Page 457 - Atlas of Histology with Functional Correlations

granulocytes and erythrocytes. This hematopoietic capability, however,

ceases after birth. The spleen also serves as an important reservoir for blood.
Because it has a spongelike microstructure, much blood can be stored in its
interior. When needed, the stored blood is returned from the spleen to the
general circulation. Although the spleen performs various important
functions in the body, it is not an essential organ for life.

FIGURE 11.16 | Palatine Tonsil

The paired palatine tonsils consist of aggregates of lymphatic nodules located in

the oral cavity. The palatine tonsils are not surrounded by a connective tissue
capsule. As a result, the surface of the palatine tonsil is covered by a stratified
squamous nonkeratinized epithelium (1, 6) that also covers the rest of the oral
cavity. Each tonsil is invaginated by deep grooves called tonsillar crypts (3, 9)

that are also lined by stratified squamous nonkeratinized epithelium (1, 6).

Below the epithelium (1, 6) in the connective tissue are lymphatic nodules
(2) distributed along the lengths of the tonsillar crypts (3, 9). The lymphatic
nodules (2) frequently merge with each other and usually exhibit lighter-staining
germinal centers (7).

A dense connective tissue underlies the palatine tonsil and forms its capsule
(4, 10). The connective tissue trabeculae, some with blood vessels (8), arise
from the capsule (4, 10) and pass toward the surface of the tonsil between the
lymphatic nodules (2).

Below the connective tissue capsule (10) are sections of skeletal muscle (5)
fibers.

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