GASTROINTESTINAL PHYSIOLOGY
(Human Touch Notes)
Subject: Human Physiology
Topic: Gastrointestinal System
Includes:
• Functions of digestive organs
• Digestive juices – composition, functions & regulation
• GI hormones
• Common GI disorders (pathophysiology)
• Exam-oriented cycles & flow concepts
Prepared By:
Alina Siddiqui
Qualification:
M.Sc. Dietetics & Food Service Management
For Students of:
Nutrition | Dietetics | Nursing | Medical & Health Sciences
Purpose:
Easy understanding • Concept clarity • Exam preparation
, Gastrointestinal Physiology
Introduction
Gastrointestinal (GI) Physiology is the study of the structure and functions
of the digestive system. It explains how food is ingested, digested,
absorbed, and eliminated from the body. The digestive system plays a vital
role in maintaining nutrition, energy balance, growth, and overall health.
The GI tract is a long muscular tube extending from the mouth to the anus,
assisted by accessory organs like the liver, pancreas, and gall bladder.
Functions of Gastrointestinal System
The major functions include:
• Ingestion – intake of food
• Secretion – digestive enzymes, acids, mucus, and bile
• Motility – mixing and movement of food
• Digestion – mechanical and chemical breakdown
• Absorption – nutrients into blood and lymph
• Defecation – elimination of waste
Structure of Gastrointestinal Tract
1. Mouth (Oral Cavity)
• First site of digestion
• Mechanical digestion by chewing
• Saliva contains salivary amylase (ptyalin) which begins carbohydrate
digestion
• Food is converted into a soft mass called bolus
, Figure 1: Diagrammatic representation
2. Pharynx
• Connects mouth to esophagus
• Plays an important role in swallowing (deglutition)
3. Esophagus
• Muscular tube ~25 cm long
• Transports food from pharynx to stomach
• Movement occurs by peristalsis
• No digestion or absorption
4. Stomach
• J-shaped muscular organ
(Human Touch Notes)
Subject: Human Physiology
Topic: Gastrointestinal System
Includes:
• Functions of digestive organs
• Digestive juices – composition, functions & regulation
• GI hormones
• Common GI disorders (pathophysiology)
• Exam-oriented cycles & flow concepts
Prepared By:
Alina Siddiqui
Qualification:
M.Sc. Dietetics & Food Service Management
For Students of:
Nutrition | Dietetics | Nursing | Medical & Health Sciences
Purpose:
Easy understanding • Concept clarity • Exam preparation
, Gastrointestinal Physiology
Introduction
Gastrointestinal (GI) Physiology is the study of the structure and functions
of the digestive system. It explains how food is ingested, digested,
absorbed, and eliminated from the body. The digestive system plays a vital
role in maintaining nutrition, energy balance, growth, and overall health.
The GI tract is a long muscular tube extending from the mouth to the anus,
assisted by accessory organs like the liver, pancreas, and gall bladder.
Functions of Gastrointestinal System
The major functions include:
• Ingestion – intake of food
• Secretion – digestive enzymes, acids, mucus, and bile
• Motility – mixing and movement of food
• Digestion – mechanical and chemical breakdown
• Absorption – nutrients into blood and lymph
• Defecation – elimination of waste
Structure of Gastrointestinal Tract
1. Mouth (Oral Cavity)
• First site of digestion
• Mechanical digestion by chewing
• Saliva contains salivary amylase (ptyalin) which begins carbohydrate
digestion
• Food is converted into a soft mass called bolus
, Figure 1: Diagrammatic representation
2. Pharynx
• Connects mouth to esophagus
• Plays an important role in swallowing (deglutition)
3. Esophagus
• Muscular tube ~25 cm long
• Transports food from pharynx to stomach
• Movement occurs by peristalsis
• No digestion or absorption
4. Stomach
• J-shaped muscular organ
