BIOL 460 1st Edition Lecture 28 Outline of Last Lecture I Boyle s Law II Spirometer III Lung Diseases a Restrictive b Obstructive IV Gas exchange in Lungs Outline of Current Lecture I Starling s Forces II Regulation of Breathing III Chemoreceptors a central b peripheral c Hypoventilation d Hyperventilation Current Lecture 1 Starling s Forces a Fluid out fluid in BF b Different in pulmonary circuit c BF deltaP R d deltaP 15mmHg 5mmHg 10 mmHg 10 of systemic circuit e Resistance must also be 10 of systemic resistance f Pulmonary low pressure low resistance g 15 0 1 25 11mmHg h 5 0 1 25 21mmHg i Negative indicates inward component is greater more fluid in than out fluid moves from alveoli to blood These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute j If either was positive as in pulmonary hypertension it would cause pulmonary congestion due to failure of L ventricle k Heart attack can cause pulmonary edema accumulation of fluid in lungs fatal in 30 minutes l Systemic Circuit Reactive hyperemia due to Co2 increase which causes pH drop causing vasodilation m Pulmonary arterioles vasodilation with high O2 low CO2 basic pH sends blood to better parts of lungs more diffusion at these parts 2 Regulation of breathing a Brainstem respiratory centers send axons to somatic motor neurons in spinal cord which supply breathing muscles b Responsible for automatic control of respiratory rate c Rhythmicity Area in Medulla Oblongata d Inspiratory Neurons somatic motor neurons for inspiratory muscles e Expiratory Neurons somatic motor neurons for expiratory muscles less important f Have HCN channels generate action potentials at a certain pace g Inspiratory neurons stimulate somatic motor neurons with an EPSP h Expiratory neurons stimulate somatic motor neurons with an EPSP i Inspiratory neurons and expiratory neurons create IPSPs for each other j Most expiration due to elastic recoil k When one fatigues the IPSP is inactive l For respiratory centers to control respiration rate they must have sensory input 3 Chemoreceptors a Central i Medulla ii Long term changes in respiratory rate b Peripheral i Aorta ii Carotid Sinus behind earlobe iii Short term modifications c Much more sensitive to CO2 than O2 i Hypoventilation 1 Quick increase in CO2 hypercapnia above 40mmHg 2 Slow decrease of O2 ii Hyperventilation 1 No change in ppO2 2 Amount of CO2 decreases dramatically hypocapnia below 40mmHg iii Respond to CO2 levels indirectly 1 Senses carbonic acid 2 CO2 H2O H2CO3 H HCO3 3 Makes pH more acidic 4 Chemoreceptors respond to drop in pH iv Set to maintain ppCO2 of 40mmHg in blood v Figure 16 29 H cant cross blood brain barrier CO2 crosses then converted to carbonic acid in interstitial fluid of brain
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