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Respiration system 3 (Respiratory disorders (Oxygen imbalances: Hypoxemic…
Respiration system 3
Respiratory disorders
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Excessive oxygen: nervous tissue damage, destruction of enzymes and death
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Chronic obstructive pulmonary diseases: any disorder where there is a long - term obstruction of airflow and reduced pulmonary ventilation (asthma causing bronchoconstriction)/ Smoking (inflammation of the bronchi and immobilization of cilia) and emphysema (alveolar walls break down and exhibit larger but fewer alveoli - less respiratory membrane available for gas exchange)
Infection disease: common cold, pneumonia (lower respiratory infection by bacteria) and tuberculosis (bacterium mycobacterium tuberculosis)
Gas Exchange
Alveolar Gas exchange: the process of oxygen loading and carbon dioxide unloading in the lungs. The efficiency of the process depends on the length of stay of an erythrocyte in an alveolar capillary and the length of time it takes for O2 and CO2 to reach equilibrium in the capillary blood
Factors affecting efficiency of alveolar gas exchange: concentration gradients of gases, solubility of gases, membrane thickness, membrane area and ventilation-perfusion coupling
Ventilation - perfusion coupling: ability to match/ adjust ventilation and perfusion to each other, depending on where the lung damage is
Reactions that occur in the lungs are the reverse of systemic gas exchange. As haemoglobin loads oxygen, hydrogen ions decline (as they dissociate from the haemoglobin and bind with bicarbonate ions diffusing from the plasma into RBCs). Chloride ions diffuse back out of the RBC (reverse chloride shift). The reaction of hydrogen ions and bicarbonate ions reverse the hydration reaction and generates free CO2 - diffusing into the alveolus and is exhaled
Gas Transport
Oxygen transport: Hemoglobin is four protein (globin) chains, each with one heme group. One hemoglobin molecule can carry up to 4O2. If only one oxygen is carried on the hemoglobin - it is still referred to as oxyhemoglobin (HbO2)
CO2 Transport: as carbonic acid in the plasma, as carbaminohemoglobin and the remainder is dissolved in the blood as a gas
Systemic Gas Exchange
CO2 loading: Due to metabolic activity, the partial pressure of CO2 is relatively high in the tissues. So CO2 diffuses into the blood and carried in the three forms noted.
Chloride shift: bicarbonate diffuses out of RBC in exchange for chloride ions diffusing in. Most of the H(+) bind to hemoglobin or oxyhemoglobin, buffering the intracellular pH
rate of CO2 loading adjusted to varying needs of tissues. Low level of oxyhemoglobin (HbO2) enables blood to transport more CO2. A high metabolic rate keeps oxyhemoglobin levels relativelly low and allows more CO2 to be transported
Oxygen unloading: when oxyhemoglobin unloads oxygen - it's called deoxyhemoglobin. When oxyhemoglobin in blood reaches an area in the tissues with a much lower partial pressure of oxygen (metabolically active tissues), the oxyhemoglobin unloads oxygen and diffuses into tissues
Factors that affect rate of O2 unloading: ambient partial pressure of O2, temperature, Bohr effect and DPG
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