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 airVentilation means inhaling air into alveoli and exhaling out of themGas exchange between airblood tissuesCellular respiration means intake of oxygen by cells from blood and releasing carbon dioxide into blood
3 VENTILATIONActive inspiration by inspiration muscles,passive expiration by elasticity of rib cageIn intensive work also exhaling by muscles
4 Gas exchange between air and blood AlveoliDiameter appr. 0.3 mmMore than 300 milj. (→ m2)Most dense network of capillaries in bodyGases are transported through 0.3 mm thick membranesCapillary diameter appr. 8 mm, contain 100 ml of blood → a cup of coffee on a tennis field !
5 Exchange of gases air blood tissues Atmospheric air:(partial pressure =concentration-% x air pressure)Alveolar air:(air is saturated with water in respiratory tract)
6 Exchange of gases air blood tissues P = partial pressure- Gases always move from higher partial pressures to lower through alveolar and capillary walls- Blood stays only secs, enough time for exchange.
7 Transport of oxygen in body: 99% of blood oxygen in Hb and the rest dissolved in plasma and red cell fluids1 g of red cell Hb binds 1.34 ml oxygenOxygen saturation of arterial blood in systemic circulation is appr. 97 %.Venous blood appr. 75 % (at rest)Oxygen saturation depends on partial pressure of oxygen in plasma (oxyhemoglobin dissociation curve)
9 Transport of carbon dioxide in body: - Mostly bound in water (≤ 80%)CO2 + H2O H2CO3one part (≤ 20%) bound in Hb (different site from oxygen)small part dissolved (5%)
10 MB4 + O2 MbO2 (toimii molempiin suuntiin) Myoglobin:O2 storage in muscles and heartprotein with iron as Hbbinds one molecule of O2releases O2 only after PO2 decreases very low
11 RESPIRATORY REGULATION Respiratory center (in medulla) regulates ventilation so that partial pressures of O2 and CO2 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 factorsPowerful during exerciseBoth voluntary and autonomousHumoral regulation (information from chemoreceptors):PCO2, PO2 and hydrogen ions (H+)Most important regulatory mechanism at rest