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the (334), and (89), male (55), system (44), are (36), from (34), #reproductive (32), edit (27), sex (26), genitalia (24), #external (23), testes (23), chromosome (20), development (20), human (19), organs (18), female (17), that (17), this (16), with (16), testis (16), penis (15), cells (15), scrotum (14), internal (13), during (13), main (13), glands (12), article (12), embryonic (12), into (12), sperm (12), ducts (11), testosterone (11), sexual (10), which (10), wikipedia (9), scrotal (9), arteries (9), duct (9), accessory (9), pmid (9), epididymis (9), weeks (9), will (9), structures (9), retrieved (8), other (8), nerves (8), van (8), graaff (8), fox (8), 1989 (8), differentiation (8), syndrome (8), urogenital (8), gonads (8), week (8), view (7), anatomy (7), fascia (7), urethral (7), seminal (7), gland (7), secondary (7), isbn (7), doi (7), archived (7), these (7), within (7), secretion (7), called (7), not (7), puberty (7), genital (7), toggle (6), veins (6), spermatic (6), body 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Text of the page (random words):
зча lëtzebuergesch lingua franca nova lietuvių malagasy मराठी bahasa melayu नेपाली oromoo polski português română русский srpskohrvatski српскохрватски සිංහල simple english slovenčina shqip svenska தமிழ் తెలుగు тоҷикӣ tagalog türkçe українська vèneto tiếng việt 粵語 中文 edit links article talk english read edit view history tools tools move to sidebar hide actions read edit view history general what links here related changes upload file permanent link page information cite this page get shortened url switch to legacy parser print export download as pdf printable version in other projects wikimedia commons wikidata item appearance move to sidebar hide from wikipedia the free encyclopedia reproductive system of the human male this article is about the human male reproductive system for the human female reproductive system see female reproductive system for the male reproductive systems of other organisms see reproductive system male reproductive system human male reproductive system details identifiers latin systema genitale masculinum mesh d005837 ta98 a09 0 00 002 ta2 3574 fma 45664 anatomical terminology edit on wikidata the male reproductive system consists of a number of sex organs that play a role in the process of human reproduction these organs are located on the outside of the body and within the pelvis the main male sex organs are the penis and the scrotum which contains the testicles that produce semen and sperm which as part of sexual intercourse fertilize an ovum in the female s body the fertilized ovum zygote develops into a fetus which is later born as an infant the corresponding system in females is the female reproductive system external genitalia edit a frontal view of an adult male showing the anatomical location of the external genitalia penis and scrotum in the pubic region penis edit main article human penis the penis is an intromittent organ with a long shaft an enlarged bulbous shaped tip called the glans and its foreskin for protection inside the penis is the urethra which is used to ejaculate semen and to excrete urine both substances exit through the meatus when a male becomes sexually aroused erection occurs because sinuses within the erectile tissues of the penis corpora cavernosa and corpus spongiosum become filled with blood the arteries of the penis are dilated while the veins are compressed so that blood flows into the erectile cartilage under pressure the penis is supplied by the pudendal artery scrotum edit main article scrotum the scrotum is a sac of skin that hangs behind the penis it holds and protects the testicles it also contains numerous nerves and blood vessels during times of lower temperatures the cremaster muscle contracts and pulls the scrotum closer to the body while the dartos fascia gives it a wrinkled appearance when the temperature increases the cremaster and dartos fascia relax to bring down the scrotum away from the body and remove the wrinkles respectively the scrotum remains connected with the abdomen or pelvic cavity through the inguinal canal the spermatic cord formed from spermatic artery vein and nerve bound together with connective tissue passes into the testis through inguinal canal internal genitalia edit labelled illustration of human internal male genitalia image showing innervation and blood supply of the human external male genitalia muscles of the external male genitalia and perineum testicles edit main article testicle the testicles are two gonads that produce sperm by meiotic division of germ cells within the seminiferous tubules 1 and synthesize and secrete androgens that regulate the male reproductive functions the site of production of androgens is the leydig cells that are located in the interstitium between seminiferous tubules 1 epididymides edit main article epididymis the epididymis is a long whitish mass of tightly coiled tube the sperm that are produced in the seminiferous tubules flow into the epididymis during passage via the epididymis the