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L25 2009 Circulation & Gas exchange

L25 2009 Circulation & Gas exchange - Gills Lungs...

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Unformatted text preview: Gills Lungs Blood Artery Vein CIRCULATION GAS EXCHANGE Lecture 25 26 Oct, 2009 and # # $ %& ' ! "" () ! • • Nutrient procurement – concepts & terms alimentary tract ammonium autotroph Bacteroides brush border calcium carbon diazotroph ectomicorrhizae endomicorrhizae epiphyte Escherichia coli essential amino acid essential fatty acid filter feeder flavonoid fungal hyphae gut evolution heterotroph hydrogen hydroponic infection thread legume leghemoglobin macronutrients magnesium micronutrients mineral molybdenum mycelium mycorrhizae niacin nitrate nitrite nitrogen fixation nitrogenase nutrient deficiency oxygen pantothenic acid parasitic phosphorus potassium Rhizobium riboflavin root nodules root hair scurvy sulfur symbiont vitamin A vitamin B2 vitamin C vitamin D vitamin K !' '( $ & '& ' & + "& & $ !’ $ $’ . % / ! " # !! $ %& !$ & $ ! '() !% ' * & #& '! ' $ $& '$ ' !$& , # ! & * ! '+ ! ,"% ' !& & $"! ! #$ ) %& -! ! ! ! "$ –$ %& &$ %& #&"! $ %! %& $ # ! & %& %& "&0 • • Tuesday, October 27, 6:00pm . Uris Hall G01 Auditorium Sponsored by Society for Natural Resources Conservation • Zoo and Wildlife Society • Veterinarians Interested in Developing Areas • Kyoto Now! • Sustainability Hub • Funded in Part by the Student Activity Fee • Free and Open to the Cornell Community & the Public ! " "$’ %$ "# &&$ “ "% ' "… ( )” Transport in plants – concepts & terms active transport apoplast apoplastic route autoradiography bulk flow bundle sheath 14 Carbon companion cell cortex cotransporter evaporation guard cells H+ ATPase mesophyll cell osmosis passive transport PCMBS phloem loading plasmodesma polymer trap positive pressure proton pump raffinose secondary active transport sieve element sieve plate stachyose stele stoma sucrose source sucrose sink symplast symplastic route transpiration vascular bundle vascular cambium vascular cylinder vein xylem Pre-enrollment guidelines for 1st year Biology majors current system REQUIRED new system starts F ‘10 REQUIRED Evolution Genetics Biochemistry Intro lab Intro lab Evolution Genetics Biochemistry Intro lab X Intro lecture CHOOSE 2 Intro lecture Ecology Physiology Special offer for 1st year Bio majors Take either Physiology or Cell biology in S ‘10 It counts as Intro lecture and Intro lab Cell & Dev biology 6 courses 7 courses Clicker question Would you be inclined to skip Intro bio lecture and lab in the spring to take… A. Physiology B. Cell biology C. I would rather take the Introductory courses Monday, 26 Oct. 2009 Pre-enrollment advising Room 302AB APPEL DINING HALL 5:45 PM Meeting place: West Entrance to Appel Center at 5:45pm Size isn’t everything diffusion diffusion diffusion Diffusion time is slow out source membrane in sink Concentration (C) high slope is ∆C/∆x Distance (x) Time to for diffusion is proportional to x2 100 microns 1 second 1 mm (1000 microns) 100 seconds 1 cm (10,000) 3 hrs Where we’re going 1. Open circulatory systems 2. Comparative vertebrate circulatory systems 3. Blood pressure and flow 4. Gas exchange 5. Control of breathing Gastrovascular systems Cnidarians jellyfish, hydra Flatworms Planaria Cavity openings extend to all cells. Few cell layers. Almost all cells are on the outside. Diffusion suffices for distribution Arthropods have open circulatory systems Inefficient distribution of nutrients frequent flow reversal Heart Arthropods carry O2 directly to all tissues through tracheal tubes Slow circuit time – 8 min in roach Low pressure Anterior Lateral vessel vessels Hemolymph in sinuses surrounding organs Ostia High blood sugar