Page 486 - Atlas of Histology with Functional Correlations

A higher-magnification photomicrograph shows the different cell layers in the

epidermis (1) of the thick skin of the palm. The outermost and the thickest layer
is the stratum corneum (1a). Inferior to the stratum corneum (1a) are two to
three layers of cells filled with dark granules. This is the stratum granulosum
(1b). Below the stratum granulosum (1b) is the stratum spinosum (1c), a
thicker layer of polyhedral cells. The deepest cell layer in the epidermis (1) is the

stratum basale (1d). The cells in this layer contain brown melanin granules
(6). The stratum basale (1d) is attached to a thin connective tissue basement
membrane (4) that separates the epidermis (1) from the dermis (2). The

connective tissue of the dermis (2) indents the epidermis (1) to form dermal
papillae (5). Passing through the dermis (2) and all cell layers of the epidermis
(1) is the excretory duct (3) of a sweat gland that is located deep in the dermis.

FIGURE 12.9 ■ Thick skin: epidermis and superficial cell layers. Stain:
hematoxylin and eosin. ×40.

FIGURE 12.10 | Apocrine Sweat Glands:

Secretory and Excretory Portions of Sweat Gland

The apocrine glands are large, coiled sweat glands that deliver their secretions
into the hair follicle (7). This illustration shows cross sections of an apocrine
sweat gland and secretory units of an eccrine sweat gland for comparison. The

secretory portion of the apocrine sweat gland (3) consists of wide and dilated
lumina. The gland is located deep in the connective tissue of the dermis (5) or
hypodermis with adipose cells (4) and numerous blood vessels (8). In
comparison, the secretory portion of an eccrine sweat gland (6) is smaller and

485