Functional Structure and Physiology of Gastrointestinal Tract Part 1

What is the function of mastication in the oral cavity?

What is the pH of saliva in the mouth?

Which pair of salivary glands secretes a watery and enzyme-rich secretion?

What is the main function of saliva in the oral cavity?

Which nerve supplies the parotid gland with secretory fibers?

What is the approximate total daily secretion volume of saliva?

What is the function of lingual lipase?

Where is HCl secreted from?

What is the main function of lysozymes and Immunoglobulins A in the mouth?

What is the optimal pH for salivary α-amylase (ptyalin) to function optimally?

Which cells in the gastric glands secrete pepsinogen?

What is the primary function of pepsinogens I & II?

What is the main function of lysozymes and Immunoglobulins A in the mouth?

What is the function of gastric lipase in the stomach?

What is the function of lingual lipase in the oral cavity?

Functional Structure of the Gastrointestinal Tract (GIT)

The GIT consists of various organs responsible for the digestion and absorption of food.
It has a complex arrangement that facilitates different digestive functions, including mechanical and chemical breakdown.

Physiology of Oropharynx

The oropharynx plays a critical role in swallowing and the passage of food from the mouth to the esophagus.
It acts as a pathway for both food and air.

Function of the Stomach

The stomach is involved in the breakdown of food particles and the mixing of food with digestive juices.
It regulates the passage of partially digested food into the small intestine.

Function of the Intestine

The intestines are primarily responsible for the absorption of nutrients and water from digested food.
They also play a role in the formation of feces.

Function of the Oral Cavity

Mastication: Mechanical breakdown of food through chewing.
- Enhances taste and smell, contributing to satiety.
- Aids in swallowing and digestion.

Salivary Secretion

Saliva production is approximately 1.5 liters per day.
Saliva is hypotonic with a pH of 6.3-6.8; it becomes more alkaline in the mouth due to CO2 loss.
Salivary Glands: Composed of three pairs.
- Parotid Gland: Produces ~20% of saliva; secretes serous (watery, enzyme-rich) saliva.
- Submaxillary Gland: Produces ~75% of saliva; secretes serous saliva.
- Sublingual Gland: Produces ~5% of saliva; secretes mixed (thick, mucin-rich) saliva.

Functions of Saliva

Facilitates speech and swallowing (deglutition).
Aids in the initial stages of digestion by providing enzymes and moisture.

This lecture covers the functional structure of the gastrointestinal tract, the physiology of the oropharynx, as well as the functions of the stomach and intestine. It also discusses the process of mastication (chewing) and its definition.