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Passage of air from outside the body to the lungs and gas exchange Respiratory System Passage of air from outside the body to the lungs and gas exchange

Breathing vs Respiration 3 Main Functions: supply oxygen to the blood remove carbon dioxide from the blood regulate blood pH Breathing vs Respiration 3 Types: (movement of gases) -getting air to the lungs External  O2/CO2 exchange in lungs Internal  gas exchange at the tissue level Cellular  utilizing O2 for energy Conductive Zone vs Respiratory Zone

The Conductive Zone Nasal cavity Mouth Pharynx Larynx Trachea Bronchii warm humidfy filter Bronchioles -hairs -mucous

? The Respiratory Zone -video Alveolar sac Respiratory bronchiole Terminal bronchiole Alveolar sacs spread out = tennis court!!!!! gas exchange each sac covered by network of capillaries  short diffusion - grape like structure -HUGE surface area ? Pulmonary vein Pulmonary artery

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

So how do we breath? Diaphragm contracts (moves down) Chest increases in size  air space increases Decrease in pressure in the lungs .: Pressure outside body > inside body Air rushes in 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?

What controls ventilation? Graphically???? What controls ventilation? CNS  medulla oblongata (contraction/relaxation of muscles) -O2 vs CO2 needs Bicarbonate (HCO3) -blood pH (buffer)

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

Gas Exchange (Alveoli) Now what happens with the air in the lungs? Gas Exchange (Alveoli) Respiration Lungs  O2  blood  CO2  Lungs DIFFUSION!! * Read pages 123-124 * Describe partial pressures Explain the 3 factors that contribute to gas exchange Diffusion pathway Barrier thickness Surface area -video

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

Carbon Dioxide Transport Read page 125: Carbon Dioxide Transport and Ventilation and the Regulation of Blood pH Make your own brief notes on: a) The 3 ways in which CO2 is transported in the blood b) The role pH plays in human ventilation