biology chapter 5 Flashcards
protozoans
movement of gases and nutrients is accomplished by simple diffusion within the cell
cnidarians
have body walls that are two cells thick. All cells are in direct contact with either the internal or external environments so there is no need for a specialized circulatory system
arthropods
have open circulatory sytems in which their blood-like fluid (interstitial fluid) is in direct contact with the body tissues. The fluid is circulated primarily by body movements. Fluid flows through a dorsal vessel and into spaces called sinuses where exchange occurs
annelids
use a closed circulatory system to deliver materials to cells that are not in direct contact with the external environment
aorta
which branches into a series of arteries
capillaries
converge into venules, and eventually into veins, leading deoxygenated blood back toward the heart
right side of heart
pumps deoxygenated blood into pulmonary circulation (toward the lungs)
left side of heart
pumps oxygenated blood into systemic circulation (throughout the body)
atria
two upper chambers. Thin walled
ventricles
two lower chambers. Are extremely muscular
left ventricle
more muscular than the right ventricle because it is responsible for generating the force that propels systemic circulation and because it pumps against a higher resistance
atrioventricular valves
located between the atria and ventricles on both sides of the heart, prevent backflow of blood into the atria
tricuspid valve
the valve on the right side of the heart that has three cusps
mitral valve
valve on the left side of the heart that has two cusps
semilunar valves
have three cusps and are located between the left ventricle and the aorta (the aortic valve) and between the right ventricle and the pulmonary artery (the pulmonic valve)
heartbeat
made up by the systole and diastole
systole
is the period during which the ventricles contract
diastole
is the period of cardiac muscle relaxation during which blood drains into all four chambers
cardiac output
is defined as the total volume of blood the left ventricle pumps out per minute. = heart rate x stroke volume
heart rate
number of heartbeats per minute
stroke volume
volume of blood pumped out of the left ventricle per contraction
sinoatrial (SA) node
a small mass of specialized tissue located in the wall of the right atrium. It spreads impulses through both atria, stimulating them to contract simultaneously
autonomic nervous system
modifies the rate of heart contraction
arteries
are thick walled, muscular, elastic vessels that transport oxygenated blood away from the heart– except for the pulmonary arteries, which transport deoxygenated blood from the heart to the lungs