Topic 4 - Human Gas Exchange Flashcards
where does gas exchange in the lungs happen?
the alveoli
what does the blood passing next to the alveoli contain?
lots of carbon dioxide and very little oxygen
what happens to oxygen in the alveoli?
oxygen diffuses out of the alveoli (high conc) into the blood (low conc)
what happens to carbon dioxide in the alveoli?
carbon dioxide diffuses out of the blood (high conc) into the alveoli (low conc) to be breathed out
what happens when the blood passing next to the alveoli reaches the body cells?
oxygen is diffused from the red blood cells in the blood (high conc) into the body cells (low conc)
carbon dioxide is diffused into the red blood cells in the blood (low conc) from the body cells (high conc) and is carried back to the lungs
how are alveoli specialised for gas exchange?
- alveoli give the lungs an enormous surface area
- a moist lining for gasses to dissolve in
- thin walls to decrease diffusion distance
- good blood supply to maintain a high concentration gradient
- permeable walls so gases can easily diffuse
what does smoking do to the alveoli?
damages the walls inside them, reducing SA for gas exchange and leading to emphysema
what does tar do to your lungs and trachea?
damages the cilia, which catch dust and bacteria before they reach the lungs and keep the trachea clear. this causes chest infections.
what does tar do to the bronchi and bronchioles?
irritates them, causing mucus to be produced, which the cilia cant clear - causing smokers cough
what does carbon monoxide do to the body?
reduces the amount of oxygen the blood can carry. to make up for this heart rate increases, leading to high blood pressure. this damages artery walls, making the formation of blood clots more likely.
how does tobacco smoke cause cancer?
it contains carcinogens
