Male reproductive system

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Male reproductive system

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Male reproductive system

  1. 1. ll Male reproductive systemMale reproductive system The male reproductive system is composed ofThe male reproductive system is composed of A)A) The testes (Male gonads):The testes (Male gonads): The testes are theThe testes are the primary sex organsprimary sex organs in males .theyin males .they have two functions :have two functions : Exocrine function (Spermatogenesis) spermExocrine function (Spermatogenesis) sperm formationformation .. Endocrine function:Endocrine function: secretion of hormones:secretion of hormones: Testosterone ,the principle male sex hormone .Testosterone ,the principle male sex hormone . Inhibin & estrogen refer to spermatogenesis .Inhibin & estrogen refer to spermatogenesis . TheThe secondary (Accessory ) sex organssecondary (Accessory ) sex organs:: 1- Epididymis1- Epididymis: a single coiled tube in which sperms: a single coiled tube in which sperms are stored continue their maturation ,become motile andare stored continue their maturation ,become motile and acquire the power of fertilization .acquire the power of fertilization . 2-2- vas deferencs:vas deferencs: a long duct which store &a long duct which store & Transports sperms from the tail of the epididymis to theTransports sperms from the tail of the epididymis to the ejaculatory ducts.ejaculatory ducts. 3- Seminal vesicle3- Seminal vesicle: One on each side of the prostate: One on each side of the prostate .. Act as a gland .it does not secret sperms ,secretAct as a gland .it does not secret sperms ,secret mucoid viscid fluid rich in fructose ,prostaglandinmucoid viscid fluid rich in fructose ,prostaglandin ,fibrinogen and ascorbic acids,fibrinogen and ascorbic acids Fructose a nutrient for ejaculated spermsFructose a nutrient for ejaculated sperms Prostaglandins aid fertilization by causing reverseProstaglandins aid fertilization by causing reverse peristalsis in the uterus & fallopian tubeperistalsis in the uterus & fallopian tube
  2. 2. 4-4- Prostate glandsProstate glands secrete alkaline milky fluid to neutralize the acidity ofsecrete alkaline milky fluid to neutralize the acidity of vagina and male urethra ,vagina and male urethra , 5-Bubo urethral glands (Cowper's glands):5-Bubo urethral glands (Cowper's glands): secrete mucus which is discharged into the penilesecrete mucus which is discharged into the penile urethra during excitements .urethra during excitements . The testesThe testes The testes consists of :The testes consists of : a-a- seminiferous tubulesseminiferous tubules: lined with 2 type of: lined with 2 type of cells :cells : - Spermatogonia : form the sperm .- Spermatogonia : form the sperm . Sertoli cells : are large cells that extend from theSertoli cells : are large cells that extend from the basement membrane of the seminiferous tubule tobasement membrane of the seminiferous tubule to the lumen and envelop the developing germ cellsthe lumen and envelop the developing germ cells b-b- Interstitial cell of leygigInterstitial cell of leygig ; secrete the male; secrete the male sex hormone testosterone .sex hormone testosterone . Functions of the testesFunctions of the testes SpermatogenesisSpermatogenesis Is the formation of the spermatozoa from theIs the formation of the spermatozoa from the primitive germ cells (spermatogonia ) .This takesprimitive germ cells (spermatogonia ) .This takes 7474 days to form a mature sperm.days to form a mature sperm. Spermatogenesis begins at puberty and continuesSpermatogenesis begins at puberty and continues throughout life .throughout life .
