The oper under si andiriq of applied physiology requires an integrated

dead may persuade the aggressor to leavfl it) Or. it may be an attempt by the Nature td save the victim from the agonies associated with a violent death Respiration tan be altered voluntarily Thus both voluntary hyperventilatmn and voluntary breath holding are possible Impulses for this come horn the cerebral cortex 2. Injuries in the lateral part of the hypothatamus produces a depression ofrespirahon 3. Activities of Ihe limbic system also influence respiration. Limbic system are areas of the bram whose activities produce various emotional changes. Thus, sobbing, which is associaied with a typical respiratory pattern, occurs during grief it should he noted that gyrus cinguh is also a part of the limbic system Mypolhalamus, too is strongly connected with the limbic system The oper under si andiriq of applied physiology requires an integratedconcept of the different chapters A whole chapter has been devoted later in this section and the student is referred to that chapter (chap 6) far understanding the physiological basis of different diseases of ventilation and their management SUMMARY & HIGHLIGHTS Respiration is so adjusted that Ft keeps our bodily 02 need satisfied, dnves out C02 and H+ ions, yet it operates at low cost Further, respiration can take care of the changes of out body needs by altering the frequency [normally about 14/min) and depih (normally 500 ml) of individual excursions and do thai automatically Further, respiratory movements are automatic and rhythmic. These features, viz, automaticfly, rhythmicity and adjusttbiIrty to Ihe needs are dependent on the presence of a respiratory cenler (RC) which receives many feed backs from various parts of the body to adjust according to the needs, medullary (DRG & VRG) The RC consists of { , pontine (apneustic and pneumoiaxic) centers Inspiratory (i) neurons, mostly in the DRG are always active, only the activity regularly increases and decreases When it increases, the RC cenler dischargee ) inspiration begins When decreases, the inspiration stops expiration begins The I neurons are strongly influenced by reflexes (eg, load detecting reflex/Hering Breuer reflex and so on) PaCo2 and so on PaC02 acts mostly via central c h em o receptors (CC) of medulla Al exceptional times, depression of Pa02 becomes an important controlling agent ofE, examples include cor puimonale and high altitude sickness. 02 lack acts wa peripheral chemoreceplor (carotid and aortic bodies) Finally, sometimes, higher cenlers (corrax /hypolhalanuts) appear in the picture of control Cause of rhythmicily is rather speculalwe One such theory has been discussed EXCHANGE OF GASES BETWEEN THE ALVEOLI AND PULMONARY CAPILLARY BLOOD 1. Introduction 2 The Interposrng Membrane (Alveofo Capillary Membrane) 3. Pick's Law, Transfer Factor, DL02 and DLC02. Measuremenl of Diffusion Capacity A. Shunts 5 Applied Physiology 6. Summary Introduction Oxygen passes from the alveoli to the pulmonary capillary blood and C02 is disgorged from the capillary blood to the alveoli In ihis chapter, the mechanism and the factors invoked in such transfers will be discussed The gases,