Principles of organisation Flashcards
What is the order of organisation in the body?
Cell –> tissue –> organ –> organ system –> organism
What is a cell?
The basic building blocks of all living things.
What is a tissue? (2)
A group of similar cells which work together to carry out a particular function. It can contain more than one type of cell.
What is an organ?
A combination of tissues carrying out a specific function.
What is an organ system?
Group of organs working together to carry out a particular function.
What is epithelial tissue?
Covers some parts of the body, like the inside and outside of your stomach.
What is glandular tissue?
Makes and secretes chemicals like enzymes and hormones, in the stomach it makes digestive juices to digest food.
What is muscular tissue?
Contracts to move whatever it’s attached to, in the stomach it moves the stomach wall to churn the food.
What does the digestive system do?
Breaks down food, large insoluble molecules, into smaller soluble molecules which we absorb into our blood and gives us energy.
What is the PH in the mouth?
7 (neutral)
What does the mouth do? (2)
Salivary glands make saliva which moistens food to help travel down the oesophagus. Saliva contains amylase to digest starch into sugar.
What do the glands do? (3)
Secrete chemicals like enzymes. Produce amylase in the saliva to break starch into sugar. Produce enzymes and stomach acids in the stomach.
What does the stomach do? (4)
Glands in the stomach lining produce hydrochloric acid and protease (pepsin). The hydrochloric acid kills bacteria and gives the right ph (1-2) for the protease enzyme to work. The protease breaks down proteins into amino acids. The muscular walls then churn the food.
What is the PH in the stomach?
1-2 (acidic)
What tissues are the stomach made of?
Epithelial, glandular and muscular.
What does the pancreas do?
Produces amylase, protease and lipase, releases all 3 in pancreatic juices into the small intestine.
What does the liver do?
Produces bile to be stored in the gall bladder.
What does bile do? (3)
Made in the liver, stored in the gall bladder. Added to the small intestine which helps digestion by emulsifying fat into smaller droplets. Neutralises stomach acid to provide correct conditions for the enzymes present in the small intestine.
What does the gallbladder do? (2)
Stores bile between meals. When you eat, it squeezes bile through bile ducts into your small intestine.
What does the small intestine do? (3)
Has all three enzymes, including lipase which digests lipids into fatty acids. Bile is added into it through gall bladder. The small molecules are absorbed into the blood here from the digestive system.
What is the large intestine?
Where excess water is absorbed into the blood from the food, leaving indigestible food to be faeces.
What is the PH in the small intestine?
8-9 (alkaline)
What is the rectum?
Where faeces is stored until it leaves the anus.
IMPORTANT SUMMARY NOTES: (5)
- starch –> amylase –> sugar
- protein –> protease –> amino acids
- lipids –> lipase –> fatty acids and glycerol
- Mouth has amylase, stomach has protease and HCL, small intestine has all 3 enzymes.
- Food does not pass through the pancreas, but it adds enzymes, the gall bladder, but it stores bile, and the liver but it creates bile.
