Extra biology Flashacrds (Required) Flashcards
What does mascular tissue do?
Can contract to bring about movement.
What does glandular tissue do?
Comtains secretory cells that can produce and release substances, such as enzymes and hormones.
What does epithelial tissue do?
Covers the outside of your body as well as your internal organs.
What is a tissue?
A geoup of cells with similar structure and function working together.
What are organs?
Organs are collections of tissues. Each organ contains several tussues, all working together to perform a specific function.
What process is the stomach involved in?
The digestion of food.
What does the stomach contain that allows it to digest food?
Muscular tissue- to churn the food and digestive juices of the stomach together
Glandular tissue- to produce the digestive juices that break down food
Epithelial tissue- covers the inside and the outside of the organ
What are the two important functions of the pancreas?
- It makes hormones to control blood sugar
- It makes some of the enzymes that digest food
What are organ systems?
Groups of organs that all work together to perform specific functions.
Why do we need a digestive system?
The food we eat is made up of large insoluble molecules. Your body cannot absorb and use these molecules. They need to be broken down or digested to form smaller, soluble molecules
How long is the digestive system?
Between 6 and 9m long
Examples of glands in the digestive system and what do they do?
The pancreas and salivary glands make and release digestive juices containing enzymes to break down food.
What two things happen in the small intestine?
Where food is digested
Enzymes break down the large insolube food molecules into smaller, soluble ones. Once there, they get transported in the bloodstream around your body.
How is your small intestine adapted for this?
It is adapted to have a very large surface area as it is covered in villi.
It has a good blood supply
It has short diffusion distances to the blood vessels. This greatly increases diffusion and active transport from the small intestine to the blood.
What happens to the food after the small intestine?
- The muscular walls of the small intestine squeeze the undigested food onwards into your large intestine
- This is where water is absorbed from the undigested food into your blood
- The material left forms the faeces
- These are stored and then pass out of your body theough the rectum and anus
What happens to enzymes at 40 C?
The protein structure of the enzyme is affected by the high temperature. The long amino chains begin to unravel, and as a result, the shape of the active site changes. The substrate will no longer fit in the active site. The enzyme is now denatured and can no longer act as a catalyst, so the rate of reaction deops dramatically. Work best at 37 C
What is the effect of pH on enzyme action?
A change in pH affects the forces holding the folded protein chains inplace. If there is a change, the shape of the molecule and specific shape of the active site is lost, so the enzyme no longer acts as a catalysts.
Pepsin works best in an ….?
Acidic pH
Why does your stomach produce a thick layer of mucus?
It coats the stomach walls and protects them from being digested by the acid and the enzymes.
What happens if someone develops a stomach ulcer?
The protecting mucus is lost and acid production may increase. The lining of the stomach is then attacked by the acid and the protein-digesting enzymes, which can be very painful.
Where is bile stored until needed?
The gall bladder
Through what is bile squirted on to food in the stomach?
Bile duct
Why does bile neutralise stomach acid?
To provide the alkaline conditions necessary for the enzymes in the small intestine to work most effectively.
What can happen when gall stones form?
They can block the gall bladder and bile duct. They can cause terrible pain and stop bile being released onto the food and reduce the efficiency of digestion.
Features of arteries?
Thick walls
Small lumen
Thick layer of muscle and elastic fibres
Features of veins?
Relatively thin walls
Large lumen
Often have valves
Features of capillaries?
Walls a single cell thick
Tiny vessel with narrow lumen
What is meant by double circulatory system?
- One transport system carries blood from your heart to your lungs and back again. This allows gas exchange to take place.
- The other transport system carries blood from your heart to all other organs of your body and back again.
What are the skin defences?
- Cover your body and act as a barrier. This orevents bacteria nd viruses reaching the tissue beneath. If your damage or cut your skin, the platelets act.
- Your skin prodcues antimicrobial secretions to destroy pathogenic bacteria
- Healthy skin is covered with microorganisms that help keep you healthy and act as an extra barrier to the entry of pathogens
What are the defences of the nose?
-Nose full of hairs and prodcue mucus which both trap particles in the air that may contain pathogens. If in a pollited area, the mcicus when you blow your nose is blackened, showing it works.
Defences of the trachea and bronchi?
They secrete mucus that traps pathogens from the air. The lining of the tubes covered in cilia, tiny like hair projections. The cilia beat to waft the mucus up to the back of the throat where it is swallowed.
Defences of the stomach?
Produces acid and this destroys the microorganisms in tye mcucus you swallow, as well as the majority of the pathogens you take in through your mouth in your food and drink.
Describe how some white blood cells produce antibodies?
These are special chemicals that target particular bacteria or viruses and destroy them. You need a unique antibody for each type of pathogen.
When your white blood cells have produced antibodies once against a praticular pathogen, …?
They can be made very quickly if that pathogen gets into the body again, stopping you getting the disease twice.
Why does the mucus look green?
Some white blood cells contain green enzymes. These whute blood cells destroy cold viruses and any bacteria trapped in the mucus of your nose when you have a cold. The dead white blood cells, along with the dead bacteria, and viruses, are remived in the mucus, making it look green.
Magnification formula
Image size divided by actual size
1 micro metre in pico m
1,000,000
1 micrometre to nano metre
1000
Digestive system
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