Gas Transport I (2023-2024) PDF

Block 1.3 (2023-2024) Gas Transport l Done by : Mousa Bu hulaiqah Jouri Alghanam What are the blood gases that important for our body ? a.W O2 &CO2 O2 : for cells to do metabolizm and physiological activity CO2 : it is waste for metabolic activities so body need to get r...

Block 1.3 (2023-2024) Gas Transport l Done by : Mousa Bu hulaiqah Jouri Alghanam What are the blood gases that important for our body ? a.W O2 &CO2 O2 : for cells to do metabolizm and physiological activity CO2 : it is waste for metabolic activities so body need to get rid of it or it’ll be toxic and cause harm to the cells. If the body didn’t remove the CO2 it might increase the acidity (PH go down) respiration is the best way to supply our body with O2 and remove the CO2 after metabolic activity The first step of respiration is “ventilation”( gas exchange 1 ). First gas exchange 1 :the air will enter the lungs by the mechanism of breathing. Gas exchange 2 : O2 and CO2 will exchange between alveoli and pulmonary capillaries After the Gas Exchange 2 the blood vessels will transport the gases to the tissues and there will occur the next step Gas exchange 3 : occurs between the blood vessels and the tissues how O2 transported in the blood ? 1-Hemoglobin one of major components of RBCs and it’s responsible for transport gases 2-Also O2 can dissolve in the plasma to be transported  There are two forms of O2 to be transported in blood : 1- the minority dissolved O2 is in the plasma 3% Dissolved form : 1-After gas 2- the majority is transported by exchange on the binding to hemoglobin 97% level of the lungs 2- This oxygen will bound to the hemoglobin found in pass through the the erythrocyte “RBC” will be alveoli into plasma reaching the tissue and gas so it’ll be dissolved exchange will occur on the level of and transported as tissue and the cells will take up this a dissolved form oxygen to form different physiological functions. Reversibly means that the O2 can either bind and release Deoxy-Hb when there Oxy-Hb when there is O2 isn’t O2 binding to the binding to the hemoglobin hemoglobin Also it’s called tense Also it’s called relaxed state of hemoglobin state of hemoglobin  hemoglobin composed of tetrameric protein. Composed of two Alpha and two Beta subunits It’s involved not only in transported O2 and CO2 it’s also transport CO The hemoglobin like the car it cannot carry more than the maximum seat, which is four binding site ( maximum capacity)  Carbon monoxide CO : a toxic gas that have high competitive binding to hemoglobin ( it can remove O2 and CO2 and take their place) and cause shortness of breath and It can induce it’s harm within few minutes some of the heater machines might cause this type of toxicity Its also called silent killer ( kill without warning) because its kill quickly and its colorless odorless and tasteless ‫االخي قال انه مو مهم‬ ‫ر‬ ‫رشح كل هذا بس يف‬ ‫النه مب موضوعنا‬ The 1st noticeable thing is it's not linear, it's segmoid shape. Benefit from this curve: it shows the relationship between partial pressure O2 "X-axis" and hemoglobin saturation "Y-axis"“ Don’t confuse between saturation and the partial pressure Why sigmoid? At some point it will reach the saturation level and it’ll not go beyond 100% because its the maximum level of saturation Also the sigmoid shape reflects the positive cooperativity or allosteric effect If it was linear: the level of saturation will increase Cooperativity : its when one O2 binds to whenever the partial pressure increases. hemoglobin it’ll help the next O2 to bind it’ll be easier if there is more O2 in the hemoglobin ( each O2 will enhance the next one until saturation )  After hemoglobin reaches the maximum amount of saturation 97- 99% it need to release its Oxygen so it will leave the lungs and go to the tissues to release it after the releasing the saturation will be 75% and return back to upload more oxygen If you measure your blood O2 you will find it 97-99%. Patient with covid doctor measure their blood continually to check if there any drop in oxygen saturation. If there is the patient will need oxygen therapy otherwise patient might have hypoxia, which will affect organs function P50: it’s the partial pressure required to saturate 50% of hemoglobin “important concept “ To know the partial pressure look at the curve