BIOL 1361 1nd Edition Lecture 22Outline of Last Lecture I. ExcretionII. Metabolic WasteIII. Excretory ProcessesIV. Excretory SystemsV. Kidney AnatomyVI. Kidney FunctionOutline of Current LectureI. Purpose of Circulatory System: Minimize Diffusion DistanceII. Circulatory SystemIII. Open vs. ClosedIV. Vertebrate Circulatory SystemV. CellsVI. VesselsVII. Flow RateVIII. Fick’s LawIX. Flow CircuitsX. PumpCurrent LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.I. Purpose of Circulatory System: Minimize Diffusion Distancea. Diffusioni. Supplies all cells with O2 and nutrientsii. Carries away CO2 and metabolic wasteb. Body Shapei. Flattened, thin body1. All cells within diffusion distance of external environment2. This maximizes surface area: volume3. Ex. Cnidria, Platyhelminthes (don’t have circulatory systems)c. Gastrovascular Cavityi. Body is 2 cells thick: each cell is within diffusion distance of external environmentII. Circulatory Systema. All cells are within diffusion distance of a capillaryb. Open Circulatory Systemi. Don’t have capillaries, instead have something else, sinusii. Can have 1 or more heartsiii. Has vessels from heart to sinusiv. Sinuses are like a sac that surrounds organsv. Vessels from sinus to heartvi. Fluid = hemolymphvii. Ex. Crabc. Closed Circulatory Systemi. Ex. Earthwormii. Can have 1 or more heartsiii. Blood flows within vessels throughout the bodyiv. Blood is separate from interstitial fluid1. Fluid between cellsIII. Open vs. Closeda. Openi. Arthropods ( insects, spiders, crustaceans)ii. Some mollusksb. Closedi. Fast-moving mollusks (octopus, squid, cuttlefish)ii. Earthwormsiii. All vertebratesIV. Vertebrate Circulatory Systema. Fluid = bloodb. 55% plasmac. 45% cellV. Cellsa. Erythrocytes = red blood cellsb. Leukocytes = white blood cellsVI. Vesselsa. Arteriesi. 3 Layers:1. Outera. Connective tissue and elastin2. Middlea. Muscle and elastin3. Innera. Endothelial cellsii. Purpose: carry blood away from heartiii. Lumen is much smalleriv. Muscle is thickerb. Veinsi. 3 Layers:1. Outera. Connective tissue and elastin2. Middlea. Muscle and elastin3. Innera. Endothelial cellsii. Purpose: return blood to heartc. Capillariesi. One layer1. Endothelial cellsii. Purpose: distribute blood through tissuesVII. Flow Ratea. Flow rate depends on the cross-section of the pipei. Flow rate is faster through a small pipe (same volume)VIII. Fick’s Law a. Total area of capillaries is very largeb. Flow rate is slower in capillariesc. This slow flow allows time for diffusionIX. Flow Circuitsa. Single Circulationi. Blood comes from the heart, to the gills, to the body and back to the heartii. Low O2 by the heartiii. High O2 by the gillsiv. This only occurs in fishb. Double Circulationi. Occurs in the rest of the vertebratesii. Ex. Panda, humaniii. Advantage:1. Higher pressure enhances flow speed2. Shorter turn-over time allows more frequent exchange of nutrients, wastes, and gassesX. Pumpa. Vertebrate heart structureb. 3-chambered heart: frogi. 2 atria, 1 ventricleii. dO2 and O2 blood mix in ventricleiii. Blood flow to lungs can be closed offc. Reptiles: 3 or 4 chambered hearti. Turtles, lizards, snakes (squamates)1. 2 atria, 1 ventricle2. dO2 and O2 blood mix in ventricleii. Crocodilians1. 2 atria, 2 ventricles2. dO2 and O2 blood separate in ventricles3. Blood flow to lungs can be closed offd. Birds and Mammals: 4 chambered Hearti. 2 atria, 2 ventriclesii. dO2 and O2 blood separatediii. Blood flow to lungs never shut offiv. Warmblooded (endotherm)v. Metabolic rate is highervi. O2 demand is
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