Therefort these fluids cannot and do not stimulate the CC cell In short

respiretoary stimulation 3 However, if the P CQ2 of the brain capitary blood remains persistenly high (- exite of excessCQ2 from the blood to CSF or brain tissue fluid is persistenlyy high), same compenatory changes occur liding to regaining of the anginal ph of the CSF thus CSF is no longer acid and it no longer stimulates the CC in l practice. a drammatice example is very advanced case of emphiysema In such case, blood PC02 rremember persistently high but the pH of C5f (and presumably of the bram tissue fluid) remains alkalin Therefort these fluids cannot and do not stimulate the CC cell In short. these patints have high Pa CO2 (and also PA CO2). but the high PaC02 deos not stimulated the respiration yet, for his survivai.the patient requires increased respiratory drive (otherwise he will die of CO2 narcosis) This increased drive cornes from the concomitantl hypxia presenet in such casses. The ultimate conclusion is. inspite of the presented hy poxia in sush cases over enthusiatic correction of hypoxia (by O2 therapy) can kill the patientas as it extingushes the only respiretory stimulus available in this patent Recent wotks indicate that theCC cells are present. in the ventral surfaca of the in three areas. termed tostral, intermidiate and caudal areas. They are also known by their alternate names, viz. areas Mitchell (M). Schlafeke (S) and Loeuhke (L) respectively C02 can also stimulate the respiratory center (RC) via the peripheral chemoreceptares. see bellow. Role ofOxygen What happens in 02 lack (hypoxia) and 02 excess? Between them 02 lack ib much much important and will be described frist . Effects of 02 lack A moderate fall of PI02 (02 tension of inspised air) or PI02 (02 tension ofarterial blood) unlike those with C02, has no appreciable effec evenslight rise of PIC02 or PaC02 causes sharp rise ofE However gross fall ofPl 02 (or concenitration of 02 in the inspired air)leads to sharp rise of Vg which thut Causes correction of the hypoxia