Lecture 9 Notes on Circulatory Systems PDF

Lecture 9: 24 Jan Open vs. Closed Circulatory Systems Vessel Characteristics Reading: 714-721, 700-706 1 1  Fluid Circulation (convection) define “fluid” within animals what fluids are circula...

Lecture 9: 24 Jan Open vs. Closed Circulatory Systems Vessel Characteristics Reading: 714-721, 700-706 1 1  Fluid Circulation (convection) define “fluid” within animals what fluids are circulated? how? 2 2  Components of Circulatory System 1. pump(s) – generate pressure to move fluid through tubes – “cardio…” 2. tubes – “open” vs. “closed” – “…vascular” 3. internal fluid – can exchange substances with external env., but stays within animal – exceptions? 3 3  Classification of Circ. Systems closed – enclosed vessels separate fluid from tissues – fluid (called what?) stays within vessels (mostly) so what fluid directly bathes tissue cells? – exchange by diffusion/transport across vessels 4 4  Classification of Circ. Systems open – fluid leaves discrete vessels…(fluid called?) – circ. fluid also bathes tissue cells directly 5 5  sinuses: larger spaces where hemoplymph collected, transported lacunae: network of spaces 25.24 among cells allowing hemolymph to circulate 6 6  All Arthropods Have Open Systems …but they differ in complexity what’s an arthropod? examples? (see back cover) 7 7  All Arthropods Have Open Systems …but they differ in complexity e.g. insect: fairly simple – body movements facilitate circulation compare with decapod crustacean – extensive arteries, even “capillaries” box 25.4 8 8  Who Has What and Why? 9 9  open closed 10 10  Athleticism & Closed Systems? insects: simple, open system, but… …highest metabolic rate in animal kingdom how? 23.31 box 25.4 11 11  Closed System Vessels: Vertebrates 12 12  Blood Vessel Components endothelium: epithelial lining – exchange across/through/between in capillaries – regulation of blood clotting – regulation of blood pressure/flow: NO tunica media – smooth muscle and elastin – regulation of blood pressure/flow tunica externa – collagen 13 13  Arterial Components arteries near heart: thick tunica externa – elastic…expands at high pressure…”pressure reservoir” arteries distal from heart: thick tunica media – “musclular arteries” arteriole: little tunica externa, still tunica media – lower pressure, but higher resistance; why? – large control over blood flow 14 14  Venous Components much lower pressure; can fall to 0 why? thinner tunica media, thick-ish tunica externa stretchy – valves to prevent back flow 15 15  What happens to blood components that leave circulation? 16 16  What happens to blood components that leave circulation? 17 17  What happens to blood components that leave circulation? 18 18 19 19