at the point of 50% of saturation, and from this point look down to see the level of partial pressure in the same point, so we can see in this curve the partial pressure that ‫مو موجود يف الكتاب بس حطيته لكم‬ requires to saturate 50% of hemoglobin is 30 (‫عشان تفهمونه )كالم الدكتور‬  if we say the O2 saturation is 100% that means all the binding site is taken by O2 and if we say 95-97% its mean there are 95-97% of binding site are taken Remember its mL NOT L In normal individuals the concentration of Hemoglobin (HB) is 15g/dL or 15g/100mL You should know the formula Doctor didn’t mention which one we will use but he used the 15g/100 milliliters all the time Each 100ml of blood can carry 20% volume of Oxygen “If” the saturation of hemoglobin is 100%. So if it wasn’t 100% there will be different number. If you want to calculate it multiply 20 with the For example: percentage in the arteries the saturation is 97% it For example the saturation is 60 will be 19.4g/100mL 20 x 60% is 12 In the vains its 75% it’ll be 14.4g/100mL What is the effect on Anemia of the oxygen carrying capacity ? Anemia is having low hemoglobin concentration caused by : 1- Defect in the red blood cells 2- Problems with iron absorption 3-issues with vitamin B12,intrinsic factors polycythemia the opposite is it defined as an increase in the absolute red blood cell (RBC) the curve will have an upward shift  Systemic arterial blood, we’ve the partial pressure is approximately 95 mmHg this corresponds to 97% of oxygen saturation 19.4-14.4= 5ml The 5ml is the amount used (delivered to the tissue)  During the intense activity (exercise) you need more oxygen so the delivered amount These numbers are from the of oxygen curve below will increase During exercise the delivered amount of oxygen is 15ml by each 100ml of blood which is three times more compared to the resting state  what is happening during exercise ? 1- Increase in ventilation rates 2- Increased temperature 3- Increased metabolic activity 4- Increase in the heart rate 5-more lactic acid because the body uses Anaerobic respiration which increases the overall body acidity All of these factors lead to right shift So what does the right shift mean? 2,3-BPG, also known as 2,3- Increase in P50 (partial pressure diphosphoglycerate, promotes required to saturate 50% of Hb) & hemoglobin transition from a decrease in the affinity high-oxygen-affinity state to a low-oxygen-affinity state. This means that in the lungs this will enhance the oxygenation of the blood and it will induce the curve to go the left because we need more oxygen on the level of the lungs and this what we call the bohr effect  Don’t forget that the Hb is a protein and it’s affected by many factors including the acidity that affect the structure of the Hb and it is affinity  Allosteric effect: it’s the binding of one molecule of oxygen in the binding site of hemoglobin will enhance the second and the second will enhance the third molecule until reach the saturation The carbonic anhydrase is an enzyme that will enhance the reaction by 5000 times so we can get rid of the carbon Carbonic Acid is dioxide quickly dissociated into hydrogen & bicarbonate ions Hb regulate the acidity by capturing ( taking up ) the H+ ions in the blood  Chloride shift is to maintain the electrical charge between the blood plasma and RBC cytoplasm  In CO2 we don’t require huge difference between the arterial and venous because the diffusion capacity of the CO2 is much higher than the diffusion capacity of O2  Quiz 1- In response to increased level of blood CO2 2- If there is lack in the Carbonic and increased acidity of the blood, the blood Anhydrase enzyme what will be the oxygenation in the lung is increased due to effect on the Pco2 levels in the tissues ? which of the following effect? ? A- Haldane effect A- It will increase B-Buffer effect B- It will decrease C-Bohr effect C- It will stay unchanged 4- During intense exercise to ensure extra 3- The shift of the oxygen-hemoglobin curve amount of O2 to active exercising muscle to the right following a decreased level of fibers which one of the following changes in which one of the following factors ? the O2 Hemoglobin curve would occur ? A. 2,3BPG. A. Left shift B.CO2. B.Right shift C.pH. C. No change D. Temperature Answers: D. Upwardshift 3- C 4- B 2- A 1- C Good Luck !