Breathing
A lung model can be used to demonstrate the process of breathing.
The balloons represent the lungs, the glass jar represents the The ribs and upper backbone, and the organs found in the chest. and a rubber sheet represents the A large sheet of muscle that separates the lungs from the abdominal cavity..
The lung model shows inhalation:
- When the diaphragm (rubber sheet) moves down, the volume inside the glass jar (thorax) increases.
- This increase in volume causes a decrease in pressure.
- The lungs (balloons) To fill with air. as air enters until the pressures inside and outside are equal.
The lung model shows exhalation:
- When the diaphragm (rubber sheet) moves up, the volume inside the glass jar (thorax) decreases.
- This decrease in volume causes an increase in pressure.
- The lungs (balloons) To let air out. as air exits until the pressures inside and outside are equal.
There are a few differences between the lung model and the actual process of breathing:
Image caption, Inhalation
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- The ribs and Sets of muscles between the ribs which raise and lower the rib cage. are not represented in the model. When breathing in, the intercostal muscles contract, moving the ribs up and out, increasing the volume of the thorax. When breathing out, the intercostal muscles relax, moving the ribs down and in, decreasing the volume of the thorax.
- In reality, the diaphragm is dome-shaped and flattens during The action of breathing in.. In the model, the rubber sheet is flat and is pulled down to represent inhalation
- The space between the lungs and wall of the thorax is very small but the model shows a large space between the balloons and glass jar.
Effect of exercise on breathing rate and depth
Muscle cells require more energy during exercise. Energy is made during The chemical change that takes place inside living cells, which uses glucose and oxygen to release the energy that organisms need to live. Carbon dioxide is a by-product of respiration..
When exercising, cells will need more oxygen and produce more carbon dioxide as a result of increased respiration.
When blood reaches the lungs, a larger volume of air is needed to replace the oxygen used and remove the carbon dioxide produced by this extra respiration.
In order to supply more oxygen to the exercising cells, the body increases the rate and depth of breathing.
The time taken for the breathing rate to return to normal is known as the recovery time.
This can be used as a measure of fitness.