Summary of Digestion

Digestion


Digestive Organs Accessory Organs
Structure Function Structure Function
Mouth  Mechanical Salivary glands  Secretes
(reduces size enzymes that
of food) digest
 Chemical carbohydrates
(saliva digests
carbohydrates)
Oesophagus  Transports Liver  Secretes
food molecules
required for
digestion of
fats
Stomach  Mechanical Gall bladder  Stores
 Chemical secretions
Digestion of Proteins from liver
 Empties into
small intestine
Small Intestine  Chemical Pancreas  Secretes
digestion enzymes and
(proteins, fats, other
carbohydrates) materials into
 Absorption small intestine
(nutrients,
water)
 FINAL
DIGESTION
Large Intestine  Water
absorption
 Faeces
formation

, Digestion




Structure Function
Lumen  Where food enters
 Combines with HCl + digests
Mucosa layer  Food can be taken up here when
passed through membrane and
capillaries
 Villi contribute to increased surface
area to increase digestion. Also causes
food to move slower through tract for
maximum absorption.
Submucosa layer  Contains nerve fibres
Nerve fibres  Co-ordinates digestion, secretion, and
motility
Muscle layer/Muscularis  Contraction
 Inner + outer fibres
 Only in stomach is there another type
of muscle (opaque muscle layer)
Serosa  Acts as buffer
 Protects tract
 Anchors tract to body walls




Digestion Types
 Organic foods mechanically and chemically broken down into smaller units for absorption
1. Intracellular
a. Animals that do not have digestive system
b. Food taken in through phagocytosis
c. Food wastes extruded from cell through exocytosis