Biology SL chapter 6.4 (Gas exchange)

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Distinguish between ventilation, gas exchange and cell respiration.
Ventilation: exchange of air between lungs and atmosphere, done by breathing. Gas exchange: exchange of oxygen and CO2 in the alveoli and blood stream. happens through diffusion. Cell respiration: release of ATP from organic molecules, enhanced by O2
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Explain the need for a ventilation system
Gas exchange is a passive process and ventilation is needed to maintain concentration gradient in alveoli. O2 is need by cells to make ATP in aerobic respiration. O2 must diffuse from lungs into blood, while CO2 from blood to lungs.
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Features of alveoli that adapt them to gas exchange (TRIM)
Thin wall:1 cell thick so diffusion distance is small.Rich capillary network:alveoli covered in capillaries to maintain concentration gradients.Increased SA:V R:high number of alveoli optimise surf Area.Most:fluid is secreted to stop alveoli collapse
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State the sections of the ventilation system.
Trachea, bronchus, bronchiole, lungs, diaphragm, ribs and intercoastal muscles
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Explain inspiration
1.Diaphragm contracts and flattens downwards. 2. External intercoastal muscles contract, pulling ribs up. 3.This increases volume in thoraic cavity. 4.Air flows in due to reduced pressure in lungs.
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Explain expiration
1.Diaphragm muscles relax and rise. 2. Abdominal muscles contract, pushing diaphragm upwards. 3. External muscles relax, lowering the ribs. 4.This reduces volume in thoraic cavity, pushing out the air.
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Card 2

Front

Explain the need for a ventilation system

Back

Gas exchange is a passive process and ventilation is needed to maintain concentration gradient in alveoli. O2 is need by cells to make ATP in aerobic respiration. O2 must diffuse from lungs into blood, while CO2 from blood to lungs.

Card 3

Front

Features of alveoli that adapt them to gas exchange (TRIM)

Back

Preview of the front of card 3

Card 4

Front

State the sections of the ventilation system.

Back

Preview of the front of card 4

Card 5

Front

Explain inspiration

Back

Preview of the front of card 5
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