Digestive System Flashcards
(14 cards)
What does digestion do?
It turns food into a form that your body can use. It is usually insoluble and digestion breaks it down into molecules of smaller soluble substances with the help of enzymes
How many stages does the digestive system have?
Eight
What is stage 1?
Ingestion.
Food goes into the mouth.
Teeth grind food and mix it with saliva.
Saliva is a digestive juice and contains enzymes
What is stage 2?
Salivary glands produce saliva to make food moist and easy to. swallow.
Saliva breaks down starch knot sugar.
What is stage 3?
Food is pushed down food pipe or gullet into stomach.
When you swallow the wind pipe shuts off and food goes into gullet. The muscles contract to narrow tube ABOVE food and push it down to stomach.
What is stage 4?
The stomach churns up food with strong acid and more digestive juices.
Proteins are broken down into amino acids.
What is stage 5
Most digestion occurs in small intestine.more digestive juices are added.
Carbohydrates are digested into sugars.
Sugar and amino acids are small so their molecules are absorbed into the blood stream through wall of small intestine
What is stage 6
Large intestine takes water out of food that cannot be digested and leaves faeces
What is stage 7
Faeces are stored in the rectum
About 60% of faeces are dead bacteria
What is stage 8
Anus - faeces are egested from here. The process is called egestion or elimination.
What are the 3 main enzymes?
Protease - breaks protein into amino acid molecules
Carbohydrase - breaks carbohydrates into small sugar molecules
Lipase- breaks fat into glycerol and fatty acids
The small useful nutrients then pass through small intestine wall into the blood stream
What are villi?
Thin like fingers in wall of small intestine and create large surface area.
They contain blood vessels and capillaries that carry digested food into veins and into the liver.
How does digested food travel around the body and why
It is carried in the blood.
Blood travels through blood vessels.
Arteries carry blood from heart.
Veins carry blood to the heart.
Smallest blood vessels are capillaries.
Substances enter and leave blood through capillaries.
Cells get the substances they need from blood in the capillaries.
What do cells need food substances for?
To release energy
To make new substances.
Cells use a chemical reaction called respiration to release energy from a sugar called glucose.
