Lecture 27: CV Histology

Question 1

List the 3 layers (tunics) of the heart wall and describe the major characteristics of each layer:

Answer 1

1. Endocardium: innermost ; endothelium and subendothelial CT
2. Myocardium: cardiac muscle cells
3. Epicardium: outermost. Simple squamous epithelium.

Question 2

compare the characteristics of each of the 3 tunics.

Answer 2

Tunica intima: endothelium and basal lamina. -in all arteries and arterioles, elastic and muscular arteries . Incomplete in elastic arteries.

Tunica media: made of circular smooth muscle tissue and fibroblasts. Contains collagen and elastic fibers.

Tunica adventitia: outermost layer. Lacking in arterioles. Consists loose areolar tissue. Irregular fibroelastic tissue w/ adipocytes. Hard small vessels and nerves.

Question 3

Check figure 12-13 and note the following: role of prostacyclin in the prevention of blood clot formation and as a vasodilator and the role of NO and endothelin in modulating smooth muscle cell activity.

Answer 3

role of prostacyclin in the prevention of blood clot formation:

role of prostacyclin as a vasodilator:

the role of NO and endothelin in modulating smooth muscle cell activity:

***not test question!!

Question 4

For each type of vessel (elastic artery, muscular artery, arteriole, and vein) describe the 3 tunics

Answer 4

Elastic arteries: conducting artery. Stretch during systole. 40 layers in newborn, 70 in adult. CT interspersed btw elastic laminae. [aorta,pulmonary trunk, large branches of aorta]

Muscular arteries: distributing arteries-how much blood goes to each part of the body. Thickness of smooth muscle layer decreases as diameters becomes smaller. Gradual transition from elastic artery to muscular artery. [all arteries but elastic]

Arterioles:thickness of smooth muscle layer decreases as diameters becomes smaller. Final distributing elements of blood flow.

Veins: compared w. Ateries: larger lumen, thinner wall, and valves are present in many veins. Layer of longitudinal smooth muscle in tunica adventitia.

Question 5

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Answer 5

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Question 6

Identify atheroma and foam cells from pics:

Answer 6

K

Question 7

Capillaries / leafiness:

Answer 7

Continuous: alveolus, no holes. Only pores for gas exchanges..tight junctions

Fenestrated: glomerulus

Discontinuous: spleen, GAPs