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Human Physiology Gas Exchange Notes
This is a sample of our (approximately) 3 page long Human Physiology Gas Exchange notes, which we sell as part of the Human Physiology Notes collection, a Grade 7 package written at The British International School, Ho Chi Minh in 2013 that contains (approximately) 32 pages of notes across 6 different documents.
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Human Physiology Gas Exchange Revision
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HUMAN PHYSIOLOGY Gas Exchange
6.4.1 Distinguish between ventilation, gas exchange and cell respiration.(2)
The flow of air in and out of the lungs
Two stages: inspiration (or inhalation) and expiration (or exhalation).
Lungs are not muscular and cannot ventilate themselves - movement controlled by intercostal muscles and diaphragm.
2. Gas Exchange:
This is the diffusion of gases (oxygen and carbon dioxide) to and form the blood at the alveoli and respiring tissues
Alveoli: Oxygen diffuses into the blood from the alveoli and carbon dioxide diffuses from the blood into the alveoli
Tissues: Oxygen diffuses from blood into the cells and carbon dioxide diffuses from cells to the blood
3. Cell Respiration
Production of ATP at the cellular level
Aerobic respiration (mitochondria) = oxygen and produces carbon dioxide
Anaerobic respiration = no oxygen and still produces carbon dioxide
6.4.2 Explain the need for a ventilation system (3)
Large organisms - oxygen and waste products cannot diffuse into and out of cells to and from the directly
Ventilation system ensures blood can be medium to deliver nutrients and remove waste
To maintain a large concentration gradient between alveoli and blood If alveoli is not ventilated, equilibrium would be reached - gas could not be exchanged
Air flow (breathing out) : CO2 concetration in alveoli kept low so it diffuses out of the blood
Airflow (breathing in) : Keeps O2 concetration in alveoli high
Blood flow : blood with high CO2 concentrartion and low O2
This means oxygen can always diffuse down its concentration gradient from the air to the blood, while at the same time carbon dioxide can diffuse down its concentration gradient from the blood to the air.
Humans = Land born
Gases need moist surfaced (membraines) in order to diffuse
Lungs = moist membrane allowing O2 and CO2 to diffuse in and out of blood
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