GAS EXCHANGE IN HUMANS Flashcards
Why do mammals need a large amount of 02 absorbed and C02 removed
1) they are large organisms
2) maintain a high temperature, so have high metabolic and respiratory rates
What organ do mammals have to exchange gas
lungs
Why are the lungs located inside the body
1) air is not dense enough to support and protect them
2) the body would lose a huge amount of water and dry out
What are the lungs supported by
ribcage
How are the ribs moved
intercostal muscles between them
What are the main parts of the human gas exchange system
1) lungs
2) trachea
3) bronchi
4) bronchioles
5) alveoli
What are the lungs
pair of lobed structures made up of highly branched tubes (bronchioles) that end in air sacs called alveoli
What is the trachea
flexible airway
What is the trachea supported by
rings of cartlidge
Why does the trachea need to be supported
stops it collapsing as the air pressure drops when they breathe in
What are the trachea walls made up of
muscle lined with ciliated epithelium and goblet cells
What are the bronchi
2 divisions of the trachea each leading to the lungs
What do the bronchi produce and why
mucus, to trap dirt particles
What feature do bronchi have and why
cilia, to move dirt laden mucus towards the throught
What is the larger part bronchi supported by
cartilage
What are the bronchioles
series of divisions in bronchi
What are bronchiole walls made up of and lined with and why
muscle, lined with epithelial cells, allows them to contrict so they can control the flow of air in and out of alveoli
What are the alveoli
minute air-sacs that have membranes which are gas exchange surfaces
What is the diameter of the alveoli
100um-300um
What are between alveoli
collagen and elastic fibres
What are the alveoli lined with
eputhelium
What do the elastic fibres between alveoli allow them to do
stretch as they fill with air when breathing in, then spring back to expel the C02 rich air when breathing out
What path does air take as it is breathed in
trachea, bronchi, bronchioles, alveoli
How are alveoli adapted for gas exchange
1) thin exchange surface - alveolar epithelium only one cell thick
2) large surface area (lots of alveoli)
