Human Anatomy: Types of Arteries

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Questions and Answers

Which type of artery possesses a thick tunica media with 40-70 layers of elastic lamina?

Large (elastic) artery (correct)

Small artery

Arteriole

Medium-sized artery

What is the primary function of arterioles in the circulatory system?

Transporting oxygenated blood

Nutrient absorption

Regulating blood pressure (correct)

Waste elimination

Which layer of blood vessels contains smooth muscle and is responsible for vasoconstriction and vasodilation?

Tunica adventitia

Tunica intima

Tunica media (correct)

Endothelium

What structural feature differentiates small arteries from arterioles?

Presence of an internal elastic lamina Signup and view all the answers

What structure surrounds the endothelial cells in capillaries and assists in their function?

Pericyte Signup and view all the answers

Which type of blood vessel has vasa vasorum present in its tunica adventitia?

Large (elastic) arteries Signup and view all the answers

What is the average diameter of a capillary?

8 um Signup and view all the answers

Which of the following statements is true regarding the tunica layers in blood vessels?

The tunica adventitia contains connective tissue and nerve tissue. Signup and view all the answers

What is the primary function of arteries in the circulatory system?

They deliver blood from the heart to body tissues. Signup and view all the answers

Which layer of blood vessels is responsible for the contraction and dilation of arteries?

Tunica media Signup and view all the answers

What distinguishes veins from arteries in terms of structure?

Veins have a larger lumen and thinner walls. Signup and view all the answers

What role do vasa vasorum serve in blood vessels?

They supply nutrients to the vessel walls. Signup and view all the answers

Which type of capillary is best suited for rapid exchange due to its porous structure?

Fenestrated capillary Signup and view all the answers

Which tunica layer provides structural support through connective tissue?

Tunica adventitia Signup and view all the answers

What is a key structural feature of the tunica intima in arteries?

Presence of an internal elastic membrane Signup and view all the answers

What is the main function of capillaries in the circulatory system?

Facilitate nutrient and waste exchange between blood and tissues. Signup and view all the answers

Which type of capillary is characterized by the presence of tight junctions and no pores?

Continuous capillary Signup and view all the answers

What is a defining feature of sinusoids compared to other types of capillaries?

Large intercellular clefts Signup and view all the answers

Which statement correctly describes the tunica media of veins?

It has fewer smooth muscle layers compared to arteries. Signup and view all the answers

Which type of capillary is most likely found in the kidney glomerulus?

Fenestrated capillary Signup and view all the answers

What is the primary function of the vasa vasorum in blood vessels?

To supply blood to the walls of large vessels Signup and view all the answers

In veins, valves are primarily responsible for which of the following functions?

Preventing blood from flowing backward Signup and view all the answers

Which of the following best describes the structure of a fenestrated capillary?

Endothelial cells with large perforated pores Signup and view all the answers

What is true regarding the tunica adventitia in large veins?

It contains smooth muscle arranged longitudinally. Signup and view all the answers

Study Notes

Large (Elastic) Artery

Examples include the aorta, pulmonary trunk, and their main branches.
Large lumen (diameter greater than 10mm) relative to wall thickness.
Thick subendothelial layer with a few smooth muscles.
Thick tunica media containing 40-70 concentrically arranged elastic lamina.
Internal and external elastic lamina are indistinct.
Thinner tunica adventitia with abundant vasa vasorum.

Medium-Sized Artery

Also known as muscular artery.
Diameter between 2mm -10mm.
Distinct internal elastic lamina, while the external elastic lamina is not clearly defined.
Tunica media contains 10 - 40 layers of circular smooth muscles.
Tunica adventitia contains loose connective tissue with vasa vasorum and nerve tissue.

Small Artery

Diameter between 0.1mm - 2mm.
Clear internal elastic lamina, but indistinct external elastic lamina.
The tunica media contains 3 - 9 layers of smooth muscle.

Arterioles

Less than 0.1mm in diameter.
Have similar structure to muscular arteries, though simpler.
Tunica media contains 1-2 layers of smooth muscle.
Responsible for blood pressure regulation.
Thin tunica adventitia in both small arteries and arterioles.

Capillaries

The site of exchange between blood and tissues.
Capillaries form networks in many organs.
Consist of a single layer of simple squamous epithelium, with an average diameter of 8um.

Capillaries - Structure

Composed of a single layer of endothelial cells.
Possess a basement membrane.
Surround by pericytes, which have long cytoplasmic processes that surround the endothelial cells.

Types of Capillaries

Continuous capillary: Distributed in muscle tissues, brain, lungs, and connective tissues. Characterized by large numbers of pinocytotic vesicles, tight junctions between endothelial cells, and no pores or gaps. Has an intact basement membrane.
Fenestrated Capillary: Distributed in tissues where rapid exchange of substances between blood and tissue occurs (e.g., kidney glomerulus, gastrointestinal mucosa, endocrine glands). Possesses perforated pores in the endothelial cells with or without diaphragms. Intact basement membrane.
Sinusoid: Found in tissues requiring large exchange of substances (e.g., liver, spleen, some endocrine glands). Enlarged diameter (30-40um), large intercellular clefts between endothelial cells, many pores without diaphragms. Lacks a continuous basement membrane, and contains macrophages amongst the endothelial cells.

Veins

Large lumen, thin wall, irregular.
Internal and external elastic lamina are not clearly distinguished.
Thin tunica media with a few elastic fibers and smooth muscles.
Thick (well-developed) tunica adventitia.
Some veins possess valves.

Large Veins

Diameter greater than 10mm.
Tunica media composed of 3 - 15 layers of smooth muscle.
Well-developed tunica adventitia with longitudinally arranged smooth muscle cells, adipose tissue, and vasa vasorum.
Contain valves.

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Description

This quiz covers the characteristics and classifications of large, medium-sized, small arteries, and arterioles. Test your knowledge on their structural features and differences. Ideal for students studying human anatomy.