IGCSE Biology 9 Views 1 Answers
Identify in diagrams and images the main organs of the digestive system, limited to: (a) alimentary canal: mouth, oesophagus, stomach, small intestine (duodenum and ileum) and large intestine (colon, rectum, anus) (b) associated organs: salivary glands, pancreas, liver and gall bladder
Identify in diagrams and images the main organs of the digestive system, limited to: (a) alimentary canal: mouth, oesophagus, stomach, small intestine (duodenum and ileum) and large intestine (colon, rectum, anus) (b) associated organs: salivary glands, pancreas, liver and gall bladder
Answered step-by-step
The main organs of the digestive system can be categorized into two groups: the alimentary canal and associated organs. Below is a description of each organ along with their functions.
(a) Alimentary Canal
- Mouth
- Function: The entry point for food where mechanical digestion begins through chewing, and chemical digestion starts with saliva from the salivary glands.
- Oesophagus
- Function: A muscular tube that transports food from the mouth to the stomach through peristaltic movements.
- Stomach
- Function: A hollow organ that stores food and mixes it with gastric juices to continue the digestion process, breaking down food into a semi-liquid form called chyme.
- Small Intestine
- Divisions:
- Duodenum: The first section where most chemical digestion occurs, receiving bile from the liver and digestive enzymes from the pancreas.
- Ileum: The final section where nutrient absorption occurs before passing undigested material to the large intestine.
- Divisions:
- Large Intestine
- Divisions:
- Colon: Absorbs water and electrolytes from indigestible food matter.
- Rectum: Stores feces until they are expelled.
- Anus: The opening at the end of the digestive tract through which feces are excreted.
- Divisions:
(b) Associated Organs
- Salivary Glands
- Function: Produce saliva that contains enzymes to begin the digestion of carbohydrates and lubricate food for easier swallowing.
- Pancreas
- Function: Produces digestive enzymes and bicarbonate, which are released into the small intestine to aid in digestion and neutralize stomach acid.
- Liver
- Function: Produces bile, which helps emulsify fats for digestion, and processes nutrients absorbed from the small intestine.
- Gall Bladder
- Function: Stores and concentrates bile produced by the liver until it is needed in the small intestine for fat digestion.
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