Circulatory System Flashcards
circulatory system
connects the fluid that surrounds cells with the organs and organ systems
open circulatory system
bathes the organs directly in hemolymph (equiv to blood)
arthropods, molluscs
closed circulatory system
confined to vessels and distinct from interstitial fluid
ex annelids, cephalapods, vertebrates
cardiovascular system
vertebrate circulatory system
includes heart and blood vessels
atria and ventricles
blood enters atria
exits ventricles
three types of blood vessels
arteries, veins, and capillaries
arteries
carry O2 blood away from heart to the capillaries
branch into arterioles
capillaries
small, sites of chemical exchange between blood and interstitial fluid
capillary beds
networks of capillaries
venules
collect non-o2 blood from capillaries
veins
venules converge into veins; return non-o2 from capillaries to heart
endothelium
the inner lining of blood vessels surrounding the central cavity
made up of flattened epithelial cells
capillary structure
have just an endothelium and basal lamina
arteries and veins
have smooth muscle around endothelium, and connective tissue around smooth muscle
veins have valves
to prevent backflow of blood due to pressure and gravity
arteries have thicker walls
to withstand the high pressure away from the heart
systolic pressure
pressure in the arteries during ventricular systole (contraction)
highest pressure in arteries
systolic pressure causes
contraction which causes a bulge; this is a pulse
diastolic pressure
pressure in the arteries when they are relaxed or when the ventricles are relaxed
