Transport of Gases

TRANSPORT OF GASES Blood to specialized body fluid that delivens necessary substances to the body cells, such as matrients and respiratory gases. The respiratory gases are the oxygen and carbon dioxide A continuous supply of oxygen is requined by living cell. abgewe ence of oxygen in few minutes cases Unconsciousness and death. A normal male at nest used about 250 millilitres of oxygen pen minute, the requirement treneases many feld during vigorious excention. →All of this oxygen is transporited by the blood. The blood capillanies of the Mungs brings the blood fonto the alveoli where the pressure of oxygen in blood is relatively high. →About 19-20ml. of oxygen to carried by 100ml-of antenial blood and 14-15 ml. by 100ml of Venous blood. oxygen enters the venous blood in the lungs. 91 leaves the blood stream in the tissue-capillaries and goes to the tissue. "Treamsport of oxygen: As a result of breathing fresh air with more oxygen reaches the lungs and fills the alveoli. → oxygen in the alveoli diffuses into Blood The blood inside concentration of охудел Canbon dioxide. capillantes but highere has a low concentration oxygen frien alveolan air passes into the capillaries and cae from the capillanies panes Into the alvestan air simply by the process & diffusion. pulmonar Diffusion of gases occure Only ton dissolved condition →After neaching into the pulmonary capillanies the oxygen is transported to the different tissue. Tream port of oxygen takes place bay 2) As oxy haemoglobin Ⅱ) As dissolved state in plasma. 5) As oxy haemoglobin: About 98% of O2 is It occurs ansported through Follocaings this method. by following steps a) formation of oxy has oxy har möglibin b) Transport of oxygen into the tissue... aj formation of oxy haemoglobin: on mammals about 15-20 ml. of pen 100ml. of blood. oxygen ts cannied →2% of oxygen can dissolve in 100ml. of plasma at nonmal atmospheric pressure, the nest 98% combines with the respiratory pigment haemoglobin present in R.B.C Haemoglobin can combine with oxygen forming a loose chemical compound known as oxy haemoglobin The amount of Os in the haemoglobin will combine 16in is dependent upon the forming oxy harmorabin Hevision (pantial pressine) of oxygen in the medium whene haemoglobin is placed. of the Oz tension is high a lange amount of oxy haemoglobin will be formed cimeneas in a medium low tension the liberating oxy haemogla bin bin will breakdance insa →Haemoglobin chrismo protein having foun Subunita each of which contains haem attached with a polypeptide chain Moleculan weight of haemoglobin is 68,000 →st contains foun atorns of inon in fernous form- Each atom of Iποι of afont oxygen. combine with one milewe As the haemoglobin contains Hour haem unit ft reacts with foure molecules of formation of Hby Of with the → Reaction of Haemoglobin in toure separate burt Simultaneous reactions ane. Hby +02 Hby 02 Hby + 202 →Hby Oy Hby + 302 H'by O Hby + 402 →Hby 08 oxy haemoglobin discociation cunve: There is a definite propention oxy haemoglobin to haemoglobin present in the blood at any time The relation between pantial pressure of and amount of oxy haemoglobin formed or distort has been studied unden various conditions - The result when plotted So called to a graph it form oxy haemoglobin Nature of the curve: dissociation cuave a unve. The cunve shows a of haemoglobin with os Steep rise in pencentage Satunat At a pantial pressure of 70 mmtly a moleruje oxygen of approximately of haemoglobin becomes fully saturated and to completely convented finto oxy haemoglobin.. →Any increase in oxygen tension (partial pressure) does not The change the amount of oxy haemoglubín formed. first pant ant of the curve is nearly Vertical the last part of the curve is almost horizontal and the whole curive is sigmeid in shape. Paretial pressure of in mm Hg. Explanation of the sigmoid shape of the curive: Each molecule of globin consists of four polypeptide chains to each of which is attached a molecule of m of harm with Fe2+ one molecule of