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Form and Function 2 Today’s topics: • Life in Land vs. Water The circulatory system allows multicellular organisms to exchange heat, water, nutrients, with their environment. External environment CO2 O Food 2 Mouth Animal body Respiratory system Nutrients Cells Heart – Physical Constraints affect the design of animals • Circulatory and Respiratory Systems! Circulatory system – Gas exchange – Open and closed circulatory systems – Osmosis (again) Interstitial fluid Digestive system Excretory system • Energy budgets Anus Unabsorbed Metabolic waste products matter (feces) (nitrogenous waste) 7 April 2014 Fig. 42-28 Fig. 42-3 Alveolus PCO2 = 40 mm Hg PO2 = 100 mm Hg Heart PO2 = 40 PCO2 = 46 PO2 = 100 Heart PCO2 = 40 Blood Hemolymph Circulatory system PO2 = 40 Circulatory system PO2 = 100 PCO2 = 46 Pores Oxygen Single Loop Tubular heart PCO2 " 46 mm Hg Heart Gill circulation Ventral vessels Closed circulatory system Double Loop Superior vena cava Capillaries of head and forelimbs 7 Pulmonary artery Pulmonary artery Capillaries of right lung Aorta 9 3 Ventricle Capillaries of left lung 3 2 4 11 Atrium Vein Open circulatory system Auxiliary hearts Carbon dioxide Gill capillaries Artery Dorsal vessel (main heart) PCO2 = 40 Body tissue PO2 ! 40 mm Hg Small branch vessels In each organ Interstitial fluid Pulmonary vein Systemic circulation Right atrium 1 Pulmonary vein 5 Left atrium 10 Right ventricle Left ventricle Inferior vena cava Systemic capillaries Aorta 8 Capillaries of abdominal organs and hind limbs 1 Fig. 42-UN4 Diffusion always moves down a concentration gradient. Diffusion of gasses depends on their partial pressure. • Atmospheric pressure = 760 mm Hg at sea level. • Air is 21% O2 • Therefore the Partial Pressure of O2 = 0.21*760 = 160 mm Hg At top of Mt. Everest, atmospheric pressure is only 250. Therefore PO2 = ______ How does your body respond to low O2 concentration at high altitude? Respiration in Aquatic Species Use gills instead of lungs Fig. 42-22 In water Fluid flow through gill filament Oxygen-poor blood Anatomy of gills Oxygen-rich blood Gill arch Lamella Gill arch Gill filament organization Blood vessels Water flow • Solubility of O2 is only .003% – Fish have to process more water than air breathers to get the same O2 • Temperature Operculum Water flow between lamellae Blood flow through capillaries in lamella – Cold water can hold more dissolved gas. For fish, warm water is the same as high elevation for us. Countercurrent exchange PO (mm Hg) in water 2 150 120 90 60 30 Gill filaments Net diffusion of O2 from water to blood 140 110 80 50 20 PO (mm Hg) in blood 2 • Water surface area, turbulence, salinity, etc. – Shallow, fast moving bodies of water hold more oxygen 2 Fig. 42-22 Fluid flow through gill filament Oxygen-poor blood Anatomy of gills Gills use counter current flow, also! Oxygen-rich blood Gill arch Lamella Gill arch Same current Counter current Gill filament organization Blood vessels Water flow Operculum Water flow between lamellae Blood flow through capillaries in lamella Countercurrent exchange PO (mm Hg) in water 2 150 120 90 60 30 Gill filaments Net diffusion of O2 from water to blood 140 110 80 50 20 PO (mm Hg) in blood 2 Exchange surfaces and water balance Diffusion stops when concentrations are equal Diffusion continues along the whole length because it does not reach equilibrium Approx. Human Water Budget! Water intake water intake in form of fluids water intake in form of semi-solid and solid foods water from oxidation Total daily water intake We lose about a cup of water a day just by breathing (and we lose a similar amount through our skin) 1000-1500 ml 700 ml 300 ml 2000-2500 ml Water output water loss in urine water loss through skin water loss through lungs water loss in stools Total daily output 1000-1500 ml 500 ml 400 ml 100 ml 2000-2500 ml Source: http://www.iv-partner.com/index.cfm?BEFDDE916A254231BF46392979BA89EA Positive pressure Osmosis (again) Blood pressure causes fluid to leak out of capillaries Body tissue INTERSTITIAL FLUID ψ = ψS+ ψP Capillary Water potential = solute potential + pressure potential Net fluid movement out Net fluid movement in H 2O What will happen if the pressure stops? Direction of flow Osmosis brings (most) fluid back in 3 Fig. 43-7! Fig. 44-4b Interstitial fluid Uptake of water and some ions in food Osmotic water gain through gills and other parts of body surface Uptake of salt ions by gills Blood capillary Tissue cells Lymphatic vessels Lymphatic vessel We have a second circulatory system, the lymphatic system. Excretion of large amounts of water in dilute urine from kidneys Osmoregulation in a freshwater fish Gain of water and salt ions from food Excretion of salt ions from gills Osmotic water loss through gills and other parts of body surface Basal Metabolic Rate scales with Body size 103 Elephant BMR (L O2/hr) (Iog scale) Fig. 44-4a Horse 102 Human Sheep 10 Cat Dog 1 10–1 Rat Ground squirrel Shrew Mouse Harvest mouse 10–2 10–3 10–2 10 10–1 1 102 Body mass (kg) (log scale) 103 (a) Relationship of BMR to body size 8 Gain of water and salt ions from drinking seawater Excretion of salt ions and small amounts of water in scanty urine from kidneys BMR (L O2/hr) (per kg) 7 Shrew 6 5 4 3 Harvest mouse Mouse Sheep Rat Cat Human Elephant Dog Horse Ground squirrel 0 10–3 10–2 102 103 10–1 1 10 Body mass (kg) (log scale) 2 1 Osmoregulation in a saltwater fish (b) Relationship of BMR per kilogram of body mass to body size Figure 40.20 Energy Budgets 4