Vascular biology Flashcards
What are the three layers of blood vessels?
Tunica intima Tunica media Tunica adventitia (externa)
What are the components of the tunica intima?
- Endothelium
- basal lamina
- Loose CT
- internal elastic lamina
What is the main component of the internal elastic lamina?
elastin
What type of endothelium comprises the tunica intima?
Simple squamous
What is the purpose for the fenestrations of the tunica intima?
Allows gas exchange
What are the 5 components of the tunica media?
1.concentric layer of 2.smooth muscle cells
elastin/elastic fibers
3.reticular fibers
4. proteoglycans
5. external elastic lamina, made of elastin
What are the components of the tunica adventitia?
CT layer
Type I collagen
elastic fibers
fibroblasts
What is the vasa vesorum? Where is it needed
“vessels of the vessels”.
Needed for vessels greater than 1 mm in diameter
Which have move vasa vesorum, veins or arteries?
Veins
What is endarerities/periarteritis?When is it seen?
Infection/inflammation of the vasa vesorum
Classic example is in syphilis
What is the network of nerves that supply blood vessels called?
nervi vasorum or vascularis
Where are nerves endings found in arteries?
in the adventitia, usually not penetrating the media
Where are nerves endings found in veins?
in adventitia and in the media
Are nerve endings more dense in arteries or in veins?
More dense in arteries
What type of neurons are found in the nervi vascularis?
Mainlu sympathetic
What do nervi vasorum nerves releasing (what is the neurotransmitter)?
Norepi
How do cells that connect to the nervi vasorum communicate the nervous signal to neighboring cells?
Through gap junctions
How are the endothelial cells of vessels oriented?
Long axis in the direction of blood flow
What is the shape of endothelial vessel cells?
flat and elongated
What is the specialization that can be found on the endothelial cells?
Microvilli
What are the junctions that exists between endothelial cells?
Junctional complexes
Myoendothelial junctions
What is the main transport process seen in the endothlial cells of the vascular system?
Pinocytosis
What is the result of shearing stress on endothelial cells?
Hyperpolarization of the cell, leading to hyperpolarization of smooth muscle above (through myoendothelial junction), and subsequent muscle relaxation
What are Weibel – Palade bodies?
Granules present in endothelial cells that contain:
- Factor VIII
- tissue plasminogen activator
- interleuking 8
- P-selectin
- others
What is the function of the P-selectin molecules found in the Weibel – Palade bodies?
Help leukocytes attach and migrate through endothelial cells
What are the five main functions of endothelial cells?
- Promote/inhibit coagulation
- modulate smooth muscle activity
- Regulate inflammatory cell traffic
- Transport
- Regulate angiogenesis
What is the function of prostacyclin in endothelia cells? Nitric oxide?
Vasodilators
Prostacyclin also has anticoagulation effects
What is the function of endothelin in endothelia cells?
Vasoconstriction
What are the major components of vessels that are increased in large arteries like the aorta? What doesn’t change?
Most smooth muscle, elastic fibers are increased
Endotheliim and basal lamina do not change
What components changes in the small arteries as compared to the large ones?
Less smooth muscle, elastic fibers, more CT
What are the components of the capillaries?
Only have the basal lamina and endothelium
What is the major component of veins?
CT
How much does the muscular component vary from large arteries to small? Veins?
Large change in arteries
Small change in veins
Looking at a slide of a vessel, you see a prominent elastic lamina. What type of vessel are you looking at (vein or artery)?
Artery
How does the tunica media in veins compare to that found in arteries?
Much smaller in veins
How does the tunica adventitia in veins compare to that found in arteries?
Much larger in veins
What happens to the elastic lamellae as we age?
Increases, but also there is fibrosis
What is the characteristic feature of the tunica media found in arteries?
large amount of alternating elastic lamella and smooth muscle
True or false: there are fibroblasts in the tunica adventitia and in the elastic lamellae?
False–only in the tunica adventitia
The first squiggly dark line in the elastic lamella in arteries is what?
The basal lamina
What connects the multiple elastic lamelle?
Elastic fibers
What components of the elastic lamelle is dysfunctional in Marfan’s syndrome?
The GAGs of the elastic fibers that connect elastic lamellae
What happens to the tunica intima of arteries as we age?
Increases d/t fibrotic changes
“lakes” of GAGs in the elastic lamellae of arteries is characteristic of what disease?
Marfan’s
What changes occur in muscular arteries as compared to normal?
Increased smooth muscle in tunica media, at expense of elastic lamellae (change to two)
What is the main resistance structure in the blood system?
arterioles
How many smooth muscle layers are present in arterioles?
1-2
What is the way described in lecture to determine an arteriole from a artery?
Wall-to-lumen ratio is 1
True or false: arterioles have a small tunica adventitia surrounding them
True
How does the lumen of a veinuole compare to that of a arteriole?
Veinuloe is much larger
What is the microcirculation?
The area between the arterioles and the veinuoles
What is a metarteriole?
A small branch of the arteriole that controls the circulation into the microcirculation via smooth muscle
What are pericytes?
Mesenchymal cells that surround capillaries and can differentiate into smooth muscle cells.
They are contractile
True or false: capillaries have a tunica adventitia?
False
What are the layers that capillaries have?
Endothelium
Basal lamina
What are the three types of capillaries?
Continuous
Fenestrated
Sinusoidal
Where are continuous capillaries found?
CNS, muscle, lungs
Where are fenestrated capillaries found?
kidney, intestines, endocrine glands
Where are sinusoidal capillaries found?
spleen, liver, bone marrow
