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Circulation and gas exchange

Circulation and gas exchange. Evolution. Open circulatory system Insects arthropods No difference between blood and interstitial fluid = hemolymph Gas exchange: rate of transfer proportional to surface area. Evolution. Fish: 1 atria 1 ventricle Heart to gills, gills to body

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Circulation and gas exchange

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  1. Circulation and gas exchange

  2. Evolution • Open circulatory system • Insects • arthropods • No difference between blood and interstitial fluid = hemolymph • Gas exchange: rate of transfer proportional to surface area.

  3. Evolution • Fish: 1 atria 1 ventricle • Heart to gills, gills to body • Water is dense with little O2 per volume • Gills: countercurrent exchange • Gas exchange (blood flows one way while outside water going in opposite direction) • Thermo regulation • kidney

  4. Insects: system of tracheal tubes, gas exchange throughout • Amphibians: 3 chambered heart • Reptiles: double circulation • Pulmonary circuit + systemic circulation • NO mixing of oxygenated and deox blood

  5. Our system • 4 chambered heart • Double circulation: • Right side: pulmonary • Left side: systemic

  6. Rate of diffusion proportional to surface area • Protists: occurs over entire surface (cnid. Flats) • Earthworms and amphibs: across moist skin • Gills: warmer, saltier less O2 • Insects: tracheal tubes: branch out to do exchange with all body parts. Open circ. System NOT involved in transport: O2 CO2

  7. Lungs • Reptiles • Birds • Mammals • Lungs not in contact with all cells of body • Gap bridged by circulatory system

  8. Pharynx: food and air, epiglottis • Larynx: vocal cords (air only) • Trachea: cartilage rings • Bronchi: 2. Right is more horizontal. More stuff • Bronchioles • Alveoli: air sacs and capillaries. 1 cell thick

  9. Breathing • Diaphragm: negative pressure • Tidal volume: air in and out with reg breath • Residual volume: air that remains in alveoli and tubes after you breath out. • Us: air travels down 1 way street. • Birds: better: are travels through… no dead ends

  10. Controls of breathing • Pons • Medulla • Sensors in aorta

  11. Lungs: only site of gas exchange: need circulatory system • Breath: negative pressure breathing • Partial pressure: gas diffuses from its own high partial press. To low (press. Just this 1 gas contributes to the press. Of air (a mix))

  12. O2 does NOT dissolve easily in blood • Need HEMOGLOBIN to hold the O2 • Bohr shift: increase affinity for heme to O2 when pH is elevated (by high CO2) • Myoglobin: protein that binds and stores O2 in muscles

  13. Blood • Blood: • Connective tissue with liquid matrix • plasma and 3 types cells • Leukocytes, erythrocytes, platelets • 5L • Kidney maintains plasma (90% water) • All blood cells from pluripotent cells in bone marrow

  14. homeostasis • If low O2 • kidneys: erythropoietin: increase production of erythrocytes

  15. Disease • Blood pressure: 2 factors: • Cardiac output and peripheral resistance • Atherosclerosis: • Plaques/ hardening of arteries (cholesterol, LDL) • Hypertension: over time, elasticity of vessels • Heart attack: MI, coronary arteries • Stroke: blocked vessel

  16. Control blood flow to capillaries: • Pre-capillary sphincter • Smooth muscle: constrict blood flow to that cap. • Lymphatic system: lymph drained out of circulating blood. Same • Lymph nodes: lots of WBC

  17. Pathway of blood • Right atria (deox blood) • Right ventricle • Pulmonary artery • Lungs : pulmonary circulation • Pulmonary vein • Left atria • Left ventricle • Aorta: systemic circulation

  18. Atria: thinner walls • Ventricles: stronger • Valves: heart sounds are the closing of valves • 2 AV (atria to ventricle) • 2 semilunar. From ventricle out of heart • Pulmonary artery and veins : ONLY Time and artery carries deox and a vein carries oxygenated blood

  19. heart • Gap junctions: form communication • SA NODE: local control of rate. Special tissue in right atria

  20. Arteries: higher pressure. From heart • Veins: pressure from move skeletal muscle.

  21. Vocabulary • Systole • Diastole • SA node

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