Circulation Flashcards
general characteristics of circulatory systems
1+ pumps/structures that apply force to drive fluid flow
system of tubes that the fluid can flow through
fluid that circulates through the system
bulk flow
aggregated movement of molecules together
allows fluids to move through an organism’s body faster than diffusion
what controls bulk flow of blood?
tubes, pumps, and valves
open circulatory system
heart type structure which is attached to tube-like structures whose ends are open to the rest of the organism
doesn’t allow huge control over the distribution of velocity of the system
closed circulatory system
heart and tubes are connected
supports relatively high pressures
evolved multiple times in animals
what does the high pressure in closed circulatory systems allow?
rapid adjustments in oxygen and nutrient delivery to specific issues
ultrafiltration of blood
artery
carries blood from the heart to capillary beds
vein
carries blood from capillary beds back to the heart
what is tunica externa made of?
collagen
what is tunica media made of?
smooth muscle and elastin
what is endothelium made from?
epithelial cells
elastic artery
has very thick tunica external
also has tunica media,, tunica intimate, and endothelium
muscular artery
has thinner tunica external, and thicker tunica media
also has tunica intima and endothelium
arteriole
has only tunica media surrounding endothelium
structures allows for its key role in blood distributions
leads into capillaries
capillary
specialized for transport of materials across the capillary bed
types: continuous, fenestrated, sinusoidal
continuous capillary
most common capillary type
present in the brain, muscles, and skin
fenestrated capillary
pores aid in movement of materials through the capillary beds
present in specialized organs (ex. kidneys, endocrine glands)
sinusoidal capillary
rare
has large intercellular lets, which allow protein movement
only found in the liver and in bone marrow
venule
only contains tunica externa and endothelium (NO MUSCLE)
vein
has tunica externa, a small tunica media, tunica intima, and endothelium