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Transport of gases in body Respiration (Breathing)

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Presentation on theme: "Transport of gases in body Respiration (Breathing)"— Presentation transcript:

1 Transport of gases in body Respiration (Breathing)

2 Respiration = transport of oxygen from air into cells and carbon dioxide from cells to air Ventilation means inhaling air into alveoli and exhaling out of themVentilation means inhaling air into alveoli and exhaling out of them Gas exchange between air blood tissuesGas exchange between air blood tissues Cellular respiration means intake of oxygen by cells from blood and releasing carbon dioxide into bloodCellular respiration means intake of oxygen by cells from blood and releasing carbon dioxide into blood

3 VENTILATION Active inspiration by inspiration muscles,passive expiration by elasticity of rib cage In intensive work also exhaling by muscles

4 Diameter appr. 0.3 mmDiameter appr. 0.3 mm More than 300 milj. ( m 2 )More than 300 milj. ( m 2 ) Most dense network of capillaries in bodyMost dense network of capillaries in body Gases are transported through 0.3 m thick membranesGases are transported through 0.3 m thick membranes Capillary diameter appr. 8 m, contain 100 ml of blood a cup of coffee on a tennis field !Capillary diameter appr. 8 m, contain 100 ml of blood a cup of coffee on a tennis field ! Alveoli Gas exchange between air and blood

5 Exchange of gases air blood tissues Atmospheric air: Alveolar air: (partial pressure = concentration-% x air pressure) (air is saturated with water in respiratory tract)

6 - Gases always move from higher partial pressures to lower through alveolar and capillary walls - Blood stays only secs, enough time for exchange. Exchange of gases air blood tissues P = partial pressure

7 Transport of oxygen in body: 99% of blood oxygen in Hb and the rest dissolved in plasma and red cell fluids99% of blood oxygen in Hb and the rest dissolved in plasma and red cell fluids 1 g of red cell Hb binds 1.34 ml oxygen1 g of red cell Hb binds 1.34 ml oxygen Oxygen saturation of arterial blood in systemic circulation is appr. 97 %.Oxygen saturation of arterial blood in systemic circulation is appr. 97 %. Venous blood appr. 75 % (at rest)Venous blood appr. 75 % (at rest) Oxygen saturation depends on partial pressure of oxygen in plasma (oxyhemoglobin dissociation curve)Oxygen saturation depends on partial pressure of oxygen in plasma (oxyhemoglobin dissociation curve)

8 HB 4 + 4O 2 Hb 4 O 8 (works both ways)

9 Transport of carbon dioxide in body: - Mostly bound in water ( 80%) CO 2 + H 2 O H 2 CO 3 - one part ( 20%) bound in Hb (different site from oxygen) - small part dissolved (5%)

10 MB 4 + O 2 MbO 2 (toimii molempiin suuntiin) Myoglobin: - O2 storage in muscles and heart - protein with iron as Hb - binds one molecule of O2 - releases O2 only after PO2 decreases very low

11 RESPIRATORY REGULATION Respiratory center (in medulla) regulates ventilation so that partial pressures of O 2 and CO 2 in alveoli and arterial/venous blood stay roughly unchangedRespiratory center (in medulla) regulates ventilation so that partial pressures of O 2 and CO 2 in alveoli and arterial/venous blood stay roughly unchanged

12 Neural regulation (information from receptors in muscles,joints and lungs): More important in ventilatory regulation than humoral factorsMore important in ventilatory regulation than humoral factors Powerful during exercisePowerful during exercise Both voluntary and autonomousBoth voluntary and autonomous Humoral regulation (information from chemoreceptors): PCO 2, PO 2 and hydrogen ions (H + )PCO 2, PO 2 and hydrogen ions (H + ) Most important regulatory mechanism at restMost important regulatory mechanism at rest

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