Page 348 - Veterinary Histology of Domestic Mammals and Birds, 5th Edition

330 Veterinary Histology of Domestic Mammals and Birds

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15.10 Epidermis and stratum papillare of the skin (horse). Haematoxylin and eosin stain (x32).

The plasticity and deformability of the skin is attribut- Hypodermis (subcutis)
able largely to the abundance of elastic fibres that enable The hypodermis is composed of loose, irregularly
the collagen lamellae to resume their original arrangement arranged connective tissue. It forms a mobile connection
after stretching. The reticular layer is relatively poorly vas- between the skin and the fascia or muscles (Figure 15.11).
cularised. It is populated primarily by small arteries and Distinguishing features include:
veins passing to and from more superficial layers.
The dermis exhibits considerable regional and species- · a network of blood vessels,
related variation in thickness. Additional factors affecting · variable quantities of adipose tissue and
the development of the dermis include functional load, · embedded striated muscle tissue.
climate and breed. Among domestic mammals, the dermis
is thickest in cattle. In leather production (tanning), the The subcutis is vascular and rich in adipose tissue. The
elastic skin of young animals is more suitable than that of degree of fat accumulation in this layer varies with species,
older animals. gender and body region. Fat deposits act as energy reserves
and provide thermal insulation. In parts of the body

15.11 Deep layers of the skin (horse). Haematoxylin and eosin stain (x16).

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