A seminiferous tubule is the tiny coiled tube inside the testis where sperms are made. Its inner wall (lining) has only two cell types: male germ cells (spermatogonia) and Sertoli cells. The Leydig cells are NOT inside the tubule; they sit OUTSIDE it in the interstitial space. Memory hook: "INside = Germ + Sertoli; OUTside = Leydig."
Inside the tubule wall: spermatogonia (male germ cells) and Sertoli cells. Outside, in the interstitial space: Leydig cells with blood vessels. Sperms are released into the central lumen.
Your doubts, answered
Which two cells line the INSIDE of a seminiferous tubule?
Only two: male germ cells (spermatogonia) and Sertoli cells. NCERT says each seminiferous tubule is lined on its inside by these two types of cells. Leydig cells are NOT part of this lining.
Are Leydig cells inside or outside the seminiferous tubule?
OUTSIDE. Leydig cells (also called interstitial cells) lie in the interstitial spaces BETWEEN the tubules, along with small blood vessels. This is a very common NEET trap - do not place them in the lining.
What is the difference between spermatogonia and Sertoli cells?
Spermatogonia are the male germ cells that undergo meiotic divisions to finally form sperms. Sertoli cells are the tall support cells that provide nutrition to the germ cells and hold sperm heads before spermiation. Germ cells become sperm; Sertoli cells feed them.
What is present in the interstitial space of the testis?
The regions outside the seminiferous tubules (interstitial spaces) contain small blood vessels, interstitial cells (Leydig cells) that secrete androgens, and other immunologically competent cells.
Where are sperms actually produced?
Inside the seminiferous tubules. Each testicular lobule contains one to three highly coiled seminiferous tubules in which sperms are produced. The testis has about 250 such lobules.
Do Sertoli cells produce testosterone?
No. Sertoli cells provide nutrition and respond to FSH; Leydig cells (in the interstitial space) secrete androgens like testosterone under LH. Mixing this up is a frequent NEET error.
⚠️ The NEET trap ✗ FSH acts on the Leydig cells and the interstitial cells lie inside the seminiferous tubule. ✓ In males FSH acts on the Sertoli cells (inside the tubule lining); LH acts on the Leydig cells, which lie OUTSIDE the tubule in the interstitial space and secrete androgens. 🧠 FSH -> Sertoli (inside), LH -> Leydig (outside). Sound-match: FSH+Sertoli both have 'S'.
Real NEET questions
2024
Assertion A: FSH acts upon ovarian follicles in female and Leydig cells in male. Reason R: Growing ovarian follicles secrete estrogen in female while interstitial cells secrete androgen in male human being.
A · Both A and R true but R is NOT the correct explanation of A
B · A is true but R is false
C · A is false but R is true ✓
D · Both A and R are true and R is the correct explanation of A
Solution: Reason R is true: growing ovarian follicles secrete estrogen, and interstitial (Leydig) cells secrete androgens. Assertion A is false: in males FSH acts on Sertoli cells (inside the tubule), NOT Leydig cells; LH acts on Leydig cells. So A is false but R is true. This tests knowing that Leydig/interstitial cells sit outside the tubule and make androgen.
Solved Human Reproduction NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
How many seminiferous tubules are in each testicular lobule?
Each testicular lobule contains one to three highly coiled seminiferous tubules, and each testis has about 250 lobules.
What is the function of Sertoli cells in the tubule?
Sertoli cells provide nutrition to the dividing germ cells. Sperm heads become embedded in them before being released (spermiation), and they respond to FSH.
What do Leydig cells secrete?
Leydig cells (interstitial cells) synthesise and secrete testicular hormones called androgens, mainly testosterone, under the control of LH.
Why is 'seminiferous tubule lined by Leydig cells' wrong?
Because Leydig cells lie in the interstitial space OUTSIDE the tubule. Only spermatogonia and Sertoli cells line the inside of the tubule.