  3. 3. Stages of spermatogenesisStages of spermatogenesis:: Spermatogenesis is divided into 3 stages:Spermatogenesis is divided into 3 stages: 1- spermatocytogenesis1- spermatocytogenesis Formation of primary spermatocyte from spermatogonia( 4mitotic divisionFormation of primary spermatocyte from spermatogonia( 4mitotic division )) 2- Meiosis (reduction divipsion )2- Meiosis (reduction divipsion ) Primary spermatocyte is converted into secondary by the process ofPrimary spermatocyte is converted into secondary by the process of meiosismeiosis 3- spermiogenesis3- spermiogenesis Maturation of spermatid to form sperm . It occure in cytoplasmic foldMaturation of spermatid to form sperm . It occure in cytoplasmic fold of sertoli cellof sertoli cell Factor affecting spermatogenesisFactor affecting spermatogenesis Hormonal factorHormonal factor (Anterior pituitary hormones)(Anterior pituitary hormones) Pituitary gonadotropinPituitary gonadotropin Follicular stimulating hormone (FSH)Follicular stimulating hormone (FSH) It stimulate gametogenic function of the testes ,it stimulate growth &It stimulate gametogenic function of the testes ,it stimulate growth & secretion of setoli cells ,this results insecretion of setoli cells ,this results in Conversion of spermatids into sperm (spermiogenesis )Conversion of spermatids into sperm (spermiogenesis ) Lutenizing hormone (LH = ICSH)Lutenizing hormone (LH = ICSH) Stimulate testosterone secretion by leydig cells ,increased number ofStimulate testosterone secretion by leydig cells ,increased number of interstitial cell of leydig.interstitial cell of leydig. 2- testosterone ; required for complete meiotic division of primary2- testosterone ; required for complete meiotic division of primary spermatocyte to form secondary spermatocyte, then finally maturationspermatocyte to form secondary spermatocyte, then finally maturation of spermatid to form sperm.of spermatid to form sperm. PROLACTIN & growth hormonePROLACTIN & growth hormone : its role is not known.: its role is not known.
  4. 4. Other hormonesOther hormones TestosteroneTestosterone ;; Complete meiotic division of primary spermatocyte to form secondary spermatocyte.Complete meiotic division of primary spermatocyte to form secondary spermatocyte. Maturation of spermatid to form sperm.Maturation of spermatid to form sperm. Oestrogen;Oestrogen; Decrease FSH secretion so inhibit spermatogenesis.Decrease FSH secretion so inhibit spermatogenesis. Thyroxin;Thyroxin; Increase metabolisim so stimulate spermatogenesis.Increase metabolisim so stimulate spermatogenesis. InhibinInhibin : inhibit FSH by direct effect on the anterior pituitary this negative feed back: inhibit FSH by direct effect on the anterior pituitary this negative feed back mechanism control spermatogenesis.mechanism control spermatogenesis. ActivinActivin ; Formed from inhibin precursor .Activin stimulate FSH secretion; Formed from inhibin precursor .Activin stimulate FSH secretion DietDiet Abalanced diet containing adequate amount of proteins and vitamins (A,B,C,E)Abalanced diet containing adequate amount of proteins and vitamins (A,B,C,E) Starvation;Starvation; decrease FSH&LH so arrest spermatogenesisdecrease FSH&LH so arrest spermatogenesis Protein defficiency;Protein defficiency; arrest spermatogenesisarrest spermatogenesis Vitamin E deficiencyVitamin E deficiency ;in rate lead to tubular degeneration but not proved in man .;in rate lead to tubular degeneration but not proved in man . Vitamin B Complex;Vitamin B Complex; need in metabolic activity in general but not specific forneed in metabolic activity in general but not specific for spermatogenesis .spermatogenesis . Vitamin B 12;Vitamin B 12; Stimulate nuclic acid synthesis ,need for spermatogenesisStimulate nuclic acid synthesis ,need for spermatogenesis
  5. 5. TemperatureTemperature The optimum temperature for spermatogenesis is 35 it is kept at theseThe optimum temperature for spermatogenesis is 35 it is kept at these temperature due to scrotal skin is thin ,rich in sweat glands and contain littletemperature due to scrotal skin is thin ,rich in sweat glands and contain little subcutaneous fat.subcutaneous fat. Also in cold weather reflex contraction of scrotal muscle to pull the testesAlso in cold weather reflex contraction of scrotal muscle to pull the testes close to the body ,but in hot weather relaxation of dartos muscleclose to the body ,but in hot weather relaxation of dartos muscle Cryptorchidism (Undescended testes)Cryptorchidism (Undescended testes) Failure of the testes to descend from the abdomen to scrotum causeFailure of the testes to descend from the abdomen to scrotum cause degeneration of tubular epithelium and sterility .spermatogenesis fails butdegeneration of tubular epithelium and sterility .spermatogenesis fails but testosterone secretion continuestestosterone secretion continues Fever or hot baths for 30 minutes reduce the sperm count in males.Fever or hot baths for 30 minutes reduce the sperm count in males. IrradiationIrradiation Atomic radiation and large doses of x –rays cause irreversable damage ofAtomic radiation and large doses of x –rays cause irreversable damage of germinal epitheliumgerminal epithelium Other factorsOther factors O2 lack ,bacterial toxins and chemical toxins depress spermatogenesis .O2 lack ,bacterial toxins and chemical toxins depress spermatogenesis .
