Page 409 - Atlas of Histology with Functional Correlations

muscular artery, the tunica media (1b), contains several layers of smooth

muscle fibers, arranged in a circular pattern, and thin dark strands of elastic
fibers (1b). On the periphery of the tunica media (1b) is the less conspicuous
EEL (1c). Surrounding the artery is the connective tissue tunica adventitia
(1d), which contains both the light-staining collagen fibers (2) and the dark-
staining elastic fibers (3).

The wall of the vein (4) also contains the layers tunica intima (4a), tunica
media (4b), and tunica adventitia (4c). However, these three layers in the vein
(4) are not as thick as those in the wall of the artery (1).

Surrounding both vessels are the capillary (5), arteriole (7), venule (6), and

cells of the adipose tissue (8). Present in the lumina of both vessels (1, 4) are
numerous erythrocytes and leukocytes.

FIGURE 10.8 ■ Muscular artery and vein (transverse section). Stain: elastic
stain. Low magnification.

FIGURE 10.9 | Artery and Vein in Dense

Irregular Connective Tissue of Vas Deferens

This photomicrograph illustrates the differences between a small artery (1) and
a small vein (6) in dense irregular connective tissue (5). The small artery (1) has
a thick muscular wall and a small lumen. The arterial wall consists of the tunica
intima (2), composed of an inner layer of endothelium (2a), a subendothelial

(2b) connective tissue, and an IEL (membrane) (2c). This membrane (2c)
separates the tunica intima (2) from the layer of circular smooth muscle fibers of

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