1. Male Reproductive System spermatogenesis, which means simply the formation of sperm (2) regulation of male reproductive functions by the various hormones (3) performance of the male sexual act

2. MALE REPRODUCTIVE SYSTEM THE ORGANS AND THEIR FUNCTIONS:- SCROTUM:- TEMPERATURE REGULATION AND PROTECTION OF THE TESTES TESTES:- SPERMS PRODUCTION & THE SECRETION OF MALE SEX HORMONES DUCTS:- STORE & TRANSPORT SPERMS ACCESSORY GLANDS:- SECRETION OF THE FLUID PART OF THE SEMEN PENIS:- MALE ORGAN OF COPULATION

3. 3 MALE REPRODUCTIVE SYSTEM

4. The testis is composed of seminiferous tubules, in which the sperm are formed The sperm then empty into the epididymis The epididymis leads into the vas deferens Two seminal vesicles, one located on each side of the prostate, empty into the prostatic end of the ampulla, pass into an ejaculatory duct The urethra is the last connecting link from the testis to the exterior The urethra is supplied with mucus derived from urethral glandsand also from bilateralbulbourethral glands (Cowper's glands) located near the origin of the urethra Physiologic Anatomy of the Male Sexual Organs

5. 5 TESTES SEMINEFEROUS TUBULES INTERSTITIAL CELLS

6. Spermatogenesis Sequence of events by which spermatogonia are transformed into mature sperm orspermatozoa

7. Spermatogenesis Spermatogonia that cross the barrier into the Sertoli cell layer become progressively modified and enlarged to form large primary spermatocytes Each of these, in turn, undergoes meiotic division to form two secondary spermatocytes After another few days, these too divide to form spermatidsthat are eventually modified to become spermatozoa (sperm)

8. Spermatogenesis SPERMATOGENESIS: Occurs in the seminiferous tubules during active sexual life 1º SPERMATOCYTE 2º SPERMATOCYTE SPERMATIDS SPERMATOGONIA SPERMATIDS 2º SPERMATOCYTE 1º SPERMATOCYTE - The first stage is the spermatogonia migrate among Sertoli cells toward the central lumen of the seminiferous tubule SERTOLI CELLS: are large cells that surround the developing spermatogonia SERTOLI CELLS SPERMATOGONIA

9. The Seminiferous Tubules

10. Spermiogenesis The process by which thespermatidsalter their shape and differentiateinto sperm cellsisspermiogenesis

11. Spermatogenesis & Spermiogenesis Takes about 2 months(64-74 days) Everyday a healthy adult male produces about 400 million sperms Sperm are mostly stored in the vas deferens. They can remain stored, maintaining their fertility, for at least a month

12. Functions of Sertoli cells: 1)Tight junctions between Sertoli cells form blood-testes barrier which maintains critical composition of tubular fluid for sperm maturation 2) Secrete fluid for carrying sperm into the epididymis 3) Provide nutrients for maturing sperm 4) Secrete ABP (androgen-binding protein) that functions to maintain high levels of androgens in the tubular fluid 5) Contain aromatase which converts androgens to estrogens 6) Secrete inhibin

13. 13 THE SPERM

14. The anterior 2/3 of the head is covered by theacrosome Acrosome:cap at top of sperm head, contains hyaluronidase and proteolytic enzymes, important in penetration into ovum Mitochondria – arranged around body Tail, or flagellum, undergoes whip-like movements that propel the spermthrough the female reproductive tract Spermatozoa - head

15. Physiology of the Mature Sperm The activity of sperm is greatly enhanced in a neutral and slightly alkaline medium The activity of sperm increases with increasing temperature Life expectancy of ejaculated sperm in the female genital tract is only 1 to 2 days

16. Function of the Seminal Vesicles Secretes a mucoid material containing an abundance of fructose, citric acid, large quantities of prostaglandins and fibrinogen The fructose considerable nutrient value for the ejaculated sperm until one of the sperm fertilizes the ovum Prostaglandinsare important in fertilization

