Spermatogenesis in Humans: Hormonal Regulation, Stages & Sperm Morphology | NEET Biology Core Notes

Welcome to Grip the  Biology , your premier destination for high-quality, NCERT-aligned medical entrance preparation. We take pride in delivering content that doesn't just mirror textbooks but decodes them. This guide on Human Reproduction  is meticulously crafted to meet the rigorous standards of the NTA NEET-UG syllabus, focusing exclusively on the core concepts that matter most."

Before exploring the Reproductive details of the NEET Biology: Spermatogenesis in Humans: Hormonal Regulation, Stages & Sperm Morphology | NEET Biology Core Notes   ensure you have reviewed our previous post  on Human Female Reproductive System - Structure & Diagram and Mammary glands to understand the reproductive context of Human reproduction n the NEET journey.

Table of content: 

• Introduction to Spermatogenesis
• Site of Spermatogenesis & Histology of Testis
• Scheme of Spermatogenesis
• Spermatogenesis vs. Spermiogenesis vs. Spermiation
• Hormonal Regulation (GnRH, LH, FSH & Testosterone)
• Structure & Morphology of Human Spermatozoon
• ​High-Yield Comparison Tables & Matrix Summaries
• NEET & Entrance-Level Practice Questions 

Introduction to Spermatogenesis 

• Spermatogenesis is the biological process by which male primordial germ cells (Spermatogonia)) undergo mitotic and meiotic divisions to produce mature, haploid spermatozoa (n).
• It represents the core event of male gametogenesis, ensuring the precise transmission of paternal genetic material to the next generation while maintaining the species-specific chromosome number (2n = 46 in humans).

​Key Biological Features

• ​Site of Occurrence: It takes place within the seminiferous tubules of the testes.
• ​Onset: Unlike oogenesis (which begins during embryonic development in females), spermatogenesis initiates at puberty under the influence of increased Gonadotropin-Releasing Hormone (GnRH}) levels.
• ​Duration: In humans, the entire process from spermatogonial stem cell to mature spermatozoon—takes approximately 64 to 74 days.
• ​Continuity: It is a continuous, lifelong process that produces hundreds of millions of sperm daily (200 to 300 million} per day in healthy adult males).

​Foundational Terminology

• ​Gametogenesis: The overarching process of gamete formation (Spermatogenesis in males; Oogenesis in females).
• ​Spermatogonia (2n): Diploid stem cells lining the basement membrane of seminiferous tubules that serve as the precursor cells.
• ​Spermatozoa (n): Fully differentiated, functional, motile male gametes.
• ​Ploidy Transition: Diploid ancestral cells (2n = 46) transition to haploid gametes (n = 23) through meiotic reductional division.

💡Read more to understand about the NEET Biology: Male Reproductive System Explained (Diagram, Testes Structure & Duct System)

Site of Spermatogenesis & Histology of Testis 

• ​Spermatogenesis takes place inside the seminiferous tubules present within the testicular lobules of each testis. 
• Each testis has about 250 testicular lobules, and each lobule contains 1 to 3 highly coiled seminiferous tubules.

​Anatomical & Histological Organization

• ​Each seminiferous tubule is lined on its inside by two types of cells that form the germinal epithelium:
• ​Male Germ Cells (Spermatogonia): Diploid precursor cells (2n) that undergo meiotic divisions to form haploid spermatozoa (n).
• ​Sertoli Cells: Large, somatic supporting cells that provide nutrition to the developing germ cells.

 Seminiferous tutule with spermatogonia and Sertoli Cells 

Key Cellular Components (NCERT Highlights)

• ​Sertoli Cells:  These cells act as "nurse cells" anchored to the tubule lining. They nourish developing sperm cells throughout gametogenesis and respond to Follicle Stimulating Hormone (FSH).
• ​Leydig Cells (Interstitial Cells): These are Present in the interstitial spaces outside the seminiferous tubules. Under the influence of Luteinizing Hormone (LH), they synthesize and secrete testicular hormones called androgens (mainly testosterone).
• ​Immunologically Competent Cells: These cells are  present in the interstitial space to provide localized immune protection to the testicular tissue.

