196 STUDENTS HISTOLOGY 



OBSERVE : 

 (L.) 



1. The epithelial lining, (a) That it is formed after the 

 transitional type. 



2. The mucosa and its capillary supply. 



3. The dense muscular portion. 



(H.) Fig. 123. 



4. The epithelium, (a) The size of the cells. (&) The layers 

 of the epithelium, which are deep, middle, and superficial, (c) 

 That the deep cells are polyhedral or columnar, (d) The form of 

 the middle cells ; not unlike those of the corresponding region in 

 the ureter, (e) The large, scaly surface epithelial cells. (Note 

 that while these all appear flat, when seen in plan, it is only 

 those of the extreme surface that are simple scales ; the less 

 superficial examples show, when viewed in profile, prolongations 

 from the under surface, by means of which union is effected with 

 the deeper cells.) 



THE URETHRA 



The urethra consists of a mucous coat surrounded by muscular 

 and fibrous tissue. The muscle is unstriated. Numerous papilla 

 cover the surface of the mucous membrane proper. The lining in 

 the female urethra is stratified squamous epithelium. A few small 

 glands are found in the female urethra. The lining of the male 

 urethra varies in the different regions. In the prostatic region it 

 is transitional epithelium , as in the bladder ; in the membranous 

 portion it is stratified columnar ; in the spongy or penile it is 

 simple columnar ; while in the fossa navicularis it becomes strati- 

 fied squamous epithelium, and is continuous with that covering 

 the glans penis. Small, branched, mucous glands (the glands of 

 Littre) occur throughout the male urethra. 



