CV 2 anatomy Flashcards
the _____ _____ contains an endothelium made up of simple squamous cells, a basal lamina/basement membrane of thin connective tissue layer of collagen, and in some a vessels an internal elastic lamina.
tunica interna aka tunica intima
the ____ ____ contains varying layers of elastic connective tissue(external elastic lamina) and or smooth muscle fibers
tunica media
a loose connective tissue layer that surrounds all but the smallest vessels made of fibrous connective tissue
tunica adventitia (external coat)
What 4 principal components do vessels have ?
- endothelium
- elastic tissue
- smooth muscle
- fibrous tissue
the aorta and its primary branches would be considered what type of arteries ?
elastic arteries
What is the thickest layer of the elastic artery ?
tunica media
composed of 40-60 layers of concentric layers of elastic tissue fibers
what is the function of the elastic arteries?
- hydrostatic pressure damping
- conduct blood from the heart to the distributing arteries
the elastic arteries have a high____content and high _______.
the elastic arteries have a high elastin content and high compliance.
the elastic arteries function to pressure dampen due to the Windkessel effect. Explain
the elastic arteries distend during systole and recoil during diastole which reduces oscillations in blood pressure.
Recoil maintains blood flow during diastole
what type of vessel?
- because they contain elastic tissue these arteries convert much of the systolic blood pressure into wall tension(stretch)
- wall tension is partially released during diastole thus maintaining hydrostatic pressure
elastic arteries
5 examples of muscular arteries ?
- facial
- brachial
- radial
- femoral
- tibial arteries
which layer of the muscular arteries is not typical?
The tunica media
- mostly smooth muscle: 10-40 layers of smooth muscle
- less elastic tissue fibers
what vessel?
lots of smooth muscle in the tunica media and comparatively small lumen compared to wall thickness
muscular arteries
what are the functions of muscular arteries?
- distributes blood to regions of individual organs
- gradually drops blood pressure by about 20 mm hg over the length of these vessels MOA: alters vessel radius in response to stimulus which alters vascular resistance modifying blood flow and or arterial blood pressure. BP also decreases along these vessels as described by P’s law
The structural progression of vessels from elastic to muscular is gradual and leads to arteries of mixed type. List 5
- axillary
- internal and external jugular
- internal and external iliac arteries
_______consist of small vessels that connect the arterial and venous circulations.
microvessels
the structure of these of these micro vessels consists of;
- proportionately thicker wall and smaller lumen than an artery
- elastic components are still present but no internal/external elastic laminae
- tunica media 1-5 layers of smooth muscle
arterioles
4 types of microvessels
- arterioles
- capillaries
- venules
- arteriovenous anastomoses
______ are the main controllers of peripheral vascular resistance and the greatest pressure drop
arterioles
what vessel
the resistance vessels: blood pressure drops by about 60 mm hg over the length of these vessels
arterioles
what vessel?
vasoconstriction and vasodilation: respond to nervous stimulation, hormonal stimulation, or local metabolite concentrations to adjust resistance and regulate blood flow or pressure
arterioles
the elastic laminae is no longer present in these vessels but still contain elastin
arterioles
these vessels are often co-located with venules
arterioles
which vessel has a lot of smooth muscle and can completely occlude (flow)
terminal (arteriole)
the structure of this vessel is endothelium and basal lamina only.( just a tunica intima)
No tunica media or tunica adventitia
capillaries
this type of capillary has a continuous endothelium without fenestrations
continuous capillary
where would continuous capillaries be located?
4
muscle and connective tissues, CNS(BBB), gonads
often covered by a diaphragm of radially oriented fibrils that allow numerous particles to pass through. large particles can pass through but fentrastions still to small for proteins and RBCs to pass
fenestrated capillaries
fenestrated capillaries are located where?
5
fenestrated capillaries are located where?
GI mucosa, endocrine glands, exocrine glands, renal glomerular capillaries, choroid plexus
sinusoidal capillaries are located where?
5
liver, bone marrow, spleen, lymph nodes, some endocrine glands
this type of capillary functions to permit relatively free exchange of fluid and small solutes between plasma and tissue fluids
fenestrated capillaries
Continuous capillaries and fenestrated capillaries contain a continuous basement membrane, but __________.
(What is different about sinusoidal capillaries)
sinusoidal capillaries have a discontinuous basement membrane
these capillaries contain very large openings in the endothelium that permit relatively free exchange of proteins and cells between tissue and plasma
sinusoidal capillaries
are capillaries always open? explain
Approximately 25% of capillaries are perfused at any time, most are not open, there is not enough blood to perfuse them
explain vasomotion in relation to capillary blood flow.
- precapillary sphincters and metarterioles contract and relax causing intermittent blood flow through capillaries.
what cause vasomotion?
release of chemicals from the endothelium (NO and endothelin)
what cause vasomotion?
release of chemicals from the endothelium (NO and endothelin)
________ are smooth muscle cells that surround the mouth of a capillary at the point where it branches from an arteriole.
precapillary sphincters
_____are the last chance for control over capillary flow, no smooth muscle in capillaries beyond this point
precapillary sphincters
precapillary sphincters are not _____ and controlled by ____ ____ concentrations.
precapillary sphincters are not innervated and controlled by local metabolite concentrations.
distributing (medium)/muscular arteries have a _____ _____ _____and a _____ _____ _______.
on the slides
internal elastic lamina and external elastic lamina
