The respiratory system
- Created by: Nadia
- Created on: 02-01-13 18:29
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- Respiratory System
- most animals need a specialised respiratory system to absorb oxygen from their blood and get rid of waste carbon dioxide from their blood to the air
- respiratory system consists of the nasal cavity, trachea, bronchi, bronchioles, alveoli, lungs, diaphragm, ribs + intercostal muscles
- breathing in happens when the ribs move up + out, the diaphragm moves down
- this increases the volume of the thorax
- when exhaling, these changes are reversed
- respiratory surfaces need to be thin _ moist, have a large surface area +a good blood supply
- gas exchange in mammals take place by diffusion into the alveoli
- inspired air has more oxygen, less carbon dioxide and less water vapour than expired air
- the air we exhale is warmer than the air we inhale
- dust and other unwanted/ foreign particles are prevented from entering the lungs by mucus
- the cilia in the trachea + bronchi pushes the mucus up to be swallowed
- smoking paralyses the cilia, eventually destroying them
- the cilia in the trachea + bronchi pushes the mucus up to be swallowed
- smoking causes lung diseases like lung cancer + enphysema
- cigarette smoke contains carcinogens,tar + nicotine: all are harmful to the body
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