The respiratory system is everything we use to breath.
You need to be able to understand how we breathe to get oxygen into the body and to get rid of waste carbon dioxide.
The Trachea is split up into two bronchus which leads into both our lungs. The bronchi are further distributed into bronchi and bronchiole. The air travels along these tubes and finally ends up in the air sacs (alveoli). The air sacs are surrounded by a network of capillaries and as the blood flows through these capillaries, the oxygen in the air sacs(alveoli) diffuse into the blood, thus reoxygenating them. In the cells, the oxygen combines with glycogen to release energy for vital activities of our body.
As we breathe in, the diaphragm contracts and depresses so that a lot of air enters and fills up the lungs. The ribs are therefore raised. When we breathe out, the ribs return to their original position and the diaphragm relaxes and arches upwards. The air is forced out of the lungs and returns the same way it came.
The path the air takes back out is very similar, except that this time round, the blood meets the air sacs and carbon dioxide diffuses out. This carbon dioxide finally returns to the atmosphere when we exhale.
How we breathe
Inspiration - Breathe in
When you inhale:
- The intercostal muscles contract, expanding the ribcage.
- The diaphragm contracts, pulling downwards to increase the volume of the chest.
- Pressure inside the chest is lowered and air is sucked into the lungs.
Expiration - Breathe out
When you exhale:
- The intercostal muscles relax, the ribcage drops inwards and downwards
- The diaphragm relaxes, moving back upwards, decreasing the volume of the chest.
- Pressure inside the chest increases and air is forced out.
Gas is exchanged from the air into the blood stream in the alveoli (tiny air sacs). Waste carbon dioxide is transferred from the blood back into the air also.
Respiration is the release of energy from glucose in the muscles.
When the body is at rest this is aerobic respiration. As you exercise you breathe harder and deeper and the heart beats faster to get oxygen to the muscles.
Glucose + oxygen = energy + water + carbon dioxide
When exercising very hard, the heart cannot get enough oxygen to the muscles. Respiration then becomes anaerobic.
Glucose = energy + lactic acidVital capacity is the most air you can breath in or out in one breath.
Short term effects
You need to know the short term effects exercising has on your respiratory system.
As you exercise your body needs more oxygen. To do this your body changes;
- You breath more quickly
- You also breathe more deeply (take in larger volumes of air each breath)
- If you are doing anaerobic activity then lactic acid will begin to build up in your muscles
- When you stop exercising anaerobically your body will continue to breath heavily to get rid of the lactic acid by repaying the 'oxygen debt'.
Oxygen debt - The amount of oxygen consumed during recovery above that which would have ordinarily been consumed in the same time at rest (this results in a shortfall in the oxygen available)
Long term effects
Exercising regularly has long term benefits on your respiratory system.
The muscles around your chest cavity get stronger - so they can make your chest cavity larger
With a larger chest cavity you can breathe in more air in one breath (increase vital capacity)
Your lungs get more efficient at exchanging gas into and out of the blood stream.
The larger your lung capacity, the more oxygen you can get into your lungs and enter your blood stream per breath.
This means you have a better oxygen supply to the body which means you should be able to exercise for longer.
When you're breathing normally you only breathe a small amount of air in and out. When you exercise you breath deeper so can take more air in with each breath.
Vital capacity is the most air you can breathe in or out in one breath.
You can improve your vital capacity by taking part in regular exercise.
Smoking has a really bad effect on your respiratory system;
- Smoking can lead to lots of different lung diseases like cancer, bronchitis and emphysema.
- Cigarette smoke contains tar that clogs up the alveoli and makes it harder for gas exchange to take place. Eventually the alveoli will stop working. Even if the tar is removed and the alveoli repair they will never be as efficient as they were.
- Cigarette smoke also contains nicotine. Nicotine causes the blood vessels in the lungs to tighten which slows the blood flow in the lungs. This makes the gas exchange process less efficient.