8 - Gas Exchange and Respiration Flashcards
What parts of the body are involved in gas exchange? (9)
Lungs, diaphragm, ribs, intercostal muscles, larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries.
What is required of a surface for gas exchange to occur?
Must be permeable, close, thin, have a large surface area, good blood supply and good ventilation with air.
How much oxygen is in inspired and expired air respectively? (explain reasons)
21% and 16% - Oxygen is removed from blood by respiring cells so blood returning to lungs has a lower oxygen concentration than the air in the alveoli.
How much Carbon Dioxide is in inspired and expired air respectively? (explain reasons)
0.04% and 4% - Carbon Dioxide is produced by respiration and diffuses into blood from respiring cells; the blood transports the Carbon Dioxide to the lungs where it diffuses into the alveoli as it is in a higher concentration in the blood than in the air in the alveoli.
How much Nitrogen is in inspired and expired air respectively? (explain reasons)
78% in both - Very stable and can’t be used by the body so concentration remains same.
What is the quantity of water vapour in inspired and expired air respectively? (explain reasons)
Lower and higher - Water evaporates from the alveoli into the expired air as a result of the warmth of the body.
Explain how the limewater is used to test Carbon Dioxide and investigate the differences in composition between inspired and expired air.
When we breathe in, the air is drawn through boiling tube A, when we breathe out, the air is blown into boiling tube B. Lime water is clear but becomes cloudy or milky when Carbon Dioxide is bubbled through it. The limewater in boiling tube A will remain clear, but in tube B it’ll turn cloudy, showing us that the percentage of Carbon Dioxide in exhaled air is higher than in inhaled air.
How does exercise affect breathing? (short)
It increases the frequency and depth of breathing.
How can one investigate the effects of exercise on breathing?
By counting the breaths taken during one minute at rest and measuring average chest expansion over 5 breaths using a tape measure held around the chest.
- Exercise for a set time (at least 3 minutes)
- Immediately after exercising, count the breaths taken in one minute and measure the average chest expansion over 5 breaths
- Following exercise, the number of breaths per minute will have increased and the chest expansion will also have increased
During exercise, how is the Carbon Dioxide concentration affected?
More Carbon Dioxide is produced and enters the blood. As blood flows through the brain, the increase in Carbon Dioxide concentration stimulates receptor cells, which send impulses to the muscles of the lungs, making them contract faster and more strongly. This causes the frequency and depth of breathing to increase till the concentration decreases.
What are ciliated epithelial cells?
The cells have tiny hairs on the end of them that beat and push mucus up the passages towards the nose and throat where it can be removed.
What is mucus and it’s function?
It’s made by goblet cells (because they’re shaped as goblets). It traps particles, pathogens like bacteria or viruses and dust and prevents them getting into the lungs.
What health issues can tobacco smoking cause?
Chronic obstructive pulmonary disease, lung cancer and coronary heart disease.
How does the tar from smoking affect health?
Tar is a carcinogen (substance that causes cancer). Tar can cause emphysema - The alveoli become less elastic and cannot stretch so many burst. The breakdown of alveoli reduces the surface area for gas exchange, causing patients to need a constant supply of oxygen to stay alive. It can also cause Chronic bronchitis - It destroys cilia and the mucus builds up - smoker’s cough is attempt to move the mucus.
How does the nicotine from smoking affect health?
Nicotine is an addictive substance (increases dopamine levels). Nicotine narrows blood vessels, leading to increased blood pressure, and also increases heart rate and leads to hypertension- can cause blood clots to form in arteries leading to a heart attack or stroke.
