Vessel Overview Histology Flashcards
Two components of the vascular system?
1) cardiovascular system - transports blood (includes the heart, arteries, capillaries, and veins)
2) lymphatic system - which returns tissue fluid (lymph) from the tissues back to the cardiovascular system
Vessels are three basic components….
1) tunica intima
2) tunica media
3) tunica externa
Tunica intima
- made of what? other name?
- underlying?
a simple squamous epithelium called the endothelium, with underlying loose connective tissue
Tunica media
-made of? (2)
thicker layer with smooth muscle and elastic fibers
Tunica externa
- made of?
- other name?
dense connective tissue
adventitia
cross section of a blood vessel
- blood is inside
- tunica media has smooth muscle cells that are circularly arranged (perpendicular to long axis of vessel)
- thin portion inside is the tunica intima
see higher powered image of cross section of blood vessel with three layers!
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the border between the intima and the media is wavy
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video of vessel layers
just read notes
Artery!
Tunica media is most evident! – wraps circularly
Smooth muscle – nuclei long – lots of nuclei – nice eosinophila
Deep to intima – loose connective tissue – elastic layer in between with media
Adventitia – blends in with surrounding CT
Tunica media of vein has lots more CT and fewer smooth muscle cells
What is the major histological difference between arteries and veins?
thickness and muscularity of the tunica media
arteries have a thicker, more muscular tunica media
capillaries are composed of what?
endothelial cells without a tunica media or adventitia
lymphatic vessels have a less developed what?
smallest lymphatic vessels have what?
tunica media
smallest lymphatic vessels have valves!
hitologically, differentiating between arteries/arterioles and veins/venules is best done by comparing…
vessels of approximately the same size!
arteries have thicker smooth muscle layer so their wall is relatively thicker compared to the size of the vessel itself with a narrower lumen!
shape of arteries/veins… diff?
arteries tend to be rounder
arteries/veins can have blood cells in their lumen but they can be washed away in the prep.
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all blood vessels are lined with what?
simple squamous epithelium - ENDOTHELIUM.
have flattened nuclei
the fatter nuclei in the wall of the vessel (particularly in arteries) belong to smooth muscle cells
Capillaries are difficult to find and identify because consist mostly of endothelial cells and are thin walled
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capillaries are apprx the size of what?
RBCs
lymphatic vessels compared to veins…
thinner walls than veins
lymphatic vessels will be devoid of….
RBCs!
what will lymphatic vessels be filled with?
“colloid” from precipitated lymph fluid as well as WBCs
veins also have valves but not in the smallest veins in the wall of an organ that we will see
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pink colloid in lymph vessels are cellular!
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in lymph vessels, will see a grater proportion of WBCs compared to arteries/veins
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video of lung hilus notes
Vein has wider diameter lumen!
Valves are covered by SSE – wihtin organ and has valve – is lymphatic vessel
study pictures on slides!! esp quiz
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