Introduction and Physiological Introduction and Physiological anatomy of Gastro Intestinal tractanatomy of Gastro Intestinal tract

Every cell of living system needs energyUnicellular organisms: Exists in the sea of nutrients Can satisfy their nutritional need just byProteins present at the cell membrane

Multi cellular organismsMulti 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

The FoodThe FoodThe 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

Digestive systemDigestive system

Components of GITComponents 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

Structure of wall of the GITStructure of wall of the GIT

Structure of wall of the GITStructure of wall of the GIT

Structure of intestinal villiStructure of intestinal villi

Salivary functions and its Salivary functions and its regulationregulation

Saliva is the mixed glandular secretion which constantly bathes the teeth and the oral mucosa

First secretion encounter the foodIt is vital for oral healthIt is constituted by the secretions of

the three paired major salivary glands; Parotid, sub mandibular and

sublingualIt also contains the secretions of the

minor salivary glands

Structure of salivary GlandsStructure of salivary Glands

Parotid glandParotid 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

Structure of sub mandibular and sub Structure of sub mandibular and sub lingual glandlingual gland

Submandibular and sub lingual Submandibular and sub lingual glandgland

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.

Structure of salivary glandStructure of salivary gland

Composition of salivaComposition of salivaWater 99.55% solid 0.45%pH 7.04Na, K, Ca, Mg, Cl, HCO3- and

phosphateOrganic substances includesIgA, 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

Functions of salivaFunctions of salivaInitiate the digestion of starchProtects oral cavity (IgA and lysozymes)Provide lubrication for food to make

bolusFacilitate the tasteWhen salivary flow is reduced, dryness

of the mouth occurs and information from osmoreceptors are translated to increase the water intake

Helps in speaking, swallowing, chewingBuffer the gastric secretions reflux in to

the oesophagus

Control of salivary secretionControl of salivary secretionBasically controlled by parasympathetic, sympathetic Basically controlled by parasympathetic, sympathetic stimulation causes proteinaceous secretion without stimulation causes proteinaceous secretion without

affecting the volumeaffecting the volume

Xerostomia (salivary flow< 0.2 ml/min)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