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1. Introduction and Physiological anatomy of
Gastro Intestinal tract
Every cell of living system needs energy
Unicellular organisms:
Exists in the sea of nutrients
Can satisfy their nutritional need just by
Proteins present at the cell membrane

2. Multi cellular organisms
 In multi cellular organisms, a groups of
cells converted to a tissue , to perform
specific function
 A number of systems are evolved in
vertebrates including humans
 To provide nutrients to all the systems
The Gastro intestinal tract is accounted
for extraction of nutrients from the food

3. The Food
 The most of the food we eat are
macromolecules , it can not cross the
cell membrane easily
 so it must be converted to monomers
 Gastrointestinal tract is to make the
food in absorbable form by help of
chewing and mixing with various
enzymes in mouth to small intestine

4. Digestive system

5. Components of GIT
Various parts Glands includes
Oral Cavity Salivary glands
Oesophagus Gastric glands
Stomach Pancreas
Duodenum Jejunum Liver and biliary system
Ileum Intestinal glands
Jejunum Endocrine glands
Cecum Enteric nervous system
Colon Circular smooth muscles
Rectum and anal canal Longitudinal muscles

6. Structure of wall of the GIT

7. Structure of wall of the GIT

8. Structure of intestinal villi

9. Salivary functions and its regulation
 Saliva is the mixed glandular secretion
which constantly bathes the teeth and the
oral mucosa
 First secretion encounter the food
 It is vital for oral health
 It is constituted by the secretions of the
three paired major salivary glands;
 Parotid, sub mandibular and sublingual
 It also contains the secretions of the minor
salivary glands

10. Structure of salivary Glands

11. Parotid gland
 Parotid Is large accounts for 50% sec.
of saliva (when stimulated)
 Situated in front of ear behind the
ramus of mandible
 Gland drain in to oral cavity opposite
to second molar tooth
 Secretions are basically serous

12. Structure of sub mandibular and sub lingual
gland

13. Submandibular and sub lingual gland
 The submandibular gland is variable in
size being about half the size of the parotid
 lies above the mylohyoid in the floor of the
mouth.
 It opens into the floor of the mouth
underneath the anterior part of the tongue
 The sublingual is the smallest of the
paired major salivary glands,
 It is situated in the floor of the mouth
beneath the sublingual folds of mucous
membrane.

14. Structure of salivary gland

15. Composition of saliva
 Water 99.55% solid 0.45%
 pH 7.04
 Na, K, Ca, Mg, Cl, HCO3- and phosphate
 Organic substances includes
 IgA, Lysozymes, albumin, glucose, lactate,
urea and ammonia etc.
 Normal salivary flow rates are 0.3-0.4
ml/min when unstimulated and 1-1.5
litre/day when stimulated
 Approximately 0.5 – 0.6 litres of saliva is
secreted perday

16. Functions of saliva
 Initiate the digestion of starch
 Protects oral cavity (IgA and lysozymes)
 Provide lubrication for food to make bolus
 Facilitate the taste
 When salivary flow is reduced, dryness of
the mouth occurs and information from
osmoreceptors are translated to increase
the water intake
 Helps in speaking, swallowing, chewing
 Buffer the gastric secretions reflux in to the
oesophagus

18. Control of salivary secretion
Basically controlled by parasympathetic, sympathetic stimulation
causes proteinaceous secretion without affecting the volume

19. Xerostomia (salivary flow< 0.2 ml/min)
 The presence of saliva is vital to the maintenance
of healthy hard (teeth) and soft (mucosa) oral
tissues.
 Severe reduction of salivary output results in a
rapid deterioration in oral health
 Patients suffering from dry mouth can experience
difficulty with eating, swallowing, speech, the
wearing of dentures, trauma to and ulceration of
the oral mucosa, taste alteration, poor oral hygiene,
a burning sensation of the mucosa,
 oral infections including Candida and rapidly
progressing dental caries
 After radio therapy, old age and multidrug therapy