Order of ducts in the male reproductive system, and Sertoli vs Leydig cells: where do they actually sit?
Zoya Khan12th Sample
12 Sept 2026 · 1 min read
I am revising Human Reproduction slowly, one section a day, because I get overwhelmed when I read the whole chapter in one go. Today was the male reproductive system, and my diagram has so many labels that I started to feel they were swimming around the page 😅
What I have clear: testes are in the scrotum outside the abdomen. Each testis has testicular lobules, and the lobules contain seminiferous tubules where sperms are formed. There are accessory glands and ducts.
What isn't clear is the sequence. I wrote "seminiferous tubules → vas deferens → urethra" at first and then added other names in between, but I'm not sure of the order of rete testis, vasa efferentia and epididymis. Also, NCERT says the seminiferous tubule is lined by male germ cells and Sertoli cells, and the interstitial spaces outside the tubule have Leydig cells. I can recite it but I don't see what each cell does for the sperm, and what the hormones have to do with it.
And last, why are testes outside the body? My notes say "temperature" but not how much lower. Can someone give the path in a way that I can reproduce on an exam paper without panicking?
8 answers & replies
Sign in to join the conversation.
[+][–]Rahul DubeyDropperSample· 1mo ago
The path of the sperm, in one breath:
Seminiferous tubules → rete testis → vasa efferentia → epididymis → vas deferens → ejaculatory duct → urethra → urethral meatus
The vas deferens goes up into the abdomen, loops over the urinary bladder and joins the duct of the seminal vesicle to form the ejaculatory duct, which opens into the urethra. The urethra starts at the bladder and runs through the penis, so it carries both urine and semen, but not at the same time. Write the arrows, it is worth full marks in a flowchart question.
[+][–]Zoya Khan12thSample· 1mo agoAuthor
the flowchart is going on a sticky note on my desk. thank you all, especially for the Diya/scrotum correction, I would have written the same thing
[+][–]Kavya NaikDropperSample· 1mo ago
Cells: Sertoli cells are inside the seminiferous tubules, next to the germ cells, and they give nutrition to the developing germ cells (the "nurse cells"). Leydig cells (interstitial cells) are outside the tubules, in the small spaces between tubules where there are blood vessels, and they make androgens, mainly testosterone.
Hormone link: LH from the pituitary acts on Leydig cells so they secrete androgens, and the androgens stimulate spermatogenesis. FSH acts on Sertoli cells, which then secrete some factors that help the process of spermiogenesis (conversion of spermatids into sperms). So sperm production needs both.
[+][–]Diya Menon11thSample· 1mo ago
I'm in class 11 so I might be wrong but I think the scrotum keeps the testes warmer? Like a pouch to protect them in the cold? Because sperm need body temperature?
[+][–]Lakshmi TripathiDropperSample· 1mo ago
Opposite, Diya. The scrotum keeps the testes about 2 to 2.5 °C lower than the normal internal body temperature, and that is the temperature needed for spermatogenesis. If it gets too warm, sperm production suffers. That's why NCERT says the testes are in the scrotum, and the scrotum acts like a cooling system.
[+][–]Tushar PawarDropperSample· 1mo ago
so scrotum is basically a heat sink with a fan, got it. nature's CPU cooler. (also I'm JEE, I just came here because the thread title looked like a pipeline diagram lol)
[+][–]Tanvi Deshmukh12thSample· 1mo ago
Accessory glands!! There are three kinds: a pair of seminal vesicles, one prostate and a pair of bulbourethral glands. Their secretions together make the seminal plasma, which is rich in fructose (energy for the sperm), calcium and some enzymes. The bulbourethral glands' secretion also helps in lubrication of the penis. The end of the penis is the glans penis, covered by a loose fold of skin, the foreskin.
Do not miss: duct side = tubes that carry (rete testis, vasa efferentia, epididymis, vas deferens, ejaculatory duct, urethra). Gland side = three that add fluid.
[+][–]Siddharth RaoDropperSample· 1mo ago
Numbers that NCERT gives and examiners like: each testis has about 250 compartments (testicular lobules), and each lobule contains 1 to 3 highly coiled seminiferous tubules. And the epididymis is where the sperms get stored and gain motility, so that's a common one: "where do sperms become motile?"
