BIO 203 Lecture Notes - Lecture 13: Electrocardiography, Sinus Venosus, Membrane Potential

27 views3 pages

Document Summary

The cardiovascular system and its physiology are significant in several regards. Evolution: multicellularity and tissue specialization, coupled with increased size, require bulk transport of important materials. Organism: distribution of respiratory gases, nutrients, chemical messengers, etc. , in a dynamic and adaptive manner to meet physiological needs. Health and disease: breakdown of homeostatic mechanisms can jeopardize life; adaptive responses to challenges can promotes survival; clinical applications. Components: propulsive organs (hearts; chambered, tubular, ampullar, pulsating vessels, pressure reservoir and distributors (arteries, transfer systems (capillaries, blood reservoir and return system (veins) Fluid leaves the vessels to filter through the tissues before returning to the heart. Fluid returns directly to heart through openings called ostia. Ostia have valves that allow hemolymph to enter the relaxed heart but prevent it from flowing in reverse direction. System of vessels keeps circulating blood from fluid. Pumped by one or more muscular hearts. Fluid flows more rapidly through vessels and can transport nutrients and wastes quicker.