Wk.8 L2 - Histology of Heart and Vessels 1

Question 1

Describe the general structure of blood vessel walls.

Answer 1

Blood vessel walls consist of three layers: tunica intima, tunica media, and tunica adventitia.

Question 2

What are the three layers of a blood vessel wall?

Answer 2

Tunica intima, tunica media, and tunica adventitia.

Question 3

What are the components of the tunica intima?

Answer 3

Endothelium, basal lamina, and a thin layer of connective tissue.

Question 4

What are the components of the tunica media?

Answer 4

Smooth muscle cells and elastic fibers.

Question 5

What are the components of the tunica adventitia?

Answer 5

Collagen, elastic fibers, fibroblasts, and nerves; may include some smooth muscle.

Question 6

What type of cells line all blood vessels?

Answer 6

Simple squamous endothelial cells.

Question 7

How do arteries differ from veins in terms of wall structure?

Answer 7

Arteries have a thick tunica media with elastic fibers and smooth muscle, while veins have thinner walls, a larger lumen, and a thick tunica adventitia.

Question 8

What are the characteristics of arteries compared to veins regarding lumen shape and wall thickness?

Answer 8

Arteries have a small, regular lumen and thick walls; veins have a large, irregular lumen and thin walls.

Question 9

What is the internal elastic membrane?

Answer 9

A distinct elastic layer separating the tunica intima and media, prominent in arteries.

Question 10

How do the walls of elastic arteries differ from muscular arteries?

Answer 10

Elastic arteries are rich in elastic fibers within the tunica media, whereas muscular arteries have a tunica media dominated by smooth muscle.

Question 11

Which type of artery is rich in elastic fibers?

Answer 11

Elastic arteries.

Question 12

Which type of artery is dominated by smooth muscle in its wall?

Answer 12

Muscular arteries.

Question 13

What is the role of smooth muscle in the tunica media?

Answer 13

It regulates vessel diameter and blood pressure.

Question 14

What is the function of elastic fibers in the vessel wall?

Answer 14

They provide resilience and allow the vessel to accommodate pulsatile blood flow.

Question 15

Describe the structure and function of arterioles.

Answer 15

Arterioles are small vessels (30-200 µm diameter) with 1-2 layers of smooth muscle that control peripheral vascular resistance.

Question 16

What is the typical diameter range of arterioles?

Answer 16

Approximately 30 to 200 micrometers.

Question 17

How do arterioles contribute to peripheral vascular resistance?

Answer 17

By regulating smooth muscle contraction, which alters the lumen diameter.

Question 18

What are the general characteristics of veins?

Answer 18

Veins have thinner walls, a larger and often irregular lumen, and a thick tunica adventitia; they may contain valves.

Question 19

How are the layers arranged in veins?

Answer 19

The tunica intima is thin, the tunica media has few smooth muscle layers, and the tunica adventitia is the thickest layer.

Question 20

Why do veins have a larger lumen compared to arteries?

Answer 20

Because their walls are thinner and they function at lower pressure to accommodate larger blood volumes.

Question 21

What is a key feature of the tunica adventitia in veins?

Answer 21

It is the thickest layer, composed mainly of collagen and elastic fibers.

Question 22

What are venules and what is their typical diameter?

Answer 22

Venules are small venous vessels with diameters ranging from 10 to 50 micrometers.

Question 23

What additional structure may be present in veins that is usually absent in arteries?

Answer 23

Venous valves.

Question 24

What are venous valves and what is their function?

Answer 24

Structures that prevent backflow and ensure unidirectional blood flow in veins.

Question 25

How do varicose veins develop with respect to venous valves?

Answer 25

Valve failure leads to blood pooling and venous wall remodeling, resulting in varicosities.

Question 26

Name a molecule that may be expressed during venous wall remodeling.

Answer 26

ICAM-1 or E-selectin.

Question 27

How does shear stress affect gene expression in veins?

Answer 27

It induces expression of inflammatory molecules such as TNF and IL-1.

Question 28

Which histology reference is mentioned for this lecture?

Answer 28

Pawlina, 'Histology: a text and atlas' (8th edition).

Question 29

How is the endothelium in blood vessels characterized?

Answer 29

It is formed by a continuous layer of simple squamous cells that provide a smooth surface for blood flow.

Question 30

What are fibroblasts and what role do they play in vessel walls?

Answer 30

Fibroblasts produce collagen and elastic fibers, contributing to the structural support of the tunica adventitia.

Question 31

What does the term 'junctional complex' refer to in endothelial cells?

Answer 31

It refers to the specialized cell-cell connections that maintain the integrity of the endothelial lining.

Question 32

How do nerves contribute to the structure of vessel walls?

Answer 32

Nerves in the tunica adventitia help regulate vascular tone.

Question 33

What are the main connective tissue components found in the tunica adventitia?

Answer 33

Collagen and elastic fibers.

Question 34

What is the primary function of smooth muscle cells in regulating vessel diameter?

Answer 34

They constrict or dilate to control blood flow and pressure.