Anatomy of Arterial Wall Layers

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What is the main structural difference between post-capillary venules and muscular venules?

Post-capillary venules have a thick adventitia, while muscular venules have a thin adventitia.

Muscular venules contain pericytes while post-capillary venules do not.

Post-capillary venules are larger in diameter compared to muscular venules.

Post-capillary venules have a single layer of endothelial cells, while muscular venules have smooth muscle fibers in the media. (correct)

Which of the following accurately describes the histological structure of capillaries?

Capillaries have two layers of smooth muscle fibers in the media and a thick basal lamina.

Capillaries are surrounded by pericytes that form the endothelial layer.

Capillaries have a lumen diameter ranging from 8 to 10 mm and are formed by a single layer of squamous endothelial cells. (correct)

Capillaries have a thick adventitia and are connected to muscular venules.

What is the role of pericytes in the circulatory system?

Pericytes are responsible for oxygen exchange in the capillaries.

Pericytes help regulate blood flow by contracting or relaxing the precapillary sphincters.

Pericytes provide structural support to capillaries and post-capillary venules. (correct)

Pericytes produce red blood cells in the bone marrow.

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. Signup and view all the answers

Which layer of the vascular channels conducts blood from terminal arterioles to post-capillary venules?

Tunica intima Signup and view all the answers

What type of capillary has endothelial cells joined together by occluding junctions?

Continuous capillaries Signup and view all the answers

Where are fenestrated capillaries found?

Lung Signup and view all the answers

What is the function of arterioles in the cardiovascular system?

Responsible for peripheral resistance Signup and view all the answers

What is the function of continuous capillaries?

Provides well-regulated metabolic exchange Signup and view all the answers

Which type of capillary is characterized by numerous fenestrations?

Fenestrated capillaries Signup and view all the answers

Which histological feature characterizes arterioles compared to other blood vessels?

Thick wall relative to narrow lumen Signup and view all the answers

What regulates the blood flow into capillary beds through the closure or opening of precapillary sphincters?

Local metabolite concentrations Signup and view all the answers

What is the role of cytoskeleton in regulating blood flow through capillaries?

Related to the contractile process Signup and view all the answers

In histological sections, what distinguishes the lumen of veins from that of arteries?

Collapsed lumen containing RBCs Signup and view all the answers

How are veins classified based on their diameter and wall thickness?

Large veins, medium-sized veins, and venules Signup and view all the answers

Which type of blood vessel is characterized by irregular vascular channels with large openings in endothelial cells and wide intercellular gaps?

Sinusoids Signup and view all the answers

Which blood vessel structure has a relatively thick smooth muscle layer and is responsible for thermoregulation at the body surface?

Tunica Media Signup and view all the answers

Which feature is unique to arteriovenous (A-V) shunts compared to ordinary precapillary sphincters?

Have direct routes between arterioles and venules Signup and view all the answers

In which type of blood vessel would you find delicate reticular fibers supporting the endothelial cells?

Sinusoids Signup and view all the answers

Which blood vessel structure has endothelial cells that rest on a discontinuous basal lamina and are separated by wide intercellular gaps?

Tunica Intima Signup and view all the answers

Which layer of arterioles is characterized by a thin layer with no internal elastic lamina?

Tunica intima Signup and view all the answers

What is the composition of the tunica adventitia in medium-sized veins?

Dense fibro-elastic connective tissue Signup and view all the answers

What function do the valves in medium-sized veins serve?

Prevent backflow of venous blood towards the heart Signup and view all the answers

What is the percentage of the wall thickness that the tunica media occupies in arterioles?

30% Signup and view all the answers

Which type of blood vessel contains more vasa vasorum in the tunica adventitia, veins or arteries?

Veins Signup and view all the answers

What is the main function of the elastic laminae in the wall of large arteries?

Provide elasticity for inflation during systole Signup and view all the answers

In medium-sized muscular arteries, what is a prominent feature of the tunica intima?

Relatively thin layer Signup and view all the answers

What is the composition of the tunica media in medium-sized muscular arteries?

Predominantly smooth muscle fibers with little elastic and collagen fibers Signup and view all the answers

Which characteristic is true about the tunica adventitia of medium-sized muscular arteries?

Merges into the surrounding connective tissue Signup and view all the answers

What plays a crucial role in providing nutrition to the adventitia and outer part of the media in large arterial walls?

Vasa vasorum Signup and view all the answers

What is the main component of the tunica intima in arteries?

Endothelium Signup and view all the answers

Which layer of the artery constitutes 70% of the wall thickness?

Tunica media Signup and view all the answers

What provides mechanical strength to the wall and controls the luminal diameter of blood vessels?

Smooth muscle Signup and view all the answers

Which layer of the artery contains vasa vasorum, small blood vessels providing nutrition to the vessel wall?

Tunica adventitia Signup and view all the answers

In arteries, what separates the media from the adventitia in many cases?

Thin external elastic lamina Signup and view all the answers

Which type of arteries include the aorta and its large branches?

Large elastic (conducting) arteries Signup and view all the answers

What are small blood vessels called that provide nutrition to the vessel wall?