Ppt respiratory gas transport powerpoint presentation. How many points on the curve can you indicate with values. P o 2 is plotted on the xaxis from 0 to 100 mm hg millimeters of mercury. More than 100 such abnormal hemoglobins have been described. The oxyhemoglobin dissociation curve is an important tool for understanding how our blood carries and releases oxygen. P 50 is po 2 at which hemoglobin is 50% saturated p 50 v hemoglobin affinity for o 2. Haemoglobin, an allosteric protein, consists of four protein globin chains, to each of which is attached a haem moiety, an ironporphyrin compound. Hemoglobino2 affinity p50 testing oxygen dissociation, p50, erythrocytes among the rare causes of polycythemia is hereditary polycythemia due to the presence of a high o 2 affinity hemoglobin. Gas hydrate phase equilibrium curve gas hydrate prediction curve gas hydrate dissociation curve is a plot of hydrate forming temperature vs. Download translated sbml version of model if available. This is an additional feature of the toxicity of co.
Pulse oximetry and the oxyhemoglobin dissociation curve. The reaction also causes the color of the rbcs in the vial to change from purple to red as shown in the animation. The effects of errors of measurement in oxygen tension and saturation are considered using the technique of sensitivity analysis. The presence of cohb also shifts the o2 dissociation curve to the left, thus interfering with the unloading of o2. Dissociation oxygen transport and dissociation curve clinical psychotherapy trauma dissociation dr rachel thomas. A free powerpoint ppt presentation displayed as a flash slide show on id. Hemoglobino2 affinity p50 testing oxygen dissociation. Figure 2 compares the oxygen binding properties of llama, fetal and maternal human hemoglobin. Concentration of o2hb and hhb allows so2a to be deduced see equation 1. Erythrocytes carrying o2hb then circulate in the blood and release. The oxygen dissociation curve is the expression of the relationship between the partial pressure of oxygen and oxygen saturation of haemoglobin. Decoding the oxyhemoglobin dissociation curve american nurse.
Bird blood has a lower affinity for oxygen than the blood of man, but the form of the oxygen dissociation curve is much the same. An important feature of the oxygen hemoglobin relationship is the manner in which the dissociation curve steepens as arterial p o 2 falls below 60 mm hg. Although the whole curve is the best representation of hemoglobin oxygen affinity, p50 is often used as the sole descriptor. In the lungs, where partial pressures of o2 are high, o2 binds to hemoglobin to form o2hb. Oxygen dissociation curve can you draw the oxygen dissociation curve of normal adult haemoglobin. Curve is leftshifted relative to human hb so as to facilitate diffusion of oxygen. If the instrument for measuring the hemoglobin oxygen dissociation curve is not available, one can estimate the hemoglobin affinity for oxygen by measuring the partial pressure of oxygen, the oxygen saturation of hemoglobin, and the ph from venous blood gases, not arterial blood gases. Comparison of average oxygen dissociation curves based on measured arterial blood. Medcram medical lectures explained clearly 684,442 views. In a study of 3524 clinical specimens, we found that this equation estimated the so2.
Hemoglobin and myoglobin oxygen binding curve explanation part 2. Table iii gives dissociation data in a salt solution, theories of the oxygen dissociation curve. The oxygen dissociation curve of adult haemoglobin is a sigmoid curve. Another mechanism capable of ameliorating oxygen delivery to the tissues in case of hypoxia is a shift in the oxygen dissociation curve. The oxygen dissociation curve shown in figure 712 is sigmoid shaped because of hemeheme interactions. Chemeketa community college oxygen hemoglobin dissociation curve oxyhemo curve the ability of oxygen to bind with and dissociate from hemoglobin how shifts change. Haemoglobin and the oxygen dissociation curve 1, 57.
The oxyhemoglobin dissociation curve ohdc indicates the relationship between the oxygen saturation of hemoglobin sao 2 and the partial pressure of arterial oxygen pao 2. This curve is an important tool for understanding how our blood carries and releases oxygen. This interactive tutorial demonstrations carbon monoxide association with hemoglobin is directly related to the plasma partial pressure of co. Hill and kelman hbo2 dissociation curves the nsr physiome. Oxygen hemoglobin dissociation curve all medical stuff. Details of this relationship and the physiological importance of changes in this relationship were worked out in detail at the beginning of the last century by the great physiologists hufner, bohr, barcroft, henderson and many others.
