ANS102 Lecture Notes - Lecture 20: Urinary Meatus, Corpus Spongiosum Penis, Male Reproductive System
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Male%Reproductive%System%%
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The$role$of$the$male$reproductive$system$is$to$produce$sperm$and$
to$inseminate$females$in$order$to$achieve$fertilisation$
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Testes%
• The$tunica$albuginea$projects$internally$into$the$testes$to$
form$septa$
• 2$main$fucntions$are$to$produce$sperm$and$hormones$$
• The$septa$subdivide$to$form$about$250$lobules$
• Each$lobule$contains$four$convoluted$seminiferous$tubules$
- Sustentacular$cells—nondividing$support$cells$that$
assist$with$sperm$development;$connected$to$each$
other$by$tight$junctions$and$form$the$blood@testis$
barrier$
- A$population$of$dividing$germ$cells$that$continuously$
produces$sperm$beginning$at$puberty$$
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Scrotum%
• The$scrotum$is$a$skin@covered$sac$
that$houses$the$testes.$
• Sperm$develop$successfully$at$
approximately$3°$Celsius$below$
normal$body$temperature.$
• The$dartos$muscle$is$a$layer$of$
smooth$muscle$that$is$part$of$the$
wall$of$the$scrotum.$
- Cremaster$muscle$(external)$–$a$
strip$of$striated$muscle,$
originating$from$the$abdomen$
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Ejaculation%and%Erections%%
• The$erectile$bodies$are$composed$of$
venous$spaces,$which$fill$with$blood$
from$a$central$artery$to$produce$an$
erection$$
• Parasympathetic$innervation$
responsible$for$penile$erection$
(engorgement$and$rigid$through$blood$
flow)$$
• Sympathetic$innervation$promotes$
ejaculation$(stimulation)$
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Penis%%
• The$shaft$of$the$penis$is$comprised$of$three$parallel,$
cylindrical$erectile$bodies:$
- Paired$corpora$cavernosa$are$located$$dorsolaterally$
and$terminate$at$the$distal$shaft$of$the$penis.$
- A$single$corpus$spongiosum$is$inferior$and$midline$and$
surrounds$the$spongy$urethra.$
- The$distal$end$of$the$corpus$spongiosum$continues$
within$the$glans.$
• The$tip$of$the$penis$is$the$glans,$which$surrounds$the$
external$urethral$orifice$
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