6.2 Gas Exchange
Explain the role of mucus and cilia in protecting the gas exchange system from pathogens and particles.
- Bronchi in the lungs are lined with cilia cells. 1. Cilia cells line the lungs with hair-like protrusions=Sweep any unwanted microbes or particles out of our lungs and airways. - Scattered in between cilia cells are goblet cells that produce mucus. 1. Trap any unwanted particles, making the job of cilia cells easier. 2. Also protects the cilia cells by lining it with a layer of mucus.
Investigate and describe the effects of physical activity on rate and depth of breathing.
- Exercise and other intense physics activities 1. Increase our rate of breathing 2. Shortens depth of breath.
State the differences in composition between inspired and expired air
- Exhaled air has high levels of CO2 and water vapor - Inhaled air has O2 and very little amount or no water vapor. - Inspired air has around 21% of oxygen - Expired air consists of 17% oxygen.
List the features of gas exchange surfaces in animals
- Gas exchange surfaces are organs that allow the diffusion of gas in and out of the body. - Mammals = lungs. - Specifically, gas exchange takes place in the alveoli. - Key features of gaseous exchange in humans: 1. Walls of alveoli are made from a single layer of cells - allows for gases to easily diffuse in and out of the capillaries. 2. Alveoli have a moist lining - The oxygen dissolves into the moist lining and enters the blood stream. 3. Large surface area - The lungs contain a lot of alveoli, allowing for more gas to be exchanged.
Describe the effects of tobacco smoke and its major toxic components (tar, nicotine, carbon monoxide, smoke particles) on the gas exchange system.
- Tar: 1. Presence of tar in our airways causes MORE mucus to be produced by the goblet cells. 2. Tar paralyzes our cilia cells, meaning that they cannot properly function and remove the mucus. 3. Excess mucus builds up in our airways. 4. Smokers cough more often to shift the mucus to the back of their throats. 5. Clogs up the alveoli in our lungs, reducing surface area for gas exchange to take place=less oxygen entering body. 6. Carcinogen-deposited tar in lungs raises the risk of lung cancer amongst other diseases such as chronic bronchitis. - Nicotine: 1. Presence of nicotine in our bloodstream raises heart bpm, 2. Increases blood pressure by narrowing our blood vessels. - Carbon monoxide: 1. Binds with the haemoglobins in our red blood cells, reducing its ability to carry oxygen around our body. 2. Therefor, it puts more strain our body's respiratory system. - Smoke particles: 1. Smoke particles may also coat the walls of the alveoli, preventing gas exchange from taking place.
Explain the effects of physical activity on rate and depth of breathing.
- When cells become more active, (such as our muscles when we exercise): 1. They need more oxygen in order to perform aerobic respiration to break down glucose and release energy. 2. As a result, we breath faster in order to deliver more oxygen to cells around our body.
Use limewater as a test for carbon dioxide to investigate the differences in composition between inspired and expired air.
between inspired and expired air. - We can use lime water to investigate the difference between inspired and expired air. - Lime water, in the presence of carbon dioxide becomes cloudy. - In ambient air, lime water is clear because the ambient air does not contain a significant amount of carbon dioxide. - However, if you breathe into a solution of lime water, it turns cloudy/milky as the lime water absorbs the carbon dioxide.