Equations have been developed to calculate p, from. The oxygen dissociation curve has a sigmoid shape because of the cooperative binding of oxygen to the 4 polypeptide chains. Oxygen hemoglobin dissociation curve is the curve that describes the increase in the percentage of hemoglobin bound with oxygen as blood partial pressure of oxygen increases. This graph shows how changes in the partial pressure of oxygen p o 2 influence oxygen o 2 binding to, and dissociation from, hemoglobin hb. Although patients may have a similar percentage of hemoglobin effected sic as patients with methemoglobinemia, patients with sulfhemoglobinemia have less severe clinical symptoms because of the difference in their effects on the oxygen dissociation curve. Oxygenhemoglobin dissociation curve how ph affects.
Cooperative binding means that haemoglobin has a greater ability to bind oxygen after a subunit has already bound oxygen. The sigmoid shape of the oxygen dissociation curve is a result of the cooperative binding of oxygen to the four polypeptide chains. The alveolar gas equation allows us to predict a parallel rise in pao2 with supplemental o2. The oxygenhaemoglobin dissociation curve, also called the oxyhaemoglobin dissociation. Pulmcrit top 10 reasons pulse oximetry beats abg for. Oxygen conductance from environment to tissues is regulated by such mechanisms as blood flow and hemoglobin concentration which have established importance. Oxygen, dissociation and ph researchgate, the professional network for. An oxyhaemoglobin dissociation curve odc quantifies the most important function of red blood cells and that is the affinity for oxygen and its delivery to the tissues. Oxygen hemoglobin dissociation curve sigmoidal shape is characteristic of positive cooperativity. Multiple factors can affect the affinity of hb for oxygen, thus causing the curve to shift to the left increased oxygen affinity or to the right decreased o2 affinity. Neither linear nor static, the curve can change or shift depending on various factors. Physiology of oxygen transport bja education oxford.
Oxyhemoglobin dissociation curve right left shift explain. This is called the normal oxyhemoglobin dissociation curve. Configuration of the hemoglobin oxygen dissociation curve. Introduction the oxygen hemoglobin dissociation curve plots the proportion of hemoglobin in its saturated form on the vertical axis against the prevailing oxygen tension on the horizontal axis important tool for understanding how blood carries and releases oxygen 4. Oxygen affinity for haemoglobin plays a critical role in the delivery of oxygen to the tissues and is.
Hills equation relating oxygen tension, saturation and p 50 is used as the basis for a simple method to calculate p 50 from a single blood sample. The oxyhaemoglobin dissociation curve deranged physiology. Definition there is a relationship between the amount of oxygen dissolved in the blood and the amount attached to the hemoglobin. Partial pressure is an important aspect of the binding of oxygen to and disassociation from heme. By administering supplemental oxygen or placing a patient in a hyperbaric chamber, the oxygen level can be increased considerably.
Oxygen is carried in the blood bound to haemoglobin and dissolved in plasma and intracellular fluid. The oxygen dissociation curve odc describes this relationship graphically. Google scholar see all references the partial pressure of oxygen dissolved in the plasma is measured as the pao 2. Oxygenhemoglobin dissociation curve how co affects oxyhemoglobin saturation. The oxygen hemoglobin dissociation curve also called the oxyhemoglobin dissociation curve or oxygen dissociation curve odc, is a curve that plots the proportion of hemoglobin in its saturated oxygen laden form on the vertical axis against the prevailing oxygen tension on the horizontal axis. From the above figure, it can be observed that the oxygen disassociation curve for both ph produces same type of sigmoid curve.
