gas exchange Flashcards
what is breathing
the action of taking air into the lungs and sending it out again
what is gas exchange
the process by which oxygen is transported to the cells and carbon dioxide is transported from the cells
define cellular respiration
the release of energy in the form of ATP from food substances in all living things
name the adaptations of leaves for gas exchange
-thin leaf blade for short diffusion distance
-moisture surrounding cells and in leaf for gasses to dissolve in before entering the cells
-large surface area for gas exchange
-pores for good ventilation (stomata)
what is the thorax
the chest
what are some adaptations of alveoli for gas exchange
-thin walls for short diffusion distance
-moist walls for gasses to dissolve helping them pass across the surface
-large surface area as there are many
-dense network of capillaries
explain the steps of breathing in
1-the diaphragm muscles contract pulling the diaphragm down and increasing thorax volume
2-inter coastal muscles contract, pulling the rib cage up and out, further increasing thorax volume
3- as thorax volume increases, pressure inside falls below pressure outside
4- air is drawn in to the lungs
explain the process of breathing out
1- diaphragm muscles relax, decreasing thorax volume
2- inter coastal muscles relax, allowing rib cage to drop and also decreases thorax volume
3- as volume inside decreases, pressure increases, become higher then atmospheric pressure thus forcing the air out
what does nicotine do to the body (smoking)
it is an addictive but harmless drug in tobacco. Nicotine stimulates the brain and relaxes the muscles, but also raises blood pressure and increases fatty substances in the blood causing heart disease
what does tar do to the body
tar is another chemical found in tobacco. It is sticky and black, and often accumulated in the lungs turning them grey. Tar makes smokers more likely to develop bronchitis. Tar build up can lead to breaking down the alveoli, reducing surface area to volume ratio in the lungs, leading to severe breathlessness or death. Tar is also a carcinogen.
Name two diseases caused by smoking
Emphysema and lung cancer
explain emphysema
repeated coughing from smoking can lead to breaking/ tearing alveoli. The remaining alveoli become thicker, leaving the lungs with less surface area available for gas exchange. This leads to permanent disability or eventual death
explain how smoking can cause lung cancer
the tar in cigarette smoke is absorbed by some of the lung cells, specifically the ones lining the bronchi and bronchioles. Normally these form a thin protective layer, however the tar makes them divide and build up into a thick layer. If this continues it can develop into cancer and may spread around the body.
