Search results
Results from the WOW.Com Content Network
This releases carbohydrates, protein, fat, and various vitamins and minerals for absorption into the body. Overview of vertebrate digestion In most vertebrates , digestion is a multistage process in the digestive system, starting from ingestion of raw materials, most often other organisms.
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.
Digestive enzymes take part in the chemical process of digestion, which follows the mechanical process of digestion. Food consists of macromolecules of proteins, carbohydrates, and fats that need to be broken down chemically by digestive enzymes in the mouth, stomach, pancreas, and duodenum, before being able to be absorbed into the bloodstream ...
The function of the GI tract is to process ingested food by mechanical and chemical means, extract nutrients and excrete waste products. The GI tract is composed of the alimentary canal, that runs from the mouth to the anus, as well as the associated glands, chemicals, hormones, and enzymes that assist in digestion.
In ruminants, because dietary carbohydrates tend to be metabolized by rumen organisms, gluconeogenesis occurs regardless of fasting, low-carbohydrate diets, exercise, etc. [8] In many other animals, the process occurs during periods of fasting, starvation, low-carbohydrate diets, or intense exercise.
Chewing or mastication is the process by which food is crushed and ground by the teeth. It is the first step in the process of digestion, allowing a greater surface area for digestive enzymes to break down the foods. During the mastication process, the food is positioned by the cheek and tongue between the teeth for grinding.
The small intestine begins at the duodenum and is a tubular structure, usually between 6 and 7 m long. [18] Its mucosal area in an adult human is about 30 m 2 (320 sq ft). [ 19 ] The combination of the circular folds , the villi, and the microvilli increases the absorptive area of the mucosa about 600-fold, making a total area of about 250 m 2 ...
The cephalic phase of digestion is the stage in which the stomach responds to the mere sight, smell, taste, or thought of food. About 20% of total acid secretion occurs before food enters the stomach.