The programmable pocket calculator offers advantages of small size. Cassels, melba holder, edna oconnell, and axel swanson department of pediatrics, university of chicago clinics, chicago. This curve may shift to left or right depending upon various factors which are described here. It depicts the relationship between partial pressure of oxygen and percentage saturation of hb. Oxygen dissociation curve an overview sciencedirect topics. The three main points to indicate on the curve are. The shape of the oxygen dissociation curve of hb is sigmoidal, whereas that of other oxygen carrying molecules such as myoglobin is hyperbolic. This curve describes the changing affinity of haemoglobin for oxygen which occurs with increasing pao 2. This curve describes the relationship between available oxygen and amount of oxygen carried by hemoglobin. Top 10 reasons pulse oximetry beats abg for assessing oxygenationi need to acknowledge my debt to josh farkas for getting me thinking about many of these issues 3 years ago in this wonderful post.
Oxygen dissociation curves vary with species and circumstance. The oxygen dissociation curve shows the relation between spo 2 and pao 2. Specifically, the oxyhemoglobin dissociation curve relates oxygen saturation so 2 and partial pressure of oxygen in the blood po 2, and is determined by what is called hemoglobins affinity for oxygen, that is, how. Oxyhemoglobin dissociation curve calculated using a simple hill equation and. Class, notice how with exercise the oxygen hemoglobin curve shifts to the right. When the patient is cold, your tissues need less oxygen, so the hemoglobin has a higher affinity for oxygen, so the curve shifts to the left. See also the interactive oxyhemoglobin dissociation curve that does take into. Diagnosing or ruling out polycythemia vera in patients. An analogous situation the to in curves the of blood 4 in of dissociation subjects. Understanding the oxygen dissociation curve medical exam. Oxygen transport by blood is also influenced by the oxygen affinity of hemoglobin, as defined by the shape and position of the oxygen hemoglobin dissociation curve. Haemoglobin is, therefore, most attracted to oxygen when 3 of the 4 polypeptide chains are.
Llamas adapted to low o 2 conditions at high elevations. The oxyhemoglobin dissociation curve the oxyhemoglobin dissociation curve displays the relationship between the oxygen tension of blood and the oxygen saturation figure 1. The vertical axis is sao2, or the amount of hemoglobin saturated with oxygen. The horizontal axis is pa02, or the amount of oxygen available. The haemoglobinoxygen dissociation curve describing the relationship. Oxygen dissociation curve in normal position 378c, ph 7. Yet understanding the curve and its implications for patient care can be challenging. An oxygen hemoglobin dissociation curve is a graph that describes the relationship of partial pressure to the binding of oxygen to heme and its subsequent dissociation from heme figure 2.
Only the sigmoidal curve is characteristic of the cooperative process by which the release of one oxygen molecule alters the affinity for the. Carbon monoxide poisoning occurs when carbon monoxide binds with hemoglobins four heme groups. The oxygen haemoglobin dissociation curve, also called the oxyhaemoglobin dissociation curve or oxygen dissociation curve odc, is a curve that plots the proportion of hemoglobin in its saturated oxygen laden form on the vertical axis against the prevailing oxygen tension on the horizontal axis. The oxygen dissociation curve odc of hemoglobin hb has been widely studied and. Once the pao2 reaches 60 mm hg the curve is almost flat, indicating there is little change in saturation above this point.
See also the interactive oxyhemoglobin dissociation curve that does take into account temperature and ph. Algorithm for computing oxygen dissociation curve with ph, pco2, and co in sheep blood. The flat upper plateau decreases variability in blood oxygen content even with large changes of pao 2. The rightward shift allows for easier oxygen unloading in the tissues. This figure presents the oxygen disassociation curve of hb at ph 6. Pdf algorithm for computing oxygen dissociation curve with ph. Numerous mathematical models have been designed to predict with everincreasing accuracy the behavior of oxygen transport by hb in differing conditions of ph, carbon dioxide, temperature, hb levels, and 2,3diphosphoglycerate concentrations that enable their. An spo 2 greater than 95% correlates to the normal range of pao 2, which is 80 to 100 mm hg. Bio202h5s oxygen dissociation curves and bohr effect. The curve is usually best described by a sigmoid plot, using by a formula of the kind. Oxyhb dissociation curve to calculate blood oxygen content.
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