Ventilation!

1. Ventilation!

2. What are the two main functions of the respiratory system? • VENTILATION • RESPIRATION • Today’s topic is PULMONARY VENTILATION (a.k.a. breathing)

3. So, what is breathing? • Movement of air from outside the body into and out of the bronchial tree and alveoli • Inspiration (inhalation)- air flowing into lungs • Expiration (exhalation) – air leaving lungs

4. Bellwork (well after the bell…) • Particles move from areas of concentration to areas of concentration. • What is air pressure or atmospheric pressure? • What causes hiccups? • What is the purpose of yawning?

5. The FORCE behind breathing • ATMOSPHERIC PRESSURE! • Rules of thumb: • Volume changes lead to pressure changes • Volume (V) and pressure (P) are inversely related • As volume decreases, pressure increases • As volume increases, pressure decreases. • Gases flow from areas of high pressure to areas of low pressure

6. Steps of Inspiration • Diaphragm and intercostal muscles contract • Thoracic cavity increases • Volume of lungs increases • Pressure within lungs decreases • Air enters lungs

7. Steps of Expiration • Inspiratory muscles relax • Volume of thoracic cavity and lungs decreases • Pressure in lungs increases • Gases flow out of lungs

8. Compare and Contrast

10. Misc. ventilation air movements (Thanks to reflexes!) • Cough: clear lower respiratory passages • Sneeze: clear upper respiratory passages • Crying: emotional response • Laughing: emotional response • Hiccups: spasms of diaphragm causes air to strike vocal cords. What’s the function of hiccups? Don’t know. • Yawn: ventilates all alveoli in response to low blood oxygen concentration

11. Respiratory Air Volumes and Capacities • Factors affecting lung capacity • Size • Sex • Age • Physical Condition • Lifestyle choices

12. Respiratory Volumes • Respiratory volumes: four different volumes of air that move in or out of the lungs based on breathing intensities • Respiratory cycle: one inspiration plus the following expiration

13. How much air do you think moves in and out of your lungs when you breathe normally?

14. Respiratory Volume and Capacities • Tidal Volume • Amount of air moved in and out during normal breathing (one cycle) = 500 ml or a pint • Inspiratory Reserve Volume • Amount of air that can be taken in with force (deep breath)= 3,000 ml

15. Respiratory Volume and Capacities • Expiratory Reserve Volume • Amount of air that can be forcibly exhaled after a tidal expiration or in addition to the tidal expiration = 1200 ml • Residual Volume • Air that cannot be voluntary expelled and remains in lungs to keep gas exchange continuous (1200 ml)

16. TRY TO BREATHE ALL THE AIR OUT OF YOUR LUNGS! • Oops. You can’t! This is because there is always a… • Residual Volume • Air that cannot be voluntary expelled and remains in lungs to keep gas exchange continuous = 1200 ml

17. Pulmonary Ventilation:Respiratory Volume and Capacities • Vital Capacity (VC) • Maximum amount of air a person can exhale after taking the deepest breath possible (4800 ml) • Tidal volume + inspiratory reserve + expiratory reserve • VC = TV + IRV + ERV • Total lung capacity • Vital Capacity + Residual volume

18. Alveolar Gas Exchange

19. Bellwork (round 2!) • What is air made of? • Gases move from (high/low) pressure to (high/low) pressure. • Describe what simple squamous cells look like. • What is respiration?

20. Respiratory Membrane: Structure • Respiration: process of gas exchange between the atmosphere and the cells • Wall of the alveoli are made of simple squamous cells • Respiratory membrane: squamous epithelial cells 2 cell layers thick that separate air in the alveolus from blood in the capillary • Contains basement membranes and cartilage

21. Respiratory Membrane: Function • What is the function of the respiratory membrane? • Hint: What is respiration? • Function: Diffusion of gases • Gases move from pressure to pressure. • The pressure of a gas determines its rate of diffusion

22. Atmospheric/Alveolar Partial Pressure • So what gases do we breathe? • 78% Nitrogen • 21% Oxygen • .04% Carbon Dioxide • Atmospheric pressure is 760 mm Hg • Each gas in the atmosphere/alveoli has a partial pressure • PO2 = 760 mm Hg * .21 • PCO2 =

23. When gases are dissolved in liquid, the concentration (or amount) of each gas is proportional to the partial pressure PO2 = 40 mm Hg PCO2 = 45 mm Hg Partial Pressure in Blood

25. Given the differences in pressure which direction will each gas move? • CO2 moves into the alveoli • O2 moves into the capillaries • The blood that is delivered to the tissues has these partial pressures: CO2 = 40 mm Hg, O2 = 104 mm Hg

26. Steps of RESPIRATION (gas exchange between atmosphere and cells) • Ventilation • Gas exchange between blood and air in the alveoli  external respiration • Gas transport in blood between lungs and body cells • Gas exchange between blood and body cells  internal respiration

27. Review (These are really important points!) REALLY IMPORTANT POINTS ABOUT GAS EXCHANGE: • Describe the structure of the respiratory membrane. • How does this structure allow it to perform its function? • Oxygen diffuses from the to the .

28. Review (These are really important points!) REALLY IMPORTANT POINTS ABOUT GAS EXCHANGE: • Carbon dioxide diffuses from the to the . • What force moves oxygen and carbon dioxide across the respiratory membrane? • The large surface area of alveoli increases the rate diffusion across the respiratory membrane.

29. A. OXYGENIII. O2 transport in blood between lungs and body cells • Once O2 crosses the respiratory membrane in the lungs, it binds to an iron-containing protein in red blood cells called hemoglobin • “heme” = iron • Globin = type of protein • http://www.nytimes.com/imagepages/2007/08/01/health/adam/19510Hemoglobin.html

30. A. OXYGENIII. O2 transport in blood from lungs to body cells • Bound to hemoglobin, blood delivers O2 to body cells

31. A. OXYGENIV. O2 exchange between blood and body cells • As O2- carrying blood moves from the lungs (PO2 = 95 mm Hg), the surrounding oxygen-depleted tissues have a very low PO2 (40 mmHg) • O2 diffuses from (blood/tissues) to (blood/tissues). • After O2 diffuses, PO2 in blood returning to the lungs is 40 mmHg

32. B. CO2IV. CO2 exchange between body cells and blood • The PCO2 in tissues is 45 mm Hg while the PCO2 in blood is 40 mm Hg • Thus, CO2 diffuses from (tissues/blood) into (tissues/blood) • The blood returning to the lungs has a PCO2 of 45 mmHg

33. B. CO2III. CO2 transport from body cells to lungs • CO2 is transported in blood as • CO2 dissolved in the plasma • Bound to hemoglobin • As bicarbonate (HCO3-) ion • Wait, isn’t O2 bound to hemoglobin? How can hemoglobin bind both molecules? • Different binding sites • Difference in PCO2 at lungs allows CO2 to diffuse from blood to lungs

34. Note to Mr. Bell: Pass out notecards for pop test!!

35. Reading Test! Write your name, date, and period on the index card and answer these questions. • The protein in blood that transports oxygen from lungs to cells is called . • Name one form in which blood can transport carbon dioxide from cells to the lungs.

36. Reading Test! Write your name, date, and period on the index card and answer these questions. • A deficiency of oxygen reaching the body tissues is called . • Name one form in which blood can transport carbon dioxide from cells to the lungs.