Male reproductive system slideshare.pptx

Male reproductive system parts and its function and sperm

1. Male reproductive system By Dr.Pavithra Pharm.D

2. Male Reproductive System

3. To produce the gametes ,sperms and ova To transport and sustain these gametes To nurture the developing offspring To produce hormones Functions of Male & Female reproductive system

4. External Genital organs Penis Scrotum Internal Genital organs Testis Epididymis Vas Deferens Accessory Glands a. Seminal Vesicles b.Prostate Gland c.Bulbourethral glands

5. The penis is the male organ of copulation (Sexual intercourse) and urination. It consists of three parts: the root, the body (shaft), and the glans (tip). The shaft of the penis contains erectile tissue, including the two corpus cavernosa and the corpus spongiosum , which fill with blood during sexual arousal, leading to an erection. The glans of the penis is highly sensitive and contains the external opening of the urethra, through which both urine and semen exit the body. Penis

6. Erectile Tissues Corpus spongiosum Made up of spongy erectile tissue that contains a network of blood vessels, smooth muscle fibers, and connective tissue. It has a more open and porous structure compared to the denser corpus cavernosa . The corpus spongiosum surrounds the urethra and extends from the base of the penis to the glans (the tip of the penis). Main roles : Spongy tissue helps keep the urethra open during different situations. For example , when a guy gets an erection, the corpus spongiosum helps keep the urethra open so that urine and semen can pass without any blockages.

7. Corpus cavernosa Each corpus cavernosum is composed of spongy erectile tissue made up of a network of blood vessels, smooth muscle fibers, and connective tissue. The tissue has a honeycomb-like structure with large spaces that can fill with blood during an erection.

8. Eg : When a guy becomes aroused, these tubes fill up with blood, causing the penis to become bigger, longer, and harder. This is what creates an erection. The corpus cavernosa is responsible for the stiffness and firmness of the penis during sexual arousal. The corpus spongiosum works in conjunction with the corpus cavernosa to facilitate sexual function.

9. The scrotum is a sac-like structure located behind the penis. It contains the testicles (testes), which are the primary male reproductive organs responsible for producing sperm and testosterone. The scrotum helps regulate the temperature of the testicles, keeping them slightly cooler than the body's core temperature. This temperature regulation is crucial for maintaining proper sperm development and function. Scrotum

10. The internal genital organs of the male reproductive system include the testes (singular: testis), epididymis, vas deferens ( ductus deferens), ejaculatory ducts, seminal vesicles, prostate gland, and bulbourethral glands. These structures are responsible for producing, storing, and delivering sperm and other components of semen. Internal Genital organs

11. Testes (Testicles): The testes are the primary male reproductive organs responsible for producing sperm and testosterone. Sperm are produced within the seminiferous tubules found in the testes. Epididymis: The epididymis is a coiled tube located on the surface of each testis. It serves as a storage and maturation site for sperm . Sperm produced in the testes mature and gain the ability to swim and fertilize an egg as they pass through the epididymis.

12. Vas Deferens (Ductus Deferens): The vas deferens is a muscular tube that transports mature sperm from the epididymis to the ejaculatory ducts . It travels through the spermatic cord and eventually joins with the duct of the seminal vesicle to form the ejaculatory duct.

13. Ejaculatory Ducts: The ejaculatory ducts are short tubes formed by the junction of the vas deferens and the duct of the seminal vesicle. They pass through the prostate gland and empty into the urethra within the prostate

14. Seminal Vesicles: The seminal vesicles are pouch-like structures located near the base of the bladder . They produce a significant portion of the fluid that makes up semen . This fluid contains fructose (a sugar that provides energy to sperm) and various proteins.

15. Prostate Gland: The prostate gland is a walnut-sized gland situated just below the bladder and surrounds the urethra. It produces a milky fluid that constitutes a significant portion of semen . This fluid contains enzymes, citric acid (provides energy to sperm), and substances that help activate sperm.

16. Bulbourethral Glands (Cowper's Glands): The bulbourethral glands are small pea-sized glands located beneath the prostate gland. They produce a clear, slippery fluid that is released before ejaculation. This fluid helps lubricate the urethra and neutralize any acidic urine remnants, creating a favorable environment for sperm. Collectively, these internal genital organs work together to produce, store, and deliver sperm and seminal fluid during ejaculation.

