• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Breathing and the lungs.

Extracts from this document...


The lungs are like big air sacs. They are situated in the thoracic cavity. The lungs are very large and spongy. They have a big inside surface area. They're moist and they have a good blood supply. The lungs are protected by the rib cage and situated above the diaphragm muscle. I know from studying GCSE Biology that we breathe in air through our nose and mouth. It is much safer for us to breathe through our nose rather than our mouth. This is because of the tiny hairs that are present in our nose. This causes the air coming in to be cleaned, heated and moistened therefor the air is much cleaner going into our lungs. Once the air has entered through our nose or mouth it travels down our wind- pipe which is also known as the trachea. ...read more.


When we breathe IN the intercostal muscles CONTRACT. These muscles move the ribcage UPWARDS increasing the volume o f Oxygen present in the lungs. The diaphragm moves DOWNWARDS, which makes it flatten out this therefore making the chest larger. My tutor gave me these diagrams from the "Biology for you" teachers handbook. When we breathe OUT the intercostal muscles RELAX. The ribcage LOWERS and the chest decreases in volume. The diaphragm relaxes and moves UPWARDS back into its original position. The exhaled air is then forced out of our lungs and into the outside world. A simple and quick way to show how the lungs operate is to use the Bell jar model. The bell jar itself represents the ribcage, which protects the lungs. ...read more.


Is this model a perfect model of the lungs? Although this is the most suitable model of the lungs that I could find there are reasons why this is not a good representation. * Firstly the bell jar that represents the rib cage does not move. I know that when I breathe the ribcage moves up and down and in and out but the model does not show this. * The rubber sheet would not lie flat across, it should lie in a concave shape just like the actual diaphragm does. * There would not be as much space in the lungs as there is in the jar. I know that when I breathe in the lungs take up the whole space of the ribcage but the balloons do not demonstrate this. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Humans as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Humans as Organisms essays

  1. Human biology short notes

    * Lens becomes thinner Control of Light Intensity Bright Light Dim Light Radial muscles (in iris) relax Radial muscles (in iris) contract Circular muscles (in iris) contract Circular muscles (in iris) relax Iris becomes larger Iris becomes smaller Pupil becomes smaller Pupil becomes larger Allows less light to enter the

  2. The effect of exercise on gas exchange and breathing

    Bicarbonate acts as an important extracellular buffer in the body. The second step is to remove the hydrogen ions from the red blood cell cytoplasm. Haemoglobin acts as a buffer and binds to the hydrogen ions, removing them from the cytoplasm.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work