​💡 NCERT High-Yield Note:

👉The Leydig cells are located outside the seminiferous tubules (in interstitial spaces), while Spermatogonia and Sertoli cells are located inside the seminiferous tubules.

Scheme of Spermatogenesis 

• ​In the NCERT framework, spermatogenesis starts at puberty and follows a continuous step-by-step pathway from diploid germ cells to functional haploid gametes:

Scheme of Spermatogenesis 

Step-by-Step Breakdown of spermatogenesis

​Step 1 : Spermatogonia (2n):

• These are Primary germ cell and ​Present on the inside wall of seminiferous tubules.
• ​These cells Multiply by mitotic division to increase in number. Each spermatogonium contains 46 chromosomes.

​Step 2 : Primary Spermatocytes (2n):

• ​Some spermatogonia periodically undergo cell enlargement and prepare for meiosis.
• ​They carry 46 chromosomes and undergo the first meiotic division (reductional division).

​Step 3 : Secondary Spermatocytes (n):

• ​These are formed as two equal, haploid cells after Meiosis I.
• ​Each cell contains 23 chromosomes and immediately enters the second meiotic division (equational division).

​Step 4 : Spermatids (n):

• ​These are formed as four equal, haploid cells after Meiosis II.
• ​Each spermatid contains 23 chromosomes but is non-motile and spherical.

​Step 5 : Spermatozoa (n):

• ​Spermatids transform into motile spermatozoa through the process of spermiogenesis.

Cell Type	Ploidy	Chromosome Count	Immediate Division / Process
Spermatogonium	Diploid (2n)	46	Mitosis
Primary Spermatocyte	Diploid (2n)	46	Meiosis I (Reductional)
Secondary Spermatocyte	Haploid (n)	23	Meiosis II (Equational)
Spermatid	Haploid (n)	23	Spermiogenesis
Spermatozoon	Haploid (n)	23	Spermiation

Spermatogenesis vs. Spermiogenesis vs. Spermiation

• ​In my Teaching Experience, These term confuse the students in large frequency. This table will help to clarify this confusion. 

Term	Biological Definition	Starting Cell	Ending Stage
Spermatogenesis	Complete process of converting diploid germ cells into functional haploid spermatozoa.	Spermatogonia (2n)	Spermatozoa (n)
Spermiogenesis	Process of transformation/differentiation of non-motile, spherical spermatids into motile spermatozoa.	Spermatids (n)	Spermatozoa (n)
Spermiation	Process where mature spermatozoa are released from the embedded Sertoli cells into the lumen of seminiferous tubules.	Sperm embedded in Sertoli Cells	Free Sperm in Tubule Lumen

NCERT Key Point: 

During spermiogenesis, spermatids transform into spermatozoa with their heads remaining embedded in the Sertoli cells. After spermiogenesis, sperm heads are released from Sertoli cells by the process called Spermiation.

Hormonal Regulation of Spermatogenesis

• ​Spermatogenesis initiates at puberty due to a significant increase in the secretion of Gonadotropin Releasing Hormone (GnRH) from the Hypothalamus.

Hormonal Roles at a Glance:

• Gonadotropin releasing Hormone  : It is a Hypothalamic Hormone  and acts on the anterior pituitary gland to stimulate secretion of two gonadotropins: Luteinizing Hormone (LH)   and Follicle stimulating Hormone  (FSH) 
• Luteinizing Hormone: This one acts on the Leydig cells and stimulates synthesis and secretion of androgens (Testosterone). Androgens, in turn, stimulate the process of spermatogenesis.

• ​Follicle Stimulating Hormone : This acts on the Sertoli cells and stimulates secretion of some factors which help in the process of spermiogenesis.

