Chapter 3: Breathing & Gas Exchange Flashcards
If cells are to respire aerobically they need…
….a continuous supply of oxygen from the blood
Also, was product of respiration is…
….carbon dioxide which needs to be removed from the body
Respiration is…
…the oxidation reaction that releases the energy from foods
The lungs are enclosed by the….
chest (or thorax) and the diaphragm
The air passages of the lungs for a highly branching network known as…
…the bronchial tree
Air comes in down the…
…windpipe or trachea (lined by cartilage to keep aways open)
Air goes down…
bronchus/i…to smaller tubes called bronchioles…to microscopic air sacs called alveoli…where the gas exchange with the blood takes place
The chest/thorax is separated from the lungs by two thin membranes called…
…the pleural membranes…which form an airtight seal (between the two membranes is pleural fluid so lungs dont stick to chest when we breathe)
The trachea and larger airways are lined with…
…mucus which traps dirt of bacteria that are breathed in
Ventilation is…
…action of moving air in and out of lungs
What are the two actions that take place for air to enter into the lungs?
The external intercostal muscles on the ribs contract, pulling ribs up, as do the muscles of the diaphragm, pulling the diaphragm down…causing drop in pressure inside the chest/thorax compared to the air outside
What are the two actions that take place for air to exit the lungs?
The internal intercostal muscles contract pulling ribs down and diaphragm muscles relax…plus as lungs are elastic they help and tend to empty like a balloon
Gas exchange at the alveoli…
….absorbing oxygen into the blood and removing carbon dioxide from it …the distance between the blood & air is less than 1/1000th of a millimetre (blood has come from the body where it gives oxygen to the cells and gains carbon dioxide in return)
What is the number of alveoli & surface area?
700m and 60m2
Smoking related diseases include…
….lung cancer, bronchitis, emphysema & contributes to heart disease and ulcers…dont do it…it’s very bad for you…just say no!
Smoking destroys…
…the cilia in the throat…which means the mucus is not swept away and clogs and irritates the airways and leaves bacteria in the mucus which causes infections
Emphysema
damages walls of alveoli and causes enlarged irregular spaces…meaning reduced gas exchange. Kills about 20,000 people a year in UK
Lung cancer
Cigarette contain addictive nicotine…along with 17+ chemicals (known as carcinogens) which cause cancer Cancer happens when cells start to mutate and divide uncontrollably…forming a tumor Kills around 120,000 people a year
