40 Questions
What is the main structural difference between post-capillary venules and muscular venules?
Post-capillary venules have a single layer of endothelial cells, while muscular venules have smooth muscle fibers in the media.
Which of the following accurately describes the histological structure of capillaries?
Capillaries have a lumen diameter ranging from 8 to 10 mm and are formed by a single layer of squamous endothelial cells.
What is the role of pericytes in the circulatory system?
Pericytes provide structural support to capillaries and post-capillary venules.
How do post-capillary venules differ from arterioles in terms of structure?
Post-capillary venules have a single layer of endothelial cells, while arterioles have two layers of smooth muscle fibers.
Which layer of the vascular channels conducts blood from terminal arterioles to post-capillary venules?
Tunica intima
What type of capillary has endothelial cells joined together by occluding junctions?
Continuous capillaries
Where are fenestrated capillaries found?
Lung
What is the function of arterioles in the cardiovascular system?
Responsible for peripheral resistance
What is the function of continuous capillaries?
Provides well-regulated metabolic exchange
Which type of capillary is characterized by numerous fenestrations?
Fenestrated capillaries
Which histological feature characterizes arterioles compared to other blood vessels?
Thick wall relative to narrow lumen
What regulates the blood flow into capillary beds through the closure or opening of precapillary sphincters?
Local metabolite concentrations
What is the role of cytoskeleton in regulating blood flow through capillaries?
Related to the contractile process
In histological sections, what distinguishes the lumen of veins from that of arteries?
Collapsed lumen containing RBCs
How are veins classified based on their diameter and wall thickness?
Large veins, medium-sized veins, and venules
Which type of blood vessel is characterized by irregular vascular channels with large openings in endothelial cells and wide intercellular gaps?
Sinusoids
Which blood vessel structure has a relatively thick smooth muscle layer and is responsible for thermoregulation at the body surface?
Tunica Media
Which feature is unique to arteriovenous (A-V) shunts compared to ordinary precapillary sphincters?
Have direct routes between arterioles and venules
In which type of blood vessel would you find delicate reticular fibers supporting the endothelial cells?
Sinusoids
Which blood vessel structure has endothelial cells that rest on a discontinuous basal lamina and are separated by wide intercellular gaps?
Tunica Intima
Which layer of arterioles is characterized by a thin layer with no internal elastic lamina?
Tunica intima
What is the composition of the tunica adventitia in medium-sized veins?
Dense fibro-elastic connective tissue
What function do the valves in medium-sized veins serve?
Prevent backflow of venous blood towards the heart
What is the percentage of the wall thickness that the tunica media occupies in arterioles?
30%
Which type of blood vessel contains more vasa vasorum in the tunica adventitia, veins or arteries?
Veins
What is the main function of the elastic laminae in the wall of large arteries?
Provide elasticity for inflation during systole
In medium-sized muscular arteries, what is a prominent feature of the tunica intima?
Relatively thin layer
What is the composition of the tunica media in medium-sized muscular arteries?
Predominantly smooth muscle fibers with little elastic and collagen fibers
Which characteristic is true about the tunica adventitia of medium-sized muscular arteries?
Merges into the surrounding connective tissue
What plays a crucial role in providing nutrition to the adventitia and outer part of the media in large arterial walls?
Vasa vasorum
What is the main component of the tunica intima in arteries?
Endothelium
Which layer of the artery constitutes 70% of the wall thickness?
Tunica media
What provides mechanical strength to the wall and controls the luminal diameter of blood vessels?
Smooth muscle
Which layer of the artery contains vasa vasorum, small blood vessels providing nutrition to the vessel wall?
Tunica adventitia
In arteries, what separates the media from the adventitia in many cases?
Thin external elastic lamina
Which type of arteries include the aorta and its large branches?
Large elastic (conducting) arteries
What are small blood vessels called that provide nutrition to the vessel wall?
Vasa vasorum
Which layer of the blood vessel wall blends into the surrounding connective tissue?
Tunica adventitia
What is the main component of tunica media in arteries?
Smooth muscle cells
Which type of arteries have the general histological structure of a blood vessel?
Large elastic (conducting) arteries
Learn about the composition and functions of the different layers that make up the arterial wall, including the tunica intima, tunica media, and tunica adventitia.
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