Do you know ?  How does make gamete form in Plant ?  Explore the Microsporogenesis, Pollen Grain Structure, and Pollen Allergy | NEET Biology Notes

Structure & Morphology of Human Spermatozoon

• ​A mature human sperm is a microscopic, motile structure composed of four distinct parts wrapped by a continuous plasma membrane: Head, Neck, Middle Piece, and Tail.

A Mature Human Sperm 

Head:  

• It Contains an elongated haploid nucleus. The anterior portion is covered by a cap-like structure called the acrosome.
• ​Acrosome is filled with hydrolytic enzymes (hyaluronidase/sperm lysins) that help in fertilization of the ovum.

Neck: 

• A Short junction connecting head and middle piece; contains proximal and distal centrioles.

​Middle Piece: 

• It Possesses numerous mitochondria coiled spirally around the axial filament.
• It  Produces energy (ATP) for the movement of tail that facilitates sperm motility essential for fertilization.

​Tail: 

• It is a long, slender filament that extends beyond the middle piece and executes vigorous wave-like movement for motility.

NCERT Quantitative Facts for NEET:

• ​Ejaculate Volume & Count: Human male ejaculates about 200 to 300 million sperms during a coitus.

Normal Fertility Requirements:

• ​At least 60% sperms must have normal shape and size.
• At least 40% of them must show vigorous motility.

🎯 NEET MULTIPLE CHOICE QUESTIONS

🔥 100% CHALLENGE

"Questions yahi se aayega... taiyari jeet ki!"

1.  Which of the following statement is not correct.

A. The formation of haploid gamete in   male and female gonad is called gametogenesis.

B. The formation of male gamete in testes is called spermatogenesis.

C. Male and female gamete are diploid.

D. The formation of female gamete in ovaries is called oogenesis 

Answer: C 

2. In testes, the immature male germ cell produce sperms by spermatogenesis  at puberty. The immature germ cell is 

A. Leydig cell

B. Sertoli cell

C. Spermatogonia

D. Nurse cell

Answer : C 

3. Spermatogonia is present inside the wall  in testes at 

A. Interstitial space

B. Seminiferous tubules

C. Near Leydig cell 

D. Tunica albuginea

Answer : B 

4. Consider the following  cells involved in spermatogenesis and arrange them in sequence

1. Prmary spermatocytes

2. Secondary spermatocytes

3. Spermatids

4. Spematozoa

5. Spermatogonia

A. 1- 2- 3- 4- 5

B. 5- 1- 2- 3- 4

C. 1- 3- 2- 5- 4

D. 5- 2- 1- 4- 3

Answer : B 

5. Which of the following statements is not correct about the spermatogonia.

A. Spermatogonia multiply by meiosis division.

B. Spermatogonia divides to ncrease their  numbers. 

C. Each spermatogonium is diploid and contains 46 Chromosomes. 

Some of the spermatogonia called primary spermatocytes. 

Answer : A  

6. Spermatogonia divides by mitosis and form diploid 

A. Primary spermatocytes

B. Secondary spermatocytes

C. Spermatids

D.Spermatozoa

Answer : A 

7. The  primary spermatocyte Complete the first meiotic division and form

A. Secondary spermatocytes

B. Spermatogonia

C. Spermatids 

D. Spermatozoa

Answer : A  

8. Primary spermatocyte divides and form secondary spermatocytes. These are 

A. Equal , haploid and four in number

B. Unequal , haploid and four in number

C. Equal , diploid and two in number

D. Equal , haploid and two in number

Answer: D 

9. Each Secondary spermatocyte divides by second meiotic division  and form spermatids . These are 

A. Equal , haploid and four in number

B. Unequal , haploid and four in number

C. Equal , diploid and two in number

D. Equal , haploid and two in number

Answer: A 

10. Which one of the following during the spermatogenesis contain 46 Chromosomes.

A. Secondary spermatocytes and spermatids

B. Primary Spermatocytes and spermatogonia

C. Spermatids and spermatozoa

D. Spermatids and spermatogonia

Answer: B 

12. Spermiogensis is a process by which transformation takes place from 

A. Primary Spermatocytes to Secondary spermatocyte

B. Spermatogonia to Primary Spermatocytes

C. Secondary spermatocytes into spermatids

D. Spermatids into spermatozoa

Answer : D 

13. Which one of the following statements is incorrect.

A.The spermatids are transformed into spermatozoa (sperms) by the process of spermiogenesis. B. Sperm heads become embedded in the Sertoli cells after spermiogensis.