  6. 6. Sertoli cellsSertoli cells Sertoli cells are large cells that extend from the basement membrane of theSertoli cells are large cells that extend from the basement membrane of the seminiferous tubule to the lumen of the tubuleseminiferous tubule to the lumen of the tubule Function of sertoli cells:Function of sertoli cells: 1- Nurse cells1- Nurse cells; Sertoli cells are called nurse cells because they support and nourish spermatocytes; Sertoli cells are called nurse cells because they support and nourish spermatocytes ,spermatids and spermatozoa ,due to their high glycogen content .,spermatids and spermatozoa ,due to their high glycogen content . 22--spermiationspermiation ; Release of mature sperms from the setoli cells to become free in the tubular lumen.under; Release of mature sperms from the setoli cells to become free in the tubular lumen.under the controlled of LHthe controlled of LH.. 3-Secretion3-Secretion : FSH stimulate setoli cells to secrete ;: FSH stimulate setoli cells to secrete ; aa) Androgen binding protein) Androgen binding protein (ABP);(ABP); act as a carrier of testosterone from tests to epididymis.act as a carrier of testosterone from tests to epididymis. B)B) Mullerian inhibiting substanceMullerian inhibiting substance : it cause of regression of mullerian ducts in male during fetal life .: it cause of regression of mullerian ducts in male during fetal life . CC) Inhibin) Inhibin;; inhibit FSH by direct feed back effects from hypothalamus .inhibit FSH by direct feed back effects from hypothalamus . DD) Estrogen.) Estrogen. 4- Blood – testes Barrier4- Blood – testes Barrier :: IS a memberane formed by the tight junction between theIS a memberane formed by the tight junction between the basis of setoli cellsbasis of setoli cells .Functions;.Functions; A) protect germ cells from injurious substance in the blood ( circulating immunoglobulin's that may affectA) protect germ cells from injurious substance in the blood ( circulating immunoglobulin's that may affect spermatogenesisspermatogenesis B) prevents antigenic prouct of germ cell division from entering the circulation .B) prevents antigenic prouct of germ cell division from entering the circulation . 5- contain aromatse enzymes5- contain aromatse enzymes responsible for conversion of androgens to estrogens .responsible for conversion of androgens to estrogens . 6- receptors for FSH6- receptors for FSH are present only in setoli cells .are present only in setoli cells .
