2. Syllabus
Digestion in large intestine; microflora of large intestine. Motor action of
large intestine. Periodic action of digestive system organs.
Absorption
Absorption of water and mineral salts in different areas of digestive tract;
absorption of the products of protein hydrolysis and carbohydrates;
antitoxic functions of liver.
3. Digestion in large intestine, microflora
of large intestine.
Most of the bacteria that live in the body—and there are billions of them—live
inside the large intestine. These bacteria are important in digestion and in
keeping the large intestine healthy. The good bacteria that live in the colon
are called the normal flora. They help prevent bad bacteria from
multiplying and causing problems. Some people supplement their diet with
probiotics or with yogurt. Both are loaded with healthy bacterial cultures that
may promote digestion.
Bacteria also help break down fiber. This is an important part of the diet
that contributes to digestive health by preventing constipation. Normal
bacterial flora also secrete vitamin K and vitamin B that is absorbed. The
gases (CO2, H2, CH4) produced is the result of the hard-working normal flora
in the colon.
4. Motor action of large intestine. Periodic
action of digestive system organs.
5.
6. Absorption
Total quantity of fluid that must be absorbed each day
1.5 l ingested fluid
7 l secreted fluid from GI tract
All absorption (But 1.5 l) takes place in small intestine
The rest 1.5l will go through ileocecal valve into the
colon.
7. Folds of Kerckring –
valvulae conniventes
Folds of Kerckring, villi and
microvilli increase the mucosal
absorptive area by nearly 1000-
fold.
Folds of Kerckring the same
valvulae conniventes increase the
SA about threefold.
Valvulae conniventes (up to 8 mm
protrusions) are well developed in
duodenum and small intestine.
8. Absorptive SA - 250 square meter
Villi increase the SA 10-
fold
There are 1000 microvilli
(1 mcm in length and 0.1
mcm in width) in one
villus
Brushboarder increases
the surface area 20-fold
