Statement I: The release of sperms into the seminiferous tubules is called spermiation. Statement II: Spermiogenesis is the process of formation of sperms from spermatogonia.

Statement I is correct but Statement II is incorrect

Statement I is incorrect but Statement II is correct

Both Statement I and Statement II are correct

Both Statement I and Statement II are incorrect

The difference between spermiogenesis and spermiation is

in spermiogenesis spermatozoa are formed, while in spermiation spermatozoa are released from Sertoli cells into the cavity of seminiferous tubules.

in spermiogenesis spermatozoa from Sertoli cells are released into the cavity of seminiferous tubules, while in spermiation spermatozoa are formed.

in spermiogenesis spermatozoa are formed, while in spermiation spermatids are formed.

in spermiogenesis spermatids are formed, while in spermiation spermatozoa are formed.

Spermatogenesis

விந்தணு உருவாக்கம்

NCERT Class 12 · Human Reproduction · 3 NEET questions

Spermatogenesis is not just cell division; it is a metabolic marathon. Most students fail to distinguish between spermatogenesis and spermiogenesis. If you confuse the two, you lose four marks instantly.

The idea

Spermatogenesis occurs in the seminiferous tubules at puberty. Spermatogonia (diploid) undergo mitosis to increase in number, then primary spermatocytes undergo meiosis I to form secondary spermatocytes (haploid). These undergo meiosis II to form spermatids, which finally transform into spermatozoa through spermiogenesis. Hormonal control involves GnRH, LH, and FSH acting on Leydig and Sertoli cells.

Why it matters

To continuously produce male gametes required for sexual reproduction throughout the male reproductive life.

NEET lens

NEET focuses on the ploidy of cells at each stage: spermatogonia (2n), primary spermatocyte (2n), secondary spermatocyte (n), and spermatid (n). Memorize the sequence of cell types and the specific role of FSH on Sertoli cells. Expect questions on the distinction between spermiogenesis and spermiation.

Clinical significance

Failure in spermatogenesis leads to oligospermia or azoospermia, the primary causes of male infertility. Factors like cryptorchidism or exposure to high temperatures disrupt the process, as the testes require a temperature 2-2.5°C lower than body temperature for optimal function.

Introduction

Spermatogenesis is the formation of spermatozoa (sperm) from spermatogonia in the seminiferous tubules of the testes, involving mitosis, meiosis, and spermiogenesis (sperm maturation), producing ~300 million sperm per day in humans.

Core concept

Stages: (1) Spermatocytogenesis: spermatogonia (2n, stem cells) → mitosis → some remain as stem cells, some become primary spermatocytes (2n). (2) Meiosis I: primary spermatocyte (2n) → 2 secondary spermatocytes (n). (3) Meiosis II: each secondary spermatocyte → 2 spermatids (n). Total: 1 spermatogonium → 4 spermatids. (4) Spermiogenesis: spermatid (round) → spermatozoon (mature sperm) — acrosome formation (from Golgi), flagellum development (from centriole), nucleus condenses, cytoplasm shed as residual body. Sertoli cells nurture developing sperm. Leydig (interstitial) cells produce testosterone (LH-stimulated). Duration: ~64 days in humans. Location: seminiferous tubules → epididymis (maturation and storage).

Go deeper

Blood-testis barrier (BTB): tight junctions between Sertoli cells divide seminiferous tubule into basal (spermatogonia) and adluminal (meiotic cells) compartments. BTB: (1) Protects developing sperm from immune attack (sperm antigens are novel — not present during immune system education). (2) Maintains ionic environment optimal for meiosis. Breakdown of BTB → autoimmune orchitis → infertility.

From Class 10

Spermatogenesis is the process by which the testes continuously produce millions of sperm cells (spermatozoa) from puberty onwards.