Process of Breathing “movement of air from outside the body to the lungs” Diaphragm is the principle muscle in controlling breathing  upon stimulation, will contract

Air outside  Air inside PRESSURE CHANGES High pressure  Low pressure Pleural membrane covers lungs and allows smoother movement

Automatically So how do we breath? Diaphragm contracts (moves down) Chest increases in size (intercostal muscles)  air space increases Decrease in pressure in the lungs .: Pressure outside body > inside body Air rushes in Automatically INHALATION (active process) EXHALATION (passive/active) Diaphragm relaxes Chest decreases in size  air space decreases Increase in pressure in the lungs .: Pressure outside body < inside body Air rushes out Forced breathing Quiet breathing

Ventilation at maximum? Ventilation (VE ) “The volume of air that is moved in 1 minute.” Air in and out VE (L/min)= VT (L) x f (breaths/min) Tidal Volume volume of air in each breath rest = 0.5 L/min max = 3-4 L/min Respiratory frequency number of breaths per minute rest = 12 breaths/min max = 30-40 breaths/min Ventilation at maximum?

Lung Capacity Spirometer Depends on: sex, body type, and lifestyle Spirometer Using your textbook (page 443) label, name and define the 6 short forms above

Lung Volumes TLC = VC + RV Static vs Dynamic So we’ve got the air to the lungs. . . Lung Volumes Static vs Dynamic -volumes determined by structure of lung -volumes dependent on movement of air TLC = VC + RV Total Lung Capacity max air lungs hold Vital Capacity max air exhaled following max inhale Residual Volume remaining air in lungs after max exhale

Oxygen Usage VO2: mVO2 VO2max mVO2 = 15 HRmax HRmin rate at which oxygen is used by the body -measured in mL/kg/min mVO2 VO2max -measure of efficiency of the respiratory system How do we calculate? mVO2 = 15 HRmax HRmin 220-age

O2 Transport 2% dissolved in plasma VAST majority binds to hemoglobin (1.34 ml of O2 per molecule) OXYHAEMOGLOBIN DISSOCIATION CURVE -Percent saturation of hemoglobin (SbO2%) -Pressure of oxygen in the blood (PO2) What does this graph illustrate? The lower the PO2, the less O2 will bind to hemoglobin

Your turn, In your own words discuss what effect ALTITUDE has on respiration. Read page 449 in your textbook to help with your understanding.