17. Function of the Prostate Gland Secretes a milky fluid that contains calcium, citrate ion, phosphate ion, a clotting enzyme, and a profibrinolysin A slightly alkaline characteristic of the prostatic fluid important for successful fertilization of the ovum

18. Semen Semen is composed of the fluid and sperm Sperm from the vas deferens resemble about 10 per cent of the total Fluid from the seminal vesicles (almost 60 per cent) Fluid from the prostate gland (about 30 per cent) Small amounts from the mucous glands, especially the bulbourethral glands The average pH= 7.5 Each ejaculation contains approximately 3.5 ml, about 120 million sperm/ml

19. Capacitation Freshly ejaculated sperm do not possess the capacity to fertilize ovum This capacity to fertilize is acquired in the female genital tract, and, appears to involve a reversal of inhibitory factors secreted by the epididymis

20. Acrosome Reaction Upon contact with the ovum, the acrosomal cap binds with the cell membrane of the ovum This allows release of digestive enzymes, which digest the cell membrane of the ovum allowing the sperm contents to enter

21. Hormonal Factors That Stimulate Spermatogenesis Testosterone: secreted by the Leydig cellsis essential for growth and division of the testicular germinal cells, which is the first stage in forming sperm Luteinizing hormone: secreted by the anterior pituitary gland, stimulates the Leydig cells to secrete testosterone Follicle-stimulating hormone: stimulates the Sertoli cells; which stimulate the conversion of the spermatids to sperm Estrogens: formed from testosterone by the Sertoli cells when they are stimulated by follicle-stimulating hormone Growth hormone: Growth hormone promotes early division of the spermatogonia themselves

22. Hormonal Feedback and the Regulation of the Male Reproductive Function

24. Testosterone Secretion and Other Male Sex Hormones The testes secrete several male sex hormones, which are collectively called androgens, including testosterone, dihydrotestosterone, and androstenedione. Testosterone is formed by the interstitial cells of Leydig Leydig cells are almost nonexistent in the testes during childhood Leydig cells numerous in the newborn male infant for the first few months of life and in the adult male any time after puberty

25. Different stages of male sexual functions: plasma testosterone and sperm production

26. Functions of Testosterone 1. fetal development:present at 2nd month of embryonic life presence or absence of testosterone determines development of genital organs and characteristics 2. causes descent of testes into scrotum during last 2-3 months of pregnancy

27. Functions of Testosterone adult primary and secondary characteristics: 1)body hair distribution (pubis, face, chest, back, etc) 2) voice: hypertrophy of laryngeal mucosa and larynx 3) skin: thickens skin and increases ruggedness of subcutaneous tissues, sebaceous glands and oil production 4) muscle development

28. Functions of Testosterone 5) bone growth and calcium retention: thought to inhibit production of osteoclasts 6) red blood cells – causes increases in erythropoeitin –stimulates RBC production 7) stimulates sodium and water reabsorption in DT of kidney

29. BODY OF PENIS IS MADE FROM THREE COLUMNS OF ERECTILE TISSUE:- TWO CORPORA CAVERNOSA ONE CORPUS SPONGIOSUM GLANS PENIS IS MADE BY EXPANSION OF THE CORPUS SPONGIOSUM. PREPUCE IS A SKIN SHEATH COVERING THE GLANS PENIS. PENIS

30. Male Sexual Response Erection: controlled by parasympathetic nervous system activity to penile arterioles = vasodilation of the arterioles and erection Parasympathetic release NO in addition to Ach - NO relaxes the arteries of the penis - relaxes the trabecular meshwork of smooth muscle fibre in the erectile tissue Of the corpora cavernosa and corpus spongiosum –veins are compressed causing reduction in venous return

31. Male Sexual Response Emission: movement of ejaculate into proximal part of urethra under sympathetic control – causes sequential peristaltic contraction of smooth muscle of vas deferens –closing of bladder sphincter Ejaculation: spinal reflex – triggered by entry of semen into urethra causes nerve impulses to activate perineal muscles – forcibly expel semen from urethra Orgasm: culmination of sexual excitation At its termination, the male sexual excitement disappears entirely Within 1 – 2 minutes

32. The Penis