Normal histology : a manual for students and practitioners / by John R. Wathen.

  • Wathen, John Roach, 1872-
Date:
[1905]
Catalogue details

Licence: In copyright

Credit: Normal histology : a manual for students and practitioners / by John R. Wathen. Source: Wellcome Collection.

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    veins, having a lining of endothelium, and in the larger vessels muscular and fibrous outer coats. The lymph-capillaries are not, like the blood-capillaries, intermediate structures between the two systems, but they form the lymphatic system which empties into the vascular system. Lymphoid or adenoid tissue is a delicate connective-tissue reticulum containing the small round lymphoid cells and communicating with the lymphatic vessels. Diffuse adenoid tissue occurs in the mucosae of the digestive and respiratory tracts. The simple lymphatic nodides ov follicles consist of spherical masses of lymphatic tissue, having a connective-tissue cap- sule and well supplied with lymph-vessels. The tissue is most dense at the periphery of the gland. These lymph- glands are found along the course of the lymphatic vessels and are grouped together in the neck, axilla, groin, etc. The spleen is a compound lymphatic gland with a special blood-sup])ly opening into its reticular spaces. This organ is often called a ductless gland, as it differs from most of the glands of the body in not having an excretory channel. The gland or organ is covered with a dense cap- sule, of an outer serous and an inner fibroelastic coat, from which fibrous bands or trabeculae are given off, which pene- trate the lymphatic tissue or splenic pulp, as it is called. These trabeculae constitute the framework of the spleen. This capsule also eon tains a few non-striated muscle-fibres. The arteries enter the organ at the hilum, and, after pene- trating its capsule, follow the trabeculae. Spherical masses of dense adenoid tissue, called the Mcd- pighian corpuscles, appear throughout the gland, and these ensheath the arteries. The arteries lack tlie characteristic arrangements seen in other organs, and the blood appears to be emptied into the pulpy structure to be changed or regen- erated, and then filtered into the veins of the spleen. The circulation in the spleen is best considered together with the so-called lobide (Mall). The spleen is thus divided into sacs, each containing a spleen-lobule. The Malpighian corpus-