Chapter 50 Flashcards
What are the advantage of closed circulatory systems?
1) more rapid blood flow
2) closed systems can direct flow of blood to specific tissues by changing the diameter of the vessels under nervous control
3) blood cells and specializes carrier proteins can be retained with the circulatory system
What are open circulatory systems?
Muscular heart assisted in the distribution of blood
Fluid returns either through open pores in the heart (Ostia) or through open veins
How has the vertebrate heart evolved?
Fishes: only one atrium and one ventricle, blood oxygenated by direct passage through the gills
Adult amphibians: that used lungs for oxygenating the blood, heart has 3 chambers with two artia, ventricle is partially divided to keel the systematic and pulmonary systems mostly separate
Crocodilians: 4 chambered hearts with 2 artia and 2 ventricles and 2 aortas, during periods of submersion/inactivity, blood bypasses the lung and all the circulation is directed to the body
Birds/mammals: 4 chambered heart, the systemic and pulmonary systems are completely seperate
Why are separate pulmonary and circulation efficient?
Increases efficiency of oxygenation by lungs and delivery of blood to body
Path of blood flow
Oxygen rich: left ventricle-aorta-mitral valve
Oxygen poor: tricuspid valve-right ventricle-pulmonary valve
How is cardiac muscle connected?
Muscle fibers are electrically connected by gap junctions, forming a syncytium like that off smooth muscle
