Gas exchange and breathing by CGP

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Gas exchange and breathing

You need to get oxygen from the air into your bloodstream. You also need to get rid of carbon dioxide that is in your bloodstream. Funnily enough, this exchange of gases happens in your gas exchange system.

Gas exchange system

The Lungs are like the big pink sponges that are protected by the rib cage

The diaphragm is a muscle that sits underneath the ribcage. It moves up and down when it contracts, this movements helps to get air in and out of your lungs

The air which you breathe in goes through the trachea. This splits into two tubes called the bronchi one going to each lung

The bronchi split into smaller tubes called bronchioles

The bronchioles end at small air sacks in the lungs called alveoli. These are where gas exchange takes place.

Gas exchange happens in the lungs

Air is inhaled into the lungs

Some of the oxygen in the inhaled air passes into the bloodstream to be caused in respiration

Carbon dioxide is a waste product of respiration, in the lungs, it passes out of the blood and is then breathed out

The gasses pass into or out of the bloodstream by diffusion - where a substance moves from where there is a lot of gas to where there is less gas

The lungs are well adapted for gas exchange

They're moist

They have a good blood supply

The alveoli give the lungs a big insu=ide surface area

Inhaling and exhaling is breathing in and out

The chest cavity is like a bell jar. When you breathe in, the diaphragm moves down and up, this increases the volume of the chest cavity which decreases the pressure. So air rushes in to fill the lungs. When the diaphragm moves up and the ribs move down air rushes out.

Lung volume can be measured

Lung volume is the amount of air that you breathe into your lungs in a single breath, lung volume is different for different people. For example, taller people have bigger lung volume than shorter people and some diseases can reduce a persons lung volume. Lung volume can be measured on a spirometer.

Exercise, Asthma and smoking

Exercise

When you exercise, your muscles need more oxygen and glucose so they can respire and release energy to keep you going

During exercise, your breathing rate and depth of breathing increase so that you can get more oxygen into your blood

If you exercise regularly, the muscles will get stronger

This means that your chest cavity can open up more when breathe in so you can get more air into your lungs

Over time, regular exercise can also cause an increase in the number size of the small blood vessels in your lungs and in the number of alveoli. This means that gas exchange becomes more efficient.

Asthma

People with asthma have lungs that are too sensitive to certain things

If asthmatics breath in pet hair, dust, pollen, smoke ect., then the muscles around the bronchioles contract

The lining of the airways becomes inflamed and fluid builds up in the airways making it hard to breathe and this is called an asthma attack

Symptoms of an asthma attack: difficulty breathing, wheezing and a tight chest

When symptoms occur then you will need to use an inhaler containing drugs which will open up the airways

Smoking

Cigarette smoke contains 4 main things: Carbon monoxide, nicotine, tar and particulates

Tar is particularly bad for you because.....

Tar covers up the cilia on the lining of the airways

The damaged cilia can't get rid of mucus properly

The mucus then sticks to the airways making you cough more and this is called smokers cough

The damage builds up and then can eventually lead to bronchitis and emphysema and both these diseases make it difficult to breathe

And tar contains carcinogens which are a substance that can cause cancer

smoking causes cancer in the lungs, throat and mouth