Accessory hearts at appendages No O2 carrying pigment Tubular heart Open circulatory system + tracheal respiratory system works, but probably prevents arthropods from achieving large body size In vertebrates the closed circulatory & respiratory systems have coevolved as a united system single circulation Evolution of circulatory-respiratory systems in vertebrate classes 3 Lung/skin double circulation Reptiles (except birds) Circulation through the mammalian heart Pulmonary artery (to lungs) Aorta (to body) Pulmonary artery (to lungs) Cardiac Cycle (systemic circuit from body) Pulmonary veins (from lungs) 2 Right atrium Anterior vena cava Left atrium 4 (pulmonary circuit from lungs) Pulmonary veins (from lungs) Semilunar valve Atrioventricular valve Semilunar valve Atrioventricular valve Posterior vena cava Right ventricle 3 Left ventricle (pulmonary circuit to lungs) (systemic circuit to body) 1 Heart electrical signals progagate in a coordinated spatial manner from the SA node to the AV node to the ventricles 1 Pacemaker 2 Signals are 3 Signals pass 4 Signals spread Normal EKG recording generates wave of signals to contract. delayed at AV node. to heart apex. throughout ventricles. SA node (pacemaker) AV node Bundle branches Heart apex Purkinje fibers Abnormal – atrial flutter ECG Velocity, area, and pressure differ in various parts of the circulatory system Fluid exchange between capillaries and interstitial fluid depends on balance of hydrostatic and osmotic pressures tissue cells interstitial fluid 15 m Cross sectional hydrostatic pressure osmotic pressure (esp. proteins) Poor regulation of osmotic pressure leads to adverse health Blood is a complex tissue composed of cellular and non-cellular (humoral) elements hydrostatic Pressure Lack of protein in diet can lower osmotic pressure osmotic Movement through capillary bed Kwashiorkor: edema from hypoalbuminemia Red Blood Cells Erythrocytes (RBCs) Bi-concave disks (diameter: 7 Specialized to carry O2 lack nucleus (mammals), Golgi, mitochondria loaded with hemoglobin (2.5 x 108) Hemoglobin globular protein 4 subunits (2 x 2) Heme groups with Fe atom reversibly bind O2 m) Alternative Pigments Myoglobin one subunit, same shape as single unit in hemoglobin. But only 20 amino acids the same as hemoglobin (out of 140). present in vertebrate muscle cells Alternative Pigments Hemocyanin Present in mollucs and many arthropods (except insects) as a soluble protein in the hemolymph Uses Cu instead of Fe Amount of O2 bound depends upon oxygen partial pressure Dissociation curve for hemoglobin O2 unloaded during resting metabolism pH also affects dissociation curve (the BOHR shift) High pH (basic): curve shifts to left. Low pH (acid): curve shifts right. steep slope reveals cooperativity among 4 subunits O2 available to high demand tissues pH is much lower in tissues than lung. O2 bound less tightly CO2 + H 2O ⇔ H 2CO3 ⇔ H + + HCO3 − Bohr shift helps load and unload hemoglobin from tissue High altitude adaptations Animals living at high altitude (lower PO2) have hemoglobin with improved binding affinity Low PCO2 Adrenal hormone erythropoetin (EPO) stimulates bone marrow to produce more RBCs Brainstem circuits control breathing Pons sets the tempo Medulla circuit(s) establish rhythmic breathing pattern EPO Inhalation: contraction of diaphram, intercostal (rib) muscles. negative pressure Exhalation: relaxation of muscles Phrenic nerve . Chemical control of breathing Extreme gas concentrations control breathing by negative feedback Increase in breathing rate is mediated by High PCO2 , low pH receptors on surface of the medulla & major vessels very low PO2 receptors on carotid artery, aorta Next up osmoregulation ...
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