3 2 2020 1 Case study lower respiratory tract concerns tracheal mucosa More of the Respiratory System a Mucosa i ii Lined with ciliated pseudostratified columnar epithelium Goblet cells secrete mucus b Cilia are extremely important to clear debris from tracheal tract c Smoking destroys cilia that can grow back once smoker has quit d Lack of cilia is what causes the smoker s cough because coughing is the only way to clear mucus from entering the lungs 2 Case study chronic obstructive pulmonary diseases a Air pollution cigarette smoke other particulates i ii Can directly damage cilia Also triggers inflammation 1 Bronchitis b Cilia cannot move so unable to transport mucus up to pharynx c Eventual continuous struggle to breathe leads to strain on heart d Stage 4 is inability to get oxygen to all tissues results in mortality 3 Pressure lower pressure a Gases gas molecules move from an area of higher pressure to an area of i ii i ii i Diffusion down concentration gradient Eventually reach equilibrium 1 Same pressure b Boyle s Law a relationship between pressure and volume of a gas Absolute pressure P of a gas is inversely proportional to the volume V it occupies 1 As volume decreases pressure increases 2 As volume increases pressure decreases Decreasing volume increases collisions and increases pressure c Four different pressures influence respiration Atmospheric pressure 1 Patm 2 Pressure exerted by the weight of air molecules in the 3 atmosphere Force per unit area exerted against a surface by the weight of the molecules above the surface a More molecules at lower altitudes due to gravity For standardization Patm at sea level is used 1 Patm at sea level 760 mmhg 1 atmosphere Intrapulmonary pressure Ppul 1 2 Pressure in alveoli 3 4 Equalizes Patm at expiration 760 760 0 Fluctuates Intrapleural pressure Transpulmonary pressure Pip 1 1 Ppul Pip ii iii iv v vi Respiratory pressures are always described relative to atmospheric pressure 1 Negative respiratory pressure is pressure that is less than Patm a If Ppul is 0 mmHg it is equal to Patm 760 760 2 Positive respiratory pressure is a pressure that is greater than Patm a If Ppul is 4 mmHg it is less than Patm 760 756 4 mmHg 3 Zero respiratory pressure is a pressure that is equal to Patm If Ppul is 1 mmHg it is higher than Patm 761 760 1 mmHg a d Is the air we breathe pure oxygen The air we breathe is a mixture of gases i ii Mostly nitrogen iii 21 oxygen e Dalton s law of partial pressures The total pressure exerted by a mixture of gases is equal to the sum of the pressures exerted by each gas 1 Partial pressure pressure exerted by each gas in a mixture 4 External respiration pulmonary gas exchange a Takes place in the lungs Between alveoli and capillaries b Deoxygenated blood dark red blood becomes oxygenated lighter red Oxygen diffuses into red blood cells Carbon dioxide diffuses into alveoli c Partial pressure gradients and gas solubilities Steep partial pressure gradient for O2 exists between blood and lungs 1 Venous blood PO2 40 mmHg 2 Alveolar PO2 104 100 mmHg Partial pressure gradient drives O2 into blood 1 Difference of 60 64 mmHg Equal amounts of CO2 and O2 exchanged even though partial pressure difference of CO2 is lower than O2 1 Due to increased solubility of CO2 d Partial pressure does not necessarily indicated concentration dissolved i O2 not very soluble in water Even thought partial pressure in air and water is the same 1 2 Concentration of O2 in the air is higher than concentration in water ii CO2 is more soluble 5 Transport of hemoglobin a Oxygen is not very soluble in water 1 Same partial pressure as O2 but it has a higher concentration 98 5 of O2 is loosely bound to the protein hemoglobin in RBCs 1 5 of O2 is dissolved in blood b Each hemoglobin molecule is composed of four polypeptide chains 2 alpha and 2 beta Each polypeptide chain is bound to an iron containing heme group c How many molecules of O2 can each hemoglobin molecule transport i i i ii i ii iii i ii i ii 6 Internal respiration hemoglobin oxygen transport a Binding of O2 to hemoglobin is reversible reaction 4 molecules of O2 Binding in lungs Loading 1 Release in tissues 1 Unloading b Hemoglobin bound O2 is called oxyhemoglobin c Hemoglobin not bound to O2 is called deoxyhemoglobin 7 Transport of CO2 a Because tissue cells use O2 and make CO2 PCO2 is higher in tissues 45 mmHg than in systemic arterial blood 40 mmHg 1 So CO2 flows into the blood PO2 is lower in tissues 40 mmHg than in systemic arterial blood 100 mmHg 1 O2 flows out of blood into tissues b 7 10 is dissolved into plasma c 20 of CO2 is bound to the globin part of hemoglobin Referred to as carbaminohemoglobin Does not bind to heme 1 Does not compete for binding sites with O2 70 is transported as bicarbonate ions HCO3 in plasma d e Carbonic anhydrase formation of HCO3 Occurs mainly in RBCs 1 Non enzymatic reaction can also occur in plasma slower CO2 combined with water to form carbonic acid H2CO3 which quickly dissociates into bicarbonate and H i i ii i ii i ii i ii