Digestion and the Digestive system in Humans Flashcards
(27 cards)
What is ingestion?
Food taken through the mouth
When does digestion take place?
As it passes along the gut
What are large insoluble molecules? What happens to them?
- Proteins, fats and carbohydrates
- Broken down by enzymes into smaller soluble molecules
What happens to smaller soluble molecules?
- Taken into the blood stream by absorption to be used by the body cells
What happens to food that can not be digested?
Forms into faeces which are removed from the body during egestion
What features are in the digestive system?
- Mouth
- Oesophagus
- Stomach
- Gall bladder
- Bile duct
- Pancreas
- Liver
- Small intestine
- Large intestine
- Anus
What is peristalsis?
- Waves of muscular contraction that move food through the digestive system.
- Peristalsis in the muscle in the gut wall pushes food along
Where does digestion begin?
In the mouth
What enzyme is found in saliva and what does it do?
Amylase, it begins the digestion of starch into glucose
What happens to the food after it is chewed and mixed with saliva?
It is swallowed and passes down the oesophagus to the stomach
What enzyme does the stomach secrete and what does it digest?
Protease, it begins digesting protein into amino acids
What is the role of hydrochloric acid in the stomach?
It kills bacteria and provides the optimum pH for protease enzymes
Where does the food go after the stomach?
It enters the small intestine
What organs release secretions into the small intestine?
The liver and the pancreas
What enzymes does the pancreas release into the small intestine?
Lipases, proteases and carbohydrases
What do carbohydrase enzymes do in the small intestine?
They digest starch into glucose
What do protease enzymes do in the small intestine?
They continue protein digestion into amino acids
What do lipase enzymes do in the small intestine?
They digest fats into fatty acids and glycerol
Where does further digestion of nutrients take place?
Along the rest of the small intestine
What happens in the large intestine?
Excess water is removed and faeces are formed
How is undigested material removed from the body?
It is egested through the anus as faeces
What is bile, and how does it travel to the small intestine
Bile is a mixture of chemicals. It is secreted by the liver, stored in the gall bladder, and carried to the small intestine by the bile duct.
What does bile do?
Breaks up large fat droplets into smaller ones, this increases its surface area to prepare for enzyme action
What does bile make?
The food alkaline which is the optimum pH for the intestinal enzymes to work. It also neutralises the stomach acid carried with food coming from the stomach