capable of combining with oxygen. As soon as one molecules of haem combines cwith Or the other three molecules in the same complex of the globin acquines polypeptide a great affinity for Os and reapidly combines with 44. → The rapid oxygenation of haemoglobin in the initial phase of is exposure to o₂ to known as allostenie activation and rapidly combines with it →The rapid oxygenation of haemoglobin in the Initial phase of its exposure to O₂ is known as allustenie activation and explains the shanp rixe in the dissociation cunve. Factors Enflu Enfluencing the shape of the cunve: 1) Bohri's effect: The affect of co₂ concentration on dissociation of oxy haemoglobin was discovered by christian Bohn and known as Bohr's effect. The increase in the concentration of co decreases the amount of oxygen that canbe cannied to the blood at a given pantial pressure foxygen, higherr concentration more of xy haemoglibin release of oxygen. of Co₂ Stimulates to dissociate and →on presence of high of peo₂ the canve ta Mo 60 100 Pantial Priess Of 2 2) Pll: Acidity in the blood shifts the dissociation Cunve to the night Duning exercise Lactic acid and other acids organic produced in the active tissue favours release of oxygen from oxy haemoglobin... 3) 2: increased Temperature: dissociation cunve to the temperaturce shifts the night →This also favours release of oxygen in the active tissue with therreased blood How and metabolic activity. 4) bi phosphoglycenic acid: phosphoglycenic acid to formed within the RiBe by glycolytic pathabay. → Diphosphoglycenic acid favours the dissociation oxy haermaglabin to haemoglobin and oxyge the dissociation runve to the b) Transporet of oxygen in the tissue: oxygen in combined state as oxy haemoglobin carried by blood to diffement organs and tissues. →The concentration of oxygen and cell is always is always highen. In the tissue fluid lower and co₂ concentration In the region of low oxygen concentration oxy haemoglobin breaks daon releasing oxygen which diffuses out from the blood capillaries to the issue fluid and from there to each and every cell. →The dissociation of oxy haemoglobin to also controlled by the concentration of CO2. COL dissolved in water to form carbonic acid (H₂l's) and Increases dissociation of acidity. Thus reesults in the oxyhaemoglobin. IC) As dissolved Blage in plasma: → only 2% of oxygen is transported. dissolved in the plasma and The free oxygen transported through the tissue the blood circulation to dissolve in free oxygen oxygen →Tissue Huid →Tissue. diffuses into Treans pont of carbon Dioxide The co, ts produced as a result of oxidation food stuffy. The coz then diffuses out of the cells tato the tissue fluid and then into the blood of capellanies The cox is transported through the blood by following three methods. A) As physical Solution As bicarbonates As carbamino compound. 4) Ay physical Bolution: About 5%-7% of co to carried in physical Solution of bloed. As soon as Co₂ enters the blood a part of if dissolves to plasma to form carbonic acid. →The canbonic and dissolves in plasma and is transponted as Simple solution- H₂log in a weakacid, it cames acidosis and to buffened wed by phosphates and proteins present in the blood, B) As bicarbonates: 97 has been maintioned that neady 85% of total coz produced in the body to cannied as bicarbonates in the blood, chiefly as potassium- bicareben a te In the plasma in the RBC and sadium bie As bicarbonates in the RiBe Th RBG contain an enzyme carbonic anhydrias Hence it increases the reaction between Co₂O H₂o forming carbonic acid. →The canbonic acid is immediately conézes to give rise bicarbonate and hydrogen tons. CO₂H₂O H₂CO₃ 3 (canbome acid? H++ H103 (Bicarbonate) H₂CO₃ combines imme Satte of immediately with the potassium Haemoglobin formed potassium bicanbin Potassium Haemoglobinate Potassium biconbonate Free Haem As bicarbonates in plasma: The plasma proteins moxtty Sodium Edenoted as Na Pre) and me main combined with Form bicarbonates. Na pr+H₂O HP + NaHCO3 chlorcide shift an