2 Small amounts bind to amino groups of plasma proteins 3 Some is dissolved as

2 small amounts bind to amino groups of plasma

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The H+ can affect blood pH and have an effect on rate of respiration. 2. Small amounts bind to amino groups of plasma proteins 3. Some is dissolved as gas in the plasma 3. Respiratory buffers The carbonic acid-bicarbonate buffer system CO 2 + H 2 0 H 2 C0 3 HCO 3 - + H+ Can resist larges changes in pH in the blood very quickly. If CO 2 + builds up in the blood due to shallow or impaired breathing then this equation is pushed to the right side and the body becomes more acidic. This is respiratory acidosis . If large amounts of CO 2 are blown off as in hyperventilation then the pH of the blood rises and this is respiratory alkalosis . Remember that the normal range of plasma pH is 7.35-7.45. The respiratory system/blood plasma buffer works to keep the pH in this range. It is also aided by other buffer systems in the body that we will explore in later chapters. More later. IV. Control of Respiration A. Brainstem Regulators Located in the medulla in the areas known as the dorsal and ventral respiratory centers. These neurons spontaneously become active and then fatigue, setting up the basic rhythm of breathing They send their impulses along the phrenic and intercostal nerves to the muscles of inspiration. Pontine respiratory centers (apneustic, pneumotaxic) - coordinate and regulate the respiratory center to ensure that breathing is rhythmic and even. B. Modifications of rhythmic ventilation Voluntary control - i.e. hyperventilation, voluntary apnea Changes in blood pH, Co 2 levels picked up by chemoreceptors Stretch receptors in lungs respond to over- inflation Emotions 8
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Nur 0013 Painful stimuli Proprioreceptors Chemical or mechanical irritants C. Chemical Control of Respiratory 1. Chemoreceptors are located in the carotid and aortic bodies as well as in the medulla. Peripherals -pick up changes in pH, PCO 2, and PO 2 levels. PCO 2 is most important regulator of rate. Central - due to Blood brain barrier only pick up on pH changes. 2. Chemicals involved in respiratory rate (see buffers above) pH <7.35 = decreased respiration >7.45=increased respiration <7.35 = respiratory acidosis >7.45 = respiratory alkalosis CO 2 Increased in blood (peripherals) = increased RR. Increased CO2 in blood is picked up as an increase in H+ ions in the CSF = increased RR Very important regulator of rate O 2 Large decrease will change rate, but not small changes because of hemoglobin’s ability to release greater amounts of oxygen. Clinical – In patients with advanced chronic obstructive lung disease levels of CO 2 are chronically elevated and the body begins to use levels of O 2 to regulate breathing. Giving these people more O 2 will actually decrease their respiratory rate. 9
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