Chapter 3 - Organisation and the digestive system Flashcards
Which forms which? organs, organ systems, tissues
tissues -> organs -> organ systems
What is a tissue?
a group of similar cells that work together to carry out a particular function.
What are 3 examples of tissues and what are their functions?
- Muscular tissue, moves the stomach wall to churn up the food
- Glandular tissue, makes the digestive juices to digest food
- Epithelial tissue, covers the outside and inside of the stomach
What is an organ system?
a group of organs working together to perform a particular function
What is the function of the digestive system?
to break down and absorb food
What 5 organs is the digestive system made up of and what are their functions?
- glands (eg pancreas and salivary), produce digestive juices
- stomach and small intestine, digest food
- liver, produces bile
- small intestine, absorbs soluble food molecules into your blood
- large intestine, absorbs water from undigested food, leaving faeces
What are 2 adaptations of the small intestine?
- covered in villi, help make it possible to absorb the digested food molecules from the gut into the blood
- good blood supply and short diffusion distances to the blood vessels, increases the diffusion and active transport from the small intestine to the blood
Why can’t starch, proteins and fats pass through the walls of the digestive system? solution?
because they are too big so digestive enzymes break them into smaller molecules, like sugars, amino acids, glycerol and fatty acids.
Why do they need to be made smaller?
so they can be absorbed into the bloodstream
What do carbohydrases do? eg of a cabohydrase?
convert carbohydrates into simple sugars like maltose. amylase.
Which 3 places is amylase made in?
the salivary glands, the pancreas and the small intestine
What do proteases do?
convert proteins into amino acids
Which 3 places is protease made?
the stomach (called pepsin when its in the stomach), the pancreas and the small intestine
What are lipids and what do lipases do?
fats and oils. convert lipids into glycerol and fatty acids
Which 2 places are lipases made?
the pancreas, the small intestine
What does bile do? and why?
bile is an alkaline, it neutralises the hydrochloric acid, because it is too acidic for the enzymes in the small intestine to work, and makes conditions alkaline because they work best in alkaline.
Where is bile produces, stored and released?
in the liver, in the gall bladder, the small intestine
What else does bile do and why?
it emulsifies fats, it breaks down the fat into tiny droplets. this gives a much bigger surface area of fat for the enzyme lipase to work on, which makes digestion faster.
Why is speeding up a reaction by increasing the temperature not good?
because it also speeds up the unwanted reactions as well and there’s a limit to the temperature before the cells start getting damaged and the bonds break. this will change the enzyme’s active site and the substance wont fit anymore so the enzyme is DENATURED
What do enzymes do?
act as biological catalysts and reduce the need for high temperatures. we only have enzymes to speed up reactions in the body
What is a catalyst?
a substance which increases the speed of a reaction, without being changed or used up in a reaction.
What are enzymes?
they are all large proteins and all proteins are made up of chains of amino acids. these chains are folded into unique shapes.
What is unique about an enzyme’s active site and what does it do?
it has a unique shape that fits onto the substance involved in a reaction
What is a substrate?
the substance an enzyme reacts on
