Breathingpractical class lung ventilation lung perfusion ventilation perfusion

Breathing_practical class ? lung ventilation ? lung perfusion

ventilation perfusion

Ventilation Minute ventilation = breath frequency x air volume (balanced) spontaneous ~15 x ~ 500 ml = 7, 5 -8, 0 L/min maximum ~ 150 L/min Minute ventilation is influenced by * p. CO 2 in arterial blood (central receptors - influence rate of firing of neurons in respiratory centers in medula - exciting other portions of respiratory center (dorsal respiratory, ventral respiratory, pneumotaxic, etc. ) CO 2 + H 2 O -> H+ + HCO 3 - *p. O 2 - periphery receptors (aortic, carotid bodies) - only when p. O 2 decreases from 100 mm. Hg to 60 mm. Hg * Temperature - diffusion rate Low p. H -> increased expiration of CO 2 -> regulation of p. H

Ventilation vs. body load Minute ventilation = frequency x volume (balanced) spontaneous ~15 x ~ 500 ml = 7, 5 -8, 0 L/min maximum ~ 150 L/min constant metabolic activity - constant amount of CO 2 expired amount of expired CO 2 = volume x p. CO 2 (concentration) VE (ml/min) V 1 body load V 2 1 2 p. CO 2 The same amount of CO 2 is possible to expire by increased ventilation and low concentration or low ventilation and high concentration All CO 2 produced by body has to be expired, so insufficient ventilation leads to hyperkapnia (high p. CO 2) Body load - O 2 consumption => alveolar ventilation or alv p. CO 2 -> breathing stimulant => lung ventilation

Consumption of O 2 during load Maximal O 2 uptake (VO 2 max)- the highest rate at which oxygen can be taken up and used by the body during severe exercise (ml/kg/min or L / min - absolute uptake) Mean value of VO 2 max : Regular population: men cca 45 ml/kg/min, females 35 ml/kg/min (normal) Top sportsmen (appropriate training): men more than 78 ml O 2/kg/min, females over 68 ml O 2/kg/min Lactate - concentration 0, 5 -2, 2 mmol/L in human body (no load) Amount of lactic acid in blood during intensive work load depends on the type of metabolism (system used for energy production): < 2 mmol/l aerobic (slow glycolysis, oxidative metabolism) 3 – 7 mmol/l aerobic-anaerobic (slow - fast glycolysis) > 7 mmol/l anaerobic (fast glycolyses, glycogene system)

lactate Dynamic of load indicators during excercise Anaerobic zone Aerobic-anareobic zone Aerobic zone load (W) VO 2 max - maximal O 2 uptake, SF- cardiac frequency, ANP - anaerobic threshold, KR - critical intensity of a load

Respiratory quotient (RQ) = CO 2/O 2 expired CO 2 /inspired O 2 CO 2 output / O 2 input RQ depends on the intensity of the work RQ gives an information about food composition (type of metabolism used for energy): oxidation 1 molecule of glucose (C 6 H 12 O 6) requires 6 molecules of O 2 - 6 molecule of CO 2 released =>RQ = 1 Feat acids (lactic acid)- oxidation of 6*CH 2 (C 6 H 12) - requires 9 mol. O 2 - 6 CO 2 released =>RQ = 6/9 Respiratory quotient /different kind of metabolism: RQ metabolism 1, 0 sacharides 0, 9 sacharides-fats 0, 8 fats-sacharides 0, 7 fats

Time course of RQ during heavy work load RQ = CO 2/O 2 3 phases: a) initial increase (greater anaerobic glycolysis, increased formation of lactate) b) secondary drop (slower anaerobic glycolysis -increased O 2 supplytemporary more lactic acid eliminated than formed) c) a continuous rise to a steady state (after approx. 3. 5 -4 min) (correlation with lactic acid level in the blood) If consumption of O 2 is 50% to 60% of VO 2 max (trained persons 70 -80%) - anareobic metabolism take place, lactate in the blood increases during excercise (H+, p. H…) CO 2 HCO 3 - D RQ represents the percentual participation of anaerobic glycolysis in the total energy expediture RQ is over 1 at heavy work loads

1. Spiroergometry the aim -to understand why the R. Q. during physical stress changes. expired CO 2 /inspired O 2 The Gas Analyzer has an infra-red transducer to measure CO 2 concentration and a visible spectrum transducer to measure oxygen concentration Spirometer and attached flow head together function as a pneumotachometer, with an output signal proportional to the airflow rate during breathing. the load on the bicycle ergometer increase in a step-wise manner. Questions 1. Which factors influence the respiratory quotient? 2. Explain differences in R. Q. during normal ventilation and higher physical exercise.

2. Spirometry The aim -to understand p. CO 2 and minute ventilation dependence. Spirometer and attached flow head together function as a pneumotachometer Expired or inspired air passes through a very fine wire mesh in the flow head. This creates a pressure differential between the two sides of the mesh proportional to the flow rate of the air passing through the flow head. Volume x respiratory rate = Minute Ventilation integration of expiratory flow gives the volume. Questions 1. Explain why during hyperventilation CO 2 at the end of expiration decreases? 2. Explain the differences between changes of CO 2 in hyperventilation and in increased minute ventilation as a result of physical exercise. 3. How does CO 2 output change during the test?