Title: A-level Biology/Mammalian Physiology and Behavior/Mammalian Nutrition - Wikibooks, open books for an open world
Headings: A-level Biology/Mammalian Physiology and Behavior/Mammalian Nutrition
A-level Biology/Mammalian Physiology and Behavior/Mammalian Nutrition
Contents
Overview
Enzymes in Digestion
Protein Digestion
Gastroinestinal Tract
Mouth/Oesophagus
Stomach
Digestion
Absorption
Liver/Pancreas
Small Intestine
Digestion
Absorption
Colon
Control of Digestion
Endocrine system
Nervous system
Digestion and Dentition in other animals
Herbivores
Carnivores

Content: Small Intestine
The small intestine consists of three regions - the duodenum, jejunum and the ileum. The structure of the ileum has many numerous tiny folds in the walls, known as villi, made from the mucosa layer, and each villus is around 1mm tall. These villi all have their own microvilli which combined have a great surface area available for absorption. The smooth muscle in the musclaris mucosa can make them contract and sway around for great contact with the food in the lumen, and the villus also have a network of blood capillaries for absorption and transport of food. Beneath the villi are glands called the crypts of Lieberkuhn, which contain goblet cells to secrete mucus. Digestion
The enzymes from the duodenum continue to act, and enzymes that act in the ileum do so while attached to the surface of the epithelial cells of the villi. Some enzymes