Slides in this set
4.1 Why Gas-Exchange?
All aerobic organisms require a constant supply of oxygen to release
energy in the form of ATP during respiration.
The CO2 produced in the process needs to be removed
Build up of CO2 is harmful to the body.
The volume of O2 absorbed and the volume of CO2 removed is large
in mammals. This is because:
1. They are relatively large organisms with a large volume of living cells.
2. They maintain a high body temperature therefore have high
metabolic and respiratory rates.
Mammals have evolves specialised surfaces, called lungs, to ensure
efficient gas-exchange between the air and their blood.…read more
4.1 Mammalian Lungs
The lungs are internal (inside the body). This is because:
The air is not dense enough to support and protect these delicate
They would otherwise lose a great deal of water and dry out.
The lungs are supported and protected by a bony box called the rib
Movement allows ventilation by a tidal stream of air ensuring that
the air within them is constantly replenished.…read more
Supported by rings or cartilage
Prevents collapsing (air pressure falls when breathing)
Tracheal walls muscle lined with ciliated epithelium and goblet
Goblet cells produce mucus trap dirt and bacteria
Cilia moves mucus up the throat then down oesophagus into the
2 divisions of trachea leading to each lungs.
Similar structure to the trachea.
Produce mucus and have cilia.
Larger bronchi are supported by cartilage reduced amount of
cartilage as it gets smaller.…read more