C. Sperm  are finally released from the seminiferous tubules by the process of

spermiation.

D. Temperature and hormone do not affect the process of spermatogenesis.

Answer : D 

14.  Which one of the following during the spermatogenesis are haploid.

A. Secondary spermatocytes and spermatogonia

B. Primary Spermatocytes and spermatogonia

C. Spermatids and spermatozoa

D. Spermatids and spermatogonia

Answer: C 

15. Spermatogenesis starts at the age of puberty due to significant increase in the secretion of a hypothalamic hormone called

A. Testosterone 

B. Leutinizing hormone

C. Follicle stimulating hormone

D. Gonadotropin releasing hormone( GnRH)

Answer : D 

16. The  increase  levels of GnRH  acts at the anterior pituitary gland and stimulates the secretion of two hormone

A. Androgen and Testosterone

B. LH and FSH

C. Androgen and LH

D. GnRH and FSH

Answer : B 

17. Consider the following statements and select the correct code:

1. FSH acts at the Leydig cells and stimulates synthesis and secretion of androgens.

2. LH acts on the Sertoli cells and stimulates seminiferous tubules to provide the nourishment

A. Only 1.     B. Only 2

C. Both 1 and 2

D. Neither 1 nor 2

Answer : D 

18. Consider the following Diagram and identify and the letter A and B

A. Leutinising Hormone and

Sertoli cell

B. Germ cells and Leutinising

Hormone

C. Seminiferous tubules and Sertoli cell

D. Seminiferous tubules and  male Germ cells

Answer : A  

 19. Consider the following part of sperm covered by the plasma membrane and select the correct code:

1. Head     2. Tail

3. Neck.     4. Middle piece

A. 1 and 2.   B. 1, 3 and 4

C. 1 2 and 4 D. 1,2,3 and 4

Answer : D 

20. The sperm head contain 

A. Nucleus and mitochondria

B. Acrosome and nucleus

C. Mitochondria and Acrosome

D. Nucleus , Acrosome and Mitochondria

Answer : B 

21. Which of the following statements is not correct.

A. The anterior portion of head

is covered by a cap-like structure, acrosome.

B. The acrosome is filled with lytic enzymes that help fertilisation of the ovum.

C. Acrosome is derived from the golgi body.

D.  Acrosome contain numerous mitochondria.

Answer : D 

22. Which part of sperm contain numerous mitochondria.

A. Head     B. Neck

C. Middle Piece. D. Tail

Answer : C 

23. Consider the following statements and select the correct code:

1. Mitochondria produce energy for the movement of tail.

2. Tail  facilitate sperm motility essential for fertilisation.

3. The human male ejaculates about 200 to 300 million sperm.

A.1 and 2       B.  2 and 3

C. 1  2 and 3   D. 1 and 3

Answer : C 

24. For Normal fertility what percentage of sperm must have normal size and shape.

A. 50.   B. 60   C. 70    D. 90

Answer : B 

25. For Normal fertility what percentage of sperm must have vigrous motility.

A. 50.   B. 40   C. 70    D. 90

Answer : B 

26. Spermatogonia - Mitosis - primary Spermatocytes - A - Secondary Spermatocytes - B - Spermatids - Spermatozoa.

Identify the word in place of A and B

A. Mitosis and Mitosis

B. Mitosis and Meiosis

C. Meiosis and Mitosis

D. Meiosis and Meiosis 

Answer : D 

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