1 / 14

6.4 Gas Exchange

6.4 Gas Exchange. 6.4.1 Distinguish between ventilation , gas exchange and cell respiration . Ventilation - The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli (the tiny air sacs in the lungs).

kipling
Download Presentation

6.4 Gas Exchange

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 6.4 Gas Exchange

  2. 6.4.1 Distinguish between ventilation, gas exchange and cell respiration. Ventilation - The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli (the tiny air sacs in the lungs). Gas exchange- The primary function of the lungs involving the transfer of oxygen from inhaled air into the blood and the transfer of carbon dioxide from the blood into the exhaled air. And also the exchange of gases that occurs between the blood and the cells. Cell respiration– creation of ATP from the metabolic breakdown of glucose occurring in all living cells.

  3. Check for understanding………. Between the Lungs and atmosphere To keep the air in the lungs fresh (with hi O2 and low CO2 concentrations) so that Gas exchange can take place more quickly. Between the alveoli of the lungs and blood cells. And between the blood cells and the body cells So that the body cells can be provided with O2 from the air and remove CO2to the air so that cellular respiration can take place. To make glucose into useable energy in the form of ATP. In all living cells

  4. Some names to be familiar with…. http://www.daviddarling.info/images/bronchus.gif

  5. 6.4.2 Explain the need for a ventilationsystem. A ventilation system is needed to maintain high concentration gradients in the alveoli. Remember diffusion……. If we replace the blood in the capillary with fresh blood the diffusion gradient will come back…… Initially the O2 is at high concentration in the lungs and CO2 in the blood. By diffusion the molecules move from areas of high concentration to areas of lower concentration. But now no diffusion can happen because there is no diffusion gradient… … and if we replace the air in the alveolus it will also bring a diffusion gradient back Blood capillary of lung We do both! Alveolus of lung Oxygen molecules above even conc. Carbon Dioxide molecules Above the even conc.

  6. 6.4.3 Describe the features of alveoli that adapt them to gas exchange. Alveolus Terminal Bronchiole

  7. Look at the alveolus in detail…. Features: 3. The circular shape gives maximum surface area to volume ration 4. There are mucus secreting glands to keep it disease free and moist. 1 . Closely associated with very good blood supply (in and out) with a capillary bed. 2. There are lots of them giving a very large surface area. http://upload.wikimedia.org/wikipedia/commons/thumb/4/46/Alveolus_diagram.svg/418px-Alveolus_diagram.svg.png

  8. In even more detail……. Having thin walls on both the capillary and the alveolus means there is less distance for the Oxygen and the Carbon Dioxide to have to diffuse across. The film of moisture also makes the diffusion from the blood to the air easier Look at the thickness of the cells around the capillary and around the alveolus…. What is it about them that makes diffusion easy? http://images.tutorvista.com/content/respiration/alveolus-of-man.jpeg

  9. 6.4.4 Draw and label a diagram of theventilation system, Click on this smiley face to check you’ve learnt the labels:

  10. Where are the alveoli in the lungs? IB sylabus point: Students should be able to draw the alveoli in an insetat a higher magnification within the diagram of the ventilation system http://www.patient.co.uk/images/I62_L.JPG

  11. 6.4.5 Explain the mechanism of ventilation of the lungs

  12. If the diaphragm contracts what happens to: • The volume of the thorax? • The pressure of air in the thorax? If the ribs are raised by contracting the Intercostal muscles what happens to: • The volume of the thorax? • The pressure of the air thorax?

  13. Breathing in: 1. 2. 3. 4. 5. 6. Check for understanding…… • Air flows into the lungs from outside. • This movement of the diaphragm decreases the volume of the thorax. Put these sentences in the correct box and order; • This movement of the diaphragm increases the volume of the thorax. • Air flows out from inside the lungs. • The change in volume of the thorax causes the air pressure in the lungs to decrease. • The change in volume of the thorax causes the air pressure in the lungs to increase. Breathing out: 1. 2. 3. 4. 5. 6. • The intercostal muscles contract pulling the ribs upwards and outwards. • The intercostal muscles relax letting the ribs fall down and inwards. • The diaphragm contracts pulling the floor of the thorax downwards. • This movement of the ribs increases the volume of the thorax. • This movement of the ribs decreases the volume of the thorax. • The diaphragm relaxes allowing the floor of the thorax upwards

More Related