17. Anatomy of Spermatozoa Each sperm is an intricate motile cell, rich in DNA, with a head comprised mostly of chromosomal material. Approximately 60 μm long and 1 μm wide. Each sperm is composed: 1) Head that contains: Nucleus and densely packed chromosomes 2) Middle piece that contains Mitochondria that produce the ATP needed to move the tail 3) Tail : The only cell with flagellum in the human body which enables the spermatozoa to swim

18. Head: The head is the anterior (front) portion of the spermatozoa and contains the genetic material necessary for fertilization. Nucleus: The head contains a condensed nucleus with the haploid set of chromosomes (23 chromosomes in humans). Acrosome: The acrosome is a cap-like structure covering the anterior part of the nucleus. It contains enzymes that are released during the acrosome reaction , which helps the sperm penetrate the protective layers of the egg.

19. Midpiece (Neck): The midpiece is a narrow region located between the head and the tail. Mitochondria: The midpiece contains a high concentration of mitochondria, which produce energy (in the form of adenosine triphosphate or ATP) required for the sperm's movement. Tail (Flagellum): The tail is a long, whip-like structure that propels the sperm forward. Axoneme: The core of the tail contains microtubules organized in a 9+2 arrangement, forming the axoneme. This structure is responsible for the beating movement of the tail, allowing the sperm to swim in a characteristic whip-like motion.

20. Cells of seminiferous tubule The seminiferous tubules are the intricate structures found within the testes where sperm production, known as spermatogenesis, takes place. These tubules are composed of several types of cells that work together to produce and support the development of spermatozoa (sperm cells).

21. Spermatogonia: These are the stem cells located along the periphery of the seminiferous tubules . They undergo mitotic divisions to produce spermatocytes , which then undergo meiosis to form spermatids. Sertoli Cells: These are large, supportive cells that extend from the periphery to the lumen of the seminiferous tubules. They provide physical support, nourishment, and protection to developing sperm cells. Sertoli cells also create a blood-testis barrier, which prevents immune cells from attacking developing sperm.

22. Spermatocytes: These are the cells resulting from the mitotic division of spermatogonia. Primary spermatocytes undergo meiosis I to produce secondary spermatocytes. Spermatids: These are the immediate precursors to mature spermatozoa (Mature Sperm cells ) They undergo a process called spermiogenesis, during which they transform into mature sperm cells. Mature Spermatozoa: These are the fully developed, motile sperm cells that are released into the lumen of the seminiferous tubules. They will eventually travel through the male reproductive system to be ejaculated during sexual intercourse.

23. Hypothalamus-Pituitary-Testes axis – Male RS & Hormonal Control The hypothalamic-pituitary- gonadal axis is a key regulatory system that governs the hormonal control of the male reproductive system. It involves the release of GnRH from the hypothalamus , which stimulates the anterior pituitary to release LH and FSH. LH acts on Leydig cells to promote testosterone secretion , while FSH acts on Sertoli cells to support sperm development.

24. Hormones Secreted Functions Gonadotropin-Releasing Hormone (GnRH) Produced by the hypothalamus Stimulates the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland . Luteinizing Hormone (LH) Produced by the anterior pituitary gland Acts on Leydig cells in the testes . Stimulates the production and secretion of testosterone by Leydig cells Follicle-Stimulating Hormone (FSH) Produced by the anterior pituitary gland. Acts on Sertoli cells in the seminiferous tubules of the testes Stimulates spermatogenesis and supports the growth and maturation of sperm cells

25. Hormones Secreted Functions Testosterone Produced by Leydig cells in the testes. Regulates various aspects of male reproductive function, including the development of male secondary sexual characteristics (e.g., facial hair, deep voice), sperm production, and sex drive. Inhibin Produced by Sertoli cells in the testes Inhibin inhibits the secretion of follicle-stimulating hormone (FSH) from the pituitary gland. Prolactin Produced by the anterior pituitary gland Prolactin levels increase after ejaculation, leading to a temporary refractory period during which it's harder to achieve another erection and ejaculation

26. How Sperm travels ? Testes: Sperm are produced in the seminiferous tubules within the testes. Epididymis: Newly produced sperm move to the epididymis for maturation and development. Vas Deferens: Mature sperm travel through the vas deferens, a muscular tube. Ejaculatory Ducts: Vas deferens joins with seminal fluid-producing structures to form ejaculatory ducts. Ejaculation: Sperm and seminal fluid move through the urethra and out of the penis during ejaculation.