  7. 7. SpermatozoaSpermatozoa Each sperm is motile cell composed of a head,Each sperm is motile cell composed of a head, body and tailbody and tail 1- The head :1- The head : consists of nucleus formedconsists of nucleus formed of chromosomal material (DNA), thenof chromosomal material (DNA), then cytoplasm and cell membrane .cytoplasm and cell membrane . Acrosome : Thick cap that covers theAcrosome : Thick cap that covers the anterior 2/3 of the head ,formed mainly fromanterior 2/3 of the head ,formed mainly from the golgi apparatus .Acrosome contain manythe golgi apparatus .Acrosome contain many enzymes including hyaluronidase andenzymes including hyaluronidase and protolytic enzymes that help the sperm toprotolytic enzymes that help the sperm to penetrate the fertilized ovum .penetrate the fertilized ovum . 2-The body2-The body : collection of mitochondria: collection of mitochondria surrounding the proximal part of the tail .surrounding the proximal part of the tail . 3-The tail (Flagellum):3-The tail (Flagellum): The motility ofThe motility of the sperm is produced by movement of itsthe sperm is produced by movement of its tail. ATP synthesized by the mitochondriatail. ATP synthesized by the mitochondria supplies the energy required for flagellarsupplies the energy required for flagellar movement.movement. Capacitation of theCapacitation of the spermatozoa :spermatozoa : Contact of sperm with fluids in the femaleContact of sperm with fluids in the female genital tract from 1-10 hoursgenital tract from 1-10 hours
  8. 8. TestosteroneTestosterone The tests secrete several male sex hormones ,which collectively calledThe tests secrete several male sex hormones ,which collectively called AndrogensAndrogens ,including,including;; 1- testosterone ,more abundant1- testosterone ,more abundant 2- Dihydrotestosterone2- Dihydrotestosterone 3- Andrstenedione3- Andrstenedione Testosterone is formed by the interstitial cells of leydige .it is a steroid hormoneTestosterone is formed by the interstitial cells of leydige .it is a steroid hormone Transport of testosteroneTransport of testosterone 65% of testosterone is bound to beta globulin called gonadal steroid binding65% of testosterone is bound to beta globulin called gonadal steroid binding globulin = GBGglobulin = GBG 33% Loosely bound to albumin .33% Loosely bound to albumin . Actions of testosterone :Actions of testosterone : 1)1) Primary sex organs (TESTS);Primary sex organs (TESTS); Testosterone and FSH are important for spermatogenesisTestosterone and FSH are important for spermatogenesis 2)Secondary sex organs;2)Secondary sex organs; It is essential for development ,growth and maintenance of male secondaryIt is essential for development ,growth and maintenance of male secondary sex organs i.e epididymis, vas deference ,seminal vesicle ,prostate,sex organs i.e epididymis, vas deference ,seminal vesicle ,prostate, bulbouretheral glands ,penis and scrotumbulbouretheral glands ,penis and scrotum ..
  9. 9. Secondary sex charactersSecondary sex characters;; A) hairA) hair ;; Body hair is increased but scalp hair is decreased ,hair appearBody hair is increased but scalp hair is decreased ,hair appear on theon the face,face, on the chest , axilla and over the pubis .hereditary baldness appear . Pubicon the chest , axilla and over the pubis .hereditary baldness appear . Pubic hair is triangular toward the umbilicus.hair is triangular toward the umbilicus. B) skinB) skin :is thickened with excessive thick secretion of sebaceous glands:is thickened with excessive thick secretion of sebaceous glands C)Voice ;C)Voice ; Larynx enlarge .vocal cord increase in length and thickness ,voiceLarynx enlarge .vocal cord increase in length and thickness ,voice become deeper and lower in pitchbecome deeper and lower in pitch D)Body configrationD)Body configration ; Shoulder broaden and muscles enlarge .; Shoulder broaden and muscles enlarge . E) Behaviour changesE) Behaviour changes : increased libido (Sexual desire ) and male become: increased libido (Sexual desire ) and male become aggressive .aggressive . General metabolic effects ;General metabolic effects ; Testosterone has protein anabolic effects; Increase protein formation in the targetTestosterone has protein anabolic effects; Increase protein formation in the target sex organs ,muscle & bones. This increase ; muscle bulk ,formation of bone matrixsex organs ,muscle & bones. This increase ; muscle bulk ,formation of bone matrix and deposition of calcium salts therefore testosterone is used for the treatment ofand deposition of calcium salts therefore testosterone is used for the treatment of osteoporosis in old age .osteoporosis in old age . Secondary to anabolic actionSecondary to anabolic action ;; TESTOSTERONE LEADS TO ;TESTOSTERONE LEADS TO ; Increased rate of growth (Increased rate of growth (GROWTH SPURTS )GROWTH SPURTS ) at a time of puberty but androgensat a time of puberty but androgens terminate growth by causing epiphysial closureterminate growth by causing epiphysial closure Increased Basal metabolic rate .Increased Basal metabolic rate . Increase red blood cell count .Increase red blood cell count .
