BIO271H1 Lecture Notes - Lecture 8: Chordate, Collagen, Heart
Document Summary
Lecture 8: circulatory systems part 1 overview; components; Components of circulatory systems: pump or propulsive structures. Must have a pump to develop the high pressure for ex. Types of pumps chambered hearts contractile chambers creates the high pressure. Closed and opened circulatory systems. Open: circulatory fluid directly contact tissues. Mixes with interstitial fluid. Hemolymph directs blood to specific areas of the body (control) Hemocoel: hemolymph cavity: no direct contact between circulatory fluid and tissues. Distinct from interstitial fluid (between tissues and blood: molecules must diffuse across vessel wall. Ultrafiltrate of blood plasma. Bulk flow in animals lacking circulatory systems. Not a true circulatory system fluid being circulated is exactly the same as the external fluid. But external fluid has all the oxygen and nutrients they need. Sponge: flagellated choanocytes move water through porocyte into body cavity hemolymph. Choanocytes produces current (almost unidirectional flow) Cnidarians: muscular contractions of the body wall pump water in and out of gastrovascular cavity.
