Final answer:
The male urethra's epithelial lining changes from transitional epithelium at the bladder, to pseudostratified columnar epithelium through most of the urethra, to nonkeratinizing stratified squamous epithelium at the distal end.
Step-by-step explanation:
The epithelial lining of the male urethra changes from transitional epithelium at the bladder end to pseudostratified columnar epithelium through prostatic, membranous, and most of the penile urethra. This eventually changes to nonkeratinizing stratified squamous epithelium distally.
The transitional epithelium, also known as uroepithelium, is unique to the urinary system and can expand and contract depending on the fullness of the bladder.
It is stratified and appears thicker when the bladder is empty and thinner when it is full. The pseudostratified columnar epithelium gives the appearance of multiple layers due to the varied positioning of nuclei, but in reality, it is a single layer. The stratified squamous epithelium in the distal urethra provides protection against the corrosive effects of urine.