Lesson # 13

1. Lesson # 13 The Respiratory System 2 Chapter 23 Objectives: 1- To explain the physical principles governing the movement of air into the lungs. 2- To identify the principal measurable pulmonary volumes. 3- To identify the principal pulmonary capacities.

2. External Respiration and Internal Respiration External Respiration O2 CO2 • It is the loading of O2 and unloading of CO2 at the pulmonary capillaries (gas exchange). Alveoli in lung 1. Pulmonary ventilation. • 2. Gas diffusion. Why do we breath? O2 CO2 • 3. Exchange of O2and CO2between the pulmonary capillaries and the alveoli. Cellular Respiration Food Tissue cells CO2 Internal Respiration + O2 O2 It is the unloading of O2 and loading of CO2 at the systemic capillaries. CO2 + CO2 O2 + H2O Food H2O CO2 CO CO O O 2 2 2 2

3. Respiration External Respiration Internal Respiration Pulmonary ventilation O2 transport Tissues Gas diffusion Gas diffusion Lungs Gas diffusion Gas diffusion CO2 transport

4. The Movement of Air Pulmonary Ventilation: It is the physical movement of air into and out of the respiratory tract. PressureChanges during Inhalation and Exhalation Volume Volume Pressure (759 mmHg) Expiration Inspiration -1 +1 Air: 760 mmHg Pressure (761 mmHg) Rib cage in normal position and diaphragm is relaxed Intercostal muscles elevates the rib cage and diaphragm is contracted Boyle’s law: Pressure and volume are inversely proportional

5. 760 mm Hg No flow Inspiration Expiration 760 mm Hg 759 mm Hg 761 mm Hg Intercostal muscles elevates the rib cage and diaphragm is contracted Rib cage in normal position and diaphragm is relaxed Atmospheric Pressure • If the pressure falls below the atmospheric pressure the air moves into the lungs (inspiration). At rest • If the pressure increases over the atmospheric pressure the air moves out the lungs (expiration).

6. The Respiratory Cycle A Respiratory Cycle: It is a single cycle of inhalation and exhalation. 760 mmHg INHALATION A plot of the amount of air moving into and out the lungs during a single respiratory cycle INHALATION EXHALATION +2 Pressure (759 mmHg) Changes in intrapulmonary pressure during a single respiratory cycle. Volume Volume +1 Resting 759 mmHg 0 Pressure (761 mmHg) -1 760 mmHg EXHALATION -2 500 Inhalation Exhalation 250 761 mmHg 0 1 2 3 4 Time (sec)

7. Respiratory Rates and Volumes 1 2 3 4 5 6 7 8 9 10 11 12 Inhalation Exhalation 500 mL Resting tidal volume 1 minute It is the volume of air moved into or out the lungs during a single respiratory cycle under resting conditions. Resting Tidal Volume: Respiratory Rate: It is the number of breath you take each minute. In a resting adult ranges from 12 to 18 breaths each minute. Respiratory Minute Volume: It is the volume of air moved each minute. x Respiratory Minute Volume Tidal Volume = Breath per minute (reparatory rate) x = 6000 mL per minute (6.0 liters per minute) 500 mL 12 per minute

8. Respiratory Performance and Volume Relationships Respiratory Volumes 1- Resting Tidal volume (Vt): It is the amount of air inhaled or exhaled a single respiration cycle under resting conditions (500 mL). 2- Expiratory Reserve Volume (ERV): It is the amount of air that you can voluntarily expel after you have completed a normal, quiet expiration (1000 mL). 3- Residual Volume (RV): It is the amount of air that remains in the lungs after a maximal exhalation (1200 mL). 4- Inspiratory Reserve Volume (IRV): It is the amount of air that you can voluntarily inhale after you have completed a normal, quiet inspiration (3000 mL). 6000 mL Inhalation Exhalation Inspiratory reserve volume (IRV) 3300 mL Resting tidal volume (Vt) 500 mL Volume (mL) Total lung capacity Expiratory reserve volume (ERV) 1000 mL Residual volume (RV) 1200 mL Minimal volume 30-120 mL The amount of air that will remain in the lungs if they were allow to collapse. Time 0 (mL)

9. Respiratory Capacities It is the maximum amount of air that you draw into your lungs after you have completed a normal tidal expiration (Vt + IRV = 3800 mL). 1- Inspiratory Capacity : It is the amount of air remaining in your lungs after you have completed a normal tidal expiration (ERV + RV = 2200 mL). 2- Functional Residual Capacity (FRC): It is the maximum amount of air that you can move into or out of your lungs in a single forced respiratory cycle (ERV + Vt + IRV = 4800 mL). 3- Vital Capacity (IC): It is the total volume of your lungs (vital capacity + RV = 6000 mL). 4-Total lung capacity (TLC): Inspiratory reserve volume (IRV) 3300 mL Inspiratory capacity Vital capacity Resting tidal volume (Vt) 500 mL Total lung capacity Expiratory reserve volume (ERV) 1000 mL Functional residual capacity Residual volume (RV) 1200 mL Minimal volume 30-120 mL Time