"The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder)."
The study of the structure and function of the digestive system and its organs.
Overview of the Digestive System: An introduction to the organs and processes involved in digestion, including the digestive tract, accessory organs, and the physiology of digestion.
Function of the Mouth and Salivary Glands: A review of the oral cavity and the structures involved in mastication, including the teeth, tongue, and salivary glands.
Esophagus and Swallowing: An overview of the anatomy and physiology of the esophagus and the process of swallowing, including peristalsis and the role of the upper esophageal sphincter.
Stomach and Gastric Function: A detailed examination of the anatomy and physiology of the stomach, including the structure of the gastric mucosa and the role of gastric acid, pepsin, and other enzymes.
Small Intestine: An overview of the structure and function of the small intestine, including the duodenum, jejunum, and ileum, as well as the role of digestive enzymes, bile, and other substances.
Large Intestine: A review of the anatomy and physiology of the large intestine, including the cecum, colon, and rectum, as well as the process of fecal formation and elimination.
Pancreas and Liver: A discussion of the role of the pancreas and liver in digestion and metabolism, including the production of bile, regulation of blood sugar, and synthesis of digestive enzymes.
Microbiome of the Digestive System: An exploration of the diverse microbial communities that inhabit the digestive system and their role in digestion, metabolism, and host health.
Disorders of the Digestive System: An overview of common disorders and diseases of the digestive system, including inflammatory bowel disease, ulcers, and liver and pancreatic disorders.
Nutrition and Metabolism: A review of the role of the digestive system in nutrient absorption and metabolism, including the processing of carbohydrates, fats, and proteins and the regulation of energy balance.
Gross Anatomy: This involves the study of the structure and organization of the digestive system's organs and tissues visible to the naked eye, such as the esophagus, stomach, small and large intestines, liver, gallbladder, and pancreas.
Microscopic Anatomy: This deals with the study of the different cellular structures, tissues and organs that make up the digestive system, including the villi, glands, muscles, and epithelial cells lining the digestive tract.
Developmental Anatomy: This focuses on the embryonic and fetal development of the digestive system, including how the primordial gut tube differentiates into different digestive organs.
Comparative Anatomy: This compares the digestive system of different species of animals, including humans.
Pathological Anatomy: This involves the study of the structural and functional changes that occur in the digestive system due to diseases and disorders, such as ulcers, colon cancer, and Crohn's disease.
Neuroanatomy: This involves the study of the nervous system that controls the digestive system's functions and movement, including the enteric nervous system and extrinsic nerves.
Immunology: This focuses on the study of the immune system cells and molecules in the digestive system, including the gut-associated lymphoid tissues and mucosal immunity.
Biochemistry: This includes the study of the chemical reactions and metabolic pathways that occur in the digestive system for the breakdown and absorption of food nutrients, such as carbohydrates, lipids, and proteins.
Pharmacology: This involves the study of the drugs and medicines that affect the digestive system's functions and treat digestive disorders.
Endocrinology: This focuses on the digestive system's hormones and how they control various digestive functions and metabolic processes, including digestion, absorption, and energy balance.
"Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body."
"The process of digestion has three stages: the cephalic phase, the gastric phase, and the intestinal phase."
"The first stage, the cephalic phase of digestion, begins with secretions from gastric glands in response to the sight and smell of food."
"This stage includes the mechanical breakdown of food by chewing, and the chemical breakdown by digestive enzymes, that takes place in the mouth."
"Saliva contains the digestive enzymes amylase and lingual lipase, secreted by the salivary and serous glands on the tongue."
"Chewing, in which the food is mixed with saliva, begins the mechanical process of digestion."
"This produces a bolus which is swallowed down the esophagus to enter the stomach."
"The second stage, the gastric phase, happens in the stomach. Here the food is further broken down by mixing with gastric acid until it passes into the duodenum, the first part of the small intestine."
"The third stage, the intestinal phase, begins in the duodenum. Here the partially digested food is mixed with a number of enzymes produced by the pancreas."
"Digestion is helped by the chewing of food carried out by the muscles of mastication, the tongue, and the teeth."
"Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues along the wall of the stomach and the rest of the gastrointestinal tract. This initially results in the production of chyme which when fully broken down in the small intestine is absorbed as chyle into the lymphatic system."
"Most of the digestion of food takes place in the small intestine."
"Water and some minerals are reabsorbed back into the blood in the colon of the large intestine."
"The waste products of digestion (feces) are defecated from the rectum via the anus."