  10. 10. CONTROL OF TESTOSTERONE SECRETIONCONTROL OF TESTOSTERONE SECRETION Testosterone secretion is controlled by LHTestosterone secretion is controlled by LH (ICSH) secreted by the basophile(ICSH) secreted by the basophile gonadotrophin of the anterior pituitarygonadotrophin of the anterior pituitary Control of LH secretion ;Control of LH secretion ; 1)1) GONADOTROPHIN –RELEASINGGONADOTROPHIN –RELEASING HORMONE (GNRH)HORMONE (GNRH) Secreted from the hypothalamus and transported toSecreted from the hypothalamus and transported to the anterior pituitary through hypothalamicthe anterior pituitary through hypothalamic hyperphyseal portal circulationhyperphyseal portal circulation Stimulate release of gonadotropin LH & FSHStimulate release of gonadotropin LH & FSH 2) testosterone level in plasma (feed back2) testosterone level in plasma (feed back control )control ) High testosterone level has adirect feed back effect onHigh testosterone level has adirect feed back effect on ; HYPOTHALAMUS; HYPOTHALAMUS TO DECREASE SECRETIONTO DECREASE SECRETION OF GNRHOF GNRH THE ANTERIOR PITUITARYTHE ANTERIOR PITUITARY ; to decrease secretion; to decrease secretion of LH .of LH . High testosterone levelHigh testosterone level lead to inhibit of GNRHlead to inhibit of GNRH secretion which inhibit FSH & LH Theirforesecretion which inhibit FSH & LH Theirfore injection of testosterone in male for several weeksinjection of testosterone in male for several weeks inhibit spermatogenesis .inhibit spermatogenesis . Low testosterone levelLow testosterone level ; Lack of negative feed back; Lack of negative feed back effects ,increased gonadotropin secretioneffects ,increased gonadotropin secretion increased FSH & LH .this occurs in primaryincreased FSH & LH .this occurs in primary hypogonadisimhypogonadisim .. ii
  11. 11. Abnormalities of testicular functionAbnormalities of testicular function Male hypogonadismMale hypogonadism Hypogonadism of the testes .2 typeHypogonadism of the testes .2 type Primary ;Primary ; due to testicular failure .gonadotrophin increased both in blood and urine .due to testicular failure .gonadotrophin increased both in blood and urine . Secondary ;Secondary ; due to failure of pituitary gonadotrophin secretion as in pituitary or hypothalamicdue to failure of pituitary gonadotrophin secretion as in pituitary or hypothalamic diseasedisease Bilateral castrationBilateral castration Castration means removal of the testesCastration means removal of the testes Pre puberal castration(before puberty)Pre puberal castration(before puberty) Permanent sterility due to absence of spermatozoa ,external & internal genital organs infantilePermanent sterility due to absence of spermatozoa ,external & internal genital organs infantile Male sex character don’t develop ,i.e no beard ,soft skin, feminine hair distribution ,weak muscleMale sex character don’t develop ,i.e no beard ,soft skin, feminine hair distribution ,weak muscle ,sharp voice,sharp voice Delays closure of epiphysis leading to overgrowth of long bone (span more than height).Delays closure of epiphysis leading to overgrowth of long bone (span more than height). Post puberal castration (after puberty)Post puberal castration (after puberty) Gradual decrease of sexual activityGradual decrease of sexual activity Gradual atrophy of internal genital organs as seminal vesicle prostate ,muscle wasting ,decreaseGradual atrophy of internal genital organs as seminal vesicle prostate ,muscle wasting ,decrease hair of facehair of face Sexual desire : is depressed ,erection ,ability to copulate is persist but without ejaculationSexual desire : is depressed ,erection ,ability to copulate is persist but without ejaculation Male climacteric ,Like female menopauseMale climacteric ,Like female menopause Occurring in old age they have hot flushes sweating nervousness, easy fatigueOccurring in old age they have hot flushes sweating nervousness, easy fatigue Increased gonadotropin (FSH& LH ) in urine .Increased gonadotropin (FSH& LH ) in urine . Male hypergonadismMale hypergonadism Hyperfunction of the testes rare to occursHyperfunction of the testes rare to occurs

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