CV I Flashcards
Outline the blood vessel names from heart back to heart
heart .. artery .. arteriole .. capillary .. venule .. vein .. heart
outline the layers of a blood vessel starting at the lumen
tunica intima (endothelial cells) .. internal elastic lamina .. tunica media .. external elastic lamina .. tunica adventitia
not all blood vessels have all these stxs
tunica intima is composed of two things for veins and three for arteries/arterioles. what are they
endothelium
loose CT
internal elastic membrane (artery)
tunica media is composed of circullary arranged smooth muscle cells, what is it’s function?
controls lumen diameter thus controlling blood pressure
_____ ______ are fenestrated sheets that can be interspersed in tunica media and
elastic laminae
what is tunica adventitia/externa composed of? (3)
loose CT
vaso vasorum in large vessels
fine autonomic nerves
arteries: what makes internal elastic membrane and what is it’s composition?
smooth muscle cells
perforated membranous elastin
how many layers of smooth muscle must there be for a vessel to be an artery
5
what type of connective tissue is in arteriole tunica media?
collagen III
elastic membranes
what are the two types of arteries?
elastic arteries
muscle arteries
what is the function of elastic arteries
protect smaller vessels and give continuous flow
what is abundant in elastic arteries?
elastic laminae in tunica media
what is the main function of smooth muscle in elastic arteries?
synthesize elastin
how is tunica media arranged in muscular arteries and does it have elastic membrane?
spirally
has an internal and an external elastic membrane
what is the function of muscular arteries
smooth muscle contraction regulates diameter and controls blood pressure and blood distribution
how many layers of smooth muscle are in arterioles
1-4
do arterioles have elastic membrane?
no external
sometimes internal
what is the function of arterioles?
control blood flow to capillary beds via smooth muscle precapillary sphincters
principle source of peripheral resistance
what happens at capillaries?
exchange of substances between blood and ECM
capillary structure?
one layer - tunica intima
endothelium and basement membrane
what are the three types of blood capillaries?
continuous
fenestrated
discontinuous
structure of continuous capillaries?
tight junctions between endothelial cells
where are continuous capillaries found?
blood/brain barrier
muscle (maintain electrolyte balance)
skin (pathogens)
structure of fenestrated capillaries
tight junctions but holes in basal and luminal plasmalemmas join
holes can have diaphragm
where are fenestrated capillaries found?
intestinal villi kidneys choroid plexus liver endocrine glands
discontinuous capillaries are called what in liver, spleen, and bone marrow?
sinusoids
structure of discontinuous capillaries
lack junctional complexes and basement membranes
often thicker and twisted to slow blood flow for Ag removal
big enough gaps for RBC to leave circulation
what is the function of lympathic capillaries?
return lymphocytes and protein to blood after filtering Ag at lymph nodes
structure of lymphatic capillaries?
similar to discontinuous blood capillaries
valves prevent backflow
organization of lymphatic capillaries?
intermingled with blood capillaries
combine to form large lymph vessel that drain into lymphatic duct and thoracic duct
that return fluid to blood
how do you distinguish between venule and capillary?
diameter of venule > 10 micrometers (RBC = 8)
structure of venules
single cell layer
how does structure of venule change as diameter increases
smooth muscle, fibroblasts begin to appear outside endothelium
structure of veins
three layers (tunica intima, media, adventitia) valves keep blood moving back to heart
do veins have internal elastic membrane?
NO
how many layers of smooth muscle in veins?
1-2
what helps propel blood flow in veins?
skeletal muscle contraction
what is arteriovenous anastomoses (AV shunt)
links arteries to veins or arterioles to venules
bypasses capillaries
what is the purpose of AV shunts
regulate surface temperature at soles, palms, fingertips, nose, lips, erectile tissue
when AV shunt is close, what is consequence
inc. heat loss, blood goes to capillary bed
when AV shunt is open, what is consequence
decrease heat loss, blood doesn’t go to capillary bed
compare and contrast size, structure of veins and arteries
lumen of vein larger than accompanying artery
internal elastic lamina in arterial vessels
tunica media thickest layer in arteries, tunica adventitia thickest layer in veins
only veins have valves
what are five mechanisms of transport across endothelial cells?
diffusion pinocytosis, transcytosis fenestrae paracellular pathway endothelial discontinuities
what compound increases leakiness of junctional complex?
histamine
what is angiogenesis
development of new blood vessel from existing vessel
what do new blood vessels emerge as and what are they made from?
capillaries from small venules or other capillaries
what are the five steps in angiogenesis
- endothelial cells enzymatically dissolve basal lamina
- cell migration toward growth factors, leading to edge ruffles, contact maintained w/ cells behind
- migration and alignment of endothelial cells to form solid sprout
- endothelial cells proliferate and sprout forms lumen
- cells make contact w/ another angiogenic sprout or existing vessel
what is collateral circulation?
more than one way to deliver blood to some part of the body
how is angiogenesis related to collateral circulation?
angiogenesis allows for collateral circulation
what are two main arterial diseases?
hypertension
atherosclerosis
what is the main contributor to hypertension?
peripheral resistance dictated by tunica media tone of arterioloes
how does atherosclerosis happen in general
endothelial damage leads to thickening of the tunica intima and obstruction of lumen
what three events lead to tunica intima thickening in atherosclerosis
- monocytes and LDL enter tunica intima
- smooth muscle may migrate to intima
- cytokines and growth factors stimulate smooth muscle and macrophage
proliferation
what three problems occur in athersclerosis?
- clot develops within plaque, rapid proliferation, obstruction
- necrotic plaqu embolizes causing obstruction at another site
- wall becomes weaker, forming aneurysm, then rupture
