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56 Cards in this Set

  • Front
  • Back
what is the term used to describe the large vessels of the body? The small vessels?
macrovasculature; microvasculature
is the velocity of flow faster or slower at the capillaries and post-capillary venules?
slower
where in the circulatory system is the cross-sectional area the greatest?
capillaries
are the lymphatics part of the macro- or microvasulature?
microvasculature
what are the 3 layers outward of the blood vessel lumen?
tunica intima, tunica media, tunica adventitia
which layer of the blood vessel is in touch with the lumen?
tunica intima
what is the composition of the tunica intima?
simple squamous epithelium (endothelium)
what defines the outer limit of the tunica intima?
internal elastic lamina
what is the name for the layer of the vessels which lies between the internal and external elastic lamina?
tunica media
what is the composition of the tunica media?
circularly arranged smooth muscle cells and fibroelastic connective tissue
what is the name for the outermost layer of the blood vessels?
tunica adventitia
what is the composition of the tunica adventitia?
mostly connective tissue and some smooth muscles in larger vessels
which represent the blood and nerve supply to the vessels themselves? In which layer of the vessel do these lie?
vaso vasorum and nervi vascularis; tunica adventitia
which vessels have better developed layers, arteries or veins?
arteries
what is the dominant layer of the arteries? The veins?
tunica media; tunica adventitia
what are the name for the arteries closest to the heart? Why are they called this?
elastic arteries; they have a significant component of elastic fibers in their media interspersed with the smooth muscle.
what is the role of the elastic fibers in the elastic arteries?
to allow the vessels to expand during systole and contract during diastole
what is the name for the arteries downstream of the elastic arteries?
muscular arteries
what characterizes the muscular arteries? How many layers of smooth muscle exist?
layers of circularly arranged smooth muscle cells, often with a prominent internal elastic lamina; 4-40 layers
what is the role of the muscular arteries?
they regulate blood flow to the organs
what is the first member of the microcirculation which follows downstream of the muscular arteries?
arterioles
how many layer of smooth muscle are present in arterioles?
1-3 layers
which arterial segment is the main component of the TPR?
arterioles
what is the name for the arteries downstream of arterioles?
metarterioles
which types of arteries can feed the capillary bed?
arterioles and metarterioles
what are the names of connections between arteries and veins that bypass capillaries? Which types of arteries feed these connections? What controls this process?
arteriovenous anastomoses; arterioles and metarterioles; precapillary sphincter mechanisms
what is the average diameter of a capillary?
9-12 microns
what is the composition of the capillaries?
attenuated endothelial cells
what is the name for the cells which are located along the external surface of the endothelium of capillaries in a sporadic fashion? What is their function?
pericytes; contractile and regenerative
what are the 3 types of capillaries that have been identified?
continuous, fenestrated, and discontinuous
which of the 3 types of capillaries is the most common? How is exchange achieved across their walls?
continuous; diffusion and pinocytosis
which is the 3 types of capillaries have small pores in their walls?
fenestrated
by which structure are pores in fenestrated capillaries normally closed?
pore diaphragm
in which tissues are fenestrated capillaries normally found?
kidney, small intestine, endocrine gland
which type of capillaries have the largest pores? Which particles can pass through these pores?
discontinuous capillaries; macromolecules and plasma proteins
what characterizes the basement membrane of discontinuous capillaries?
it is normally reduced or absent
discontinuous capillaries are normally found in which tissues?
liver, spleen, bone marrow
into which vessels do capillaries drain?
post-capillary venules
what is thought to be the location where the majority of the blood-tissue gaseous and nutrient exchange takes place?
post-capillary venules
in which type of blood vessel do most of the white blood cells leave the circulation to enter the tissues
post-capillary venules
are the endothelial cells quiescent or metabolically active
metabolically active
what are 4 roles of the endothelial cells in blood vessels?
synthesis and maintenance of the basement membrane, fine-tuning of blood coagulation mechanism, and local control of blood vessel constriction/dilation and vessel wall permeability
in which process do the endothelial cells play a significant role?
inflammatory process
the larger veins have what composition?
considerable elastic fibers and some smooth muscle arranged longitudinally
which type of valves exist in the veins which permit unidirectional movement of blood to the heart?
bicuspid
what are the 3 layers of the heart?
endocardium, myocardium, epicardium
do lymphatics possess valves? What chacterizes their basement membrane?
yes; incomplete
what kind of collagen is found in the connective tissue of the tunica adventitia?
type I
how many layers of smooth muscle are most often present in metarterioles?
1 layer
which capillaries are most permeable to molecular transport?
discontinuous
in fenestrated capillaries, are pores within endothelial cells or between these cells?
within
the tone of smooth muscle cells encircling which vessels detemines how much blood enters capillaries?
metarterioles
which vessel looks like a large capillary under the microscope?
post-capillary venules
what function of the veins does the longitudinal smooth muscle allow?
blood storage
what kind of cells are Purkinje fibers?
modified cardiac muscle cells
are lymphatics strong or weak vessels?
very weak