Hamburgerr phenomenon: when the whole blood ih latunated with Cor the following changer ane Been 1. The bicarbonate contents of plasma and RBC 2. The chloride content of plasma is diminished 3. The total base (cations) of both ploumin R.Bic remain unchanged." "The watere content and the volume of Reave inencase concentration of Heos within the R.Be therefore very high becomes ver a level much within a Wighere shint time and attains. than that in the pla plasma. since the RBe cell membrane is impermeable to positively changed frons some theas from within the Ribe migrates into plasma and some ef from the plasma migrates within the Ree for exchange of ros The exchange of et and Heos tons between plasma and Rees is known as chloride shift phenomenon and was discovered by Hamburgen in 1927. Majore steps in chronida shift: The membrane of the RBC is not permeable to basic tous k+, Na+ iso, el etc. ete but is permeable to anions when cox enters the blood stream to the tissue capillaries H₂cos to formed. very little in plasma but langely to the Rise because RBC ane nich in carbonic anhydrase and protein routeur. The RBe contains 4-5 times mane protein than the plasma. H₂ toy reactions with KHE in the Rebe producing KHSOs and HHE. Thus the bicarbonate content of RBC increases and there by the reaction of the cells tends to become alkaline. To maintain a constant pH either the alkali ton (K) is to out of the cell an acid l get the plasma should enter the cell. ells • freee Heos ton now tends to make the coll sew reaction acid. This is prevented by the wigs we of Hegg ton from RBC into the plasma. combines with tree Nat of Nael which was left free by the shift of Natt eas in the plasma. chionine ton and お All the above captllaries changes takes place in the tissue These changes ane breefly represente Tissue Fluid coco Playma Ngel Nat Naheos In the lungs these changes ane reversed chlorine comes out of the fells reacts with Natt Tos plasma fe ferming Nael and carbonic acid. → carbonic acid thus liberated the lungs through passes out the In the tissue capillaries chloride shifts frrow the plasma into the cells There by the osmotic pressurce of the cell will the water will be dreawn in cand the cell volume will increase congon the palmonary capillaries it shifts from the cets buck to the plasma This will reduce the osmotic pressure of the cell and the cell volume wi'll shink () As carbamino compound: About 10% of cos forms loose canboming comprind with plasma pristeins in blood planma The preoteins of blood plasma dissociates into Aminoacids The aminoacids on oxidation produce two diffenent Yorups the amim group enth) and candentyl ganny (COOH) The aminogroup combines with cas and forms coxbamine compound These produce in 1% concentration in antenial blood and 1.5% in Venous blood. Nh₂ + Co₂ NHCOOH (carbamino compound) ⅱ) with Haemoglobin in RBCs: cos combines directly with fire aminogroup of the globin and forms canbamino compounds which may represented as follows. H6-Nth + 10 HENH COO + H+ This occurs is independent of carbonic anhydrase and therefore the neaction is not inhibited by eyanide. co to not faitially changed into haces within the since the concentration of hal hae moglo bin Riive to high a laregen fraction of curbamine to mprants auce cannied with in the RBC than in the plasma 12 Removal of cos from the nespiratory Surface to the external environment: →co2 in blood is always in combined state which forms bicarbonates, carbonic acids and loose canbanino compounds. → These compounds are eannied to the lungs, where these break down unden the influence of factores and liberated Co2. following is HaC0z canbonic anhydriase h+2 2 NaHCO3 Archidity of Na₂CO₃ + th° +6°2 Haemoglobin HENH COOH Reductions Hb Nth + 102 The cos liberated in this mannere diffuses out of the capillary walls into the allerlan air of lungs. The peas in tissue fluid to 46 mintly and in lungs alveoli to 40 minitly so coe diffuses frum tissue fluid into the antenial blood of tissue capillantes Clungs alveoli)