STRUCTURE OF MUCOUS MEMBRANES. 



207 



foi-m — and, in. many parts, non-striated muscular tissue, variously 

 disposed. The nerves also which belong to the mucous membrane are 

 distributed in this part of its structure ; in some parts, the palate and 



Fig. 137. 



Fig. 137. — Tubular Gl.\nd with adjacent Lt.mphoid Tissue, fkom Intestine of 

 Rabbit (Verson). HiGHLr magnified. 



K, lumen of gland ; a, a, epitlielium with thickened striated border ; d, lymphoid 

 tissue, from which most of the corpuscles have been removed. Between this and the 

 epithelium is seen the basement-membrane, b, in section. T, more condensed connective- 

 tissue of the mucoiis membrane. 



vagina for instance, minute branches of the nerves have also been traced 

 extending between and amongst the epithelium cells. 



The vessels exist almost universally in mucous membranes. The 

 branches of the arteries and veins, dividing in the submucous tissue, 

 send smaller branches into the corium, which at length form a network 

 of capillaries in the fibro-vascular layer. This capillary network lies 

 immediatel}' beneath the epithelium, or the basement-membrane when 

 this is present, advancing with that membrane into the villi and 

 papillae to be presently described, and surrounding the tubes and other 

 glandular recesses. The lymphatics also form networks, which com- 

 municate with plexuses of larger vessels in the submucous tissue ; 

 their arrangement generally, as well as in the villi, has been already 

 noticed. 



The fibres of connective tissue which enter into the formation of the 

 corium are both the white and the elastic. The former are arranged in 

 interlacing bundles, the elastic commonly in networks ; but the amount 



