Slide 1Slide 2Respiratory System (Å&R, Ch.5)AlveoliMechanics of RespirationLung Volume ChangesVentilation (Minute vs. Alveolar)Slide 8Ventilation/Perfusion ControlTransport of Blood GassesIE 5531IE 553 Engineering of Human WorkDr. Andris FreivaldsClass #24IE 5532IE 553 Engineering of Human WorkDr. Andris FreivaldsClass #24IE 5533Respiratory System (Å&R, Ch.5)•Respiration:–Whole body gas exchange–Cellular metabolism•Respiratory system:–Trachea–Two bronchii & lungs–23 levels of bronchioles–Ending at alveoliIE 5534Alveoli•Gas exchange with capillaries•Overlayed with capillaries•Surface area = 70 m2IE 5535Mechanics of Respiration•Inspiration:–Diaphragm shortens–External intercostals contract, lift ribs•Expiration–Elastic recoil effect of diaphragm–Internal intercostals contract, lower ribs–Abdominals contributeIE 5536Lung Volume ChangesForced expiratory volume= % exhaled in 1 sec (>80%)IE 5537Ventilation (Minute vs. Alveolar)Minute Ventilation (ml/min)Frequency (Breaths /min)Tidal Volume (ml)Dead space (ml)Alveolar Ventilation (ml/min)6,000 40 150 150 06,000 12 500 150 4,2006,000 6 1,000 150 5,100Minute ventilation (VE)= Freq x Tidal volAlveolar ventilation = Freq x (Tidal vol – Deadspace)IE 5538Transport of Blood GassesIE 5539Ventilation/Perfusion ControlBronchioles ArteriolesConstriction ↓CO2, histamine ↓O2, ↑H+Dilation ↑CO2, epinephrine ↑O2 , ↓H+•Small airflow & large blood flow–↑CO2 (bronchiolar dilation) → larger airflow–↓O2, ↑H+ (arteriolar constriction) → smaller blood flow• Large airflow & small blood flow–↑O2 (arteriolar dilation) → larger blood flow–↓CO2 (bronchiolar constriction) → smaller airflowIE 55310Transport of Blood Gasses•Transport of O2: RBC & plasma → muscle –oxyhemoglobin (99%)–dissolved in water (1%)•Transport of CO2: muscle → RBC & plasma–carbonic acid (buffering system, 81%)–carbamino hemoglobin (11%)–dissolved in water (8%)Muscle cell Interstitial fluid Plasma &
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