Coprophagy/ refection