sperm undergo maturation and are concentrated by the action of ion channels located on the apical membrane of the epididymis 2 vasa deferentia edit main article vas deferens the vas deferens which is also known as the sperm duct is a thin tube approximately 30 centimetres 0 98 ft long that starts from the epididymis to the pelvic cavity it carries the sperm formally known as spermatozoa from the epididymis to the ejaculatory duct accessory glands edit main article male accessory gland three accessory glands provide fluids that lubricate the duct system and nourish the sperm cells seminal vesicles two glands behind the bladder that secrete many of the semen s components prostate gland a gland located below the bladder that produces seminal fluid and helps regulate urine flow bulbourethral glands add fluid to semen during ejaculation pre ejaculate development edit the embryonic and prenatal development of the male reproductive system is the process whereby the reproductive organs grow mature and are established it begins with a single fertilized egg and culminates 38 weeks later with the birth of a male child it is a part of the stages of sexual differentiation the development of the male reproductive system coincides with the urinary system their development can also be described together as the development of the urinary and reproductive organs sexual determination edit human karyotype showing 22 homologous autosomal chromosome pairs both the female xx and male xy versions of the two sex chromosomes as well as the mitochondrial genome at bottom left further information karyotype sexual identity is determined at fertilization when the genetic sex of the zygote has been initialized by a sperm cell containing either an x or y chromosome if this sperm cell contains an x chromosome it will coincide with the x chromosome of the ovum and a female child will develop a sperm cell carrying a y chromosome results in an xy combination and a male child will develop 3 genetic sex determines whether the gonads will be testes or ovaries in the developing embryo if the testes are developed it will produce and secrete male sex hormones during late embryonic development and cause the secondary sex organs of the male to develop 4 other embryonic reproductive structures edit the structures are masculinized by secretions of the testes urogenital sinus 5 genital tubercle urogenital folds cloacal membrane labioscrotal folds 6 the prostate gland derives from the urogenital sinus and the other embryonic structures differentiate into the external genitalia in the absence of testicular secretions the female genitalia are formed 7 external structures edit at six weeks post conception the differentiation of the external genitalia in the male and female has not taken place at eight weeks a distinct phallus is present during the indifferent stage by the 10th 12th week the genitalia are distinctly male or female being and derived from their homologous structures at 16 weeks post conception the genitalia are formed and distinct 8 9 the masculinization of the embryonic reproductive structures occurs as a result of testosterone secreted by the embryonic testes testosterone however is not the active agent within these organs once inside the target cells testosterone is converted by means of an enzyme called 5α reductase into the dihydrotestosterone dht dht mediates the androgen effect in these organs 10 testes edit main articles development of the gonads paramesonephric duct and mesonephric duct at nine weeks male differentiation of the gonads and the testes is well underway internal changes include the formation of the tubular seminar chris tubules in the rete testis from the primary sex cord developing on the outside surface of each testis is a phibro muscular cord called the gubernaculum this structure attaches to the inferior portion of the testis and extends to the labial sacral fold of the same side at the same time a portion of the embryonic mesonephric duct adjacent to the testis becomes attached and convoluted informs the epididymis another portion of the mesonephric duct becomes the ductus deferens 10 the seminal vesicles form from lateral outgrowths of the caudal and of each mesonephric duct the prostate gland arises from an indo dermal outgrowth of the urogenital sinus the bulbourethral glands develop from outgrowths in the membrane like portion of the urethra 10 the descent of the testes to its final location at the anterior abdominal wall followed by the development of the gubernaculum which subsequently pulls and translocates the testis down into the developing scrotum ultimately the passageway closes behind the testis a failure in this process can cause indirect inguinal hernia or an infantile hydrocoele 11 the testes descend into the scrotal sac between the sixth and 10th week descent does not occur until about the 28th week when compared to when canals form and the abdominal wall provides openings from the pelvic cavity to the scrotal sac the process by which a testis descends is not well understood but it seems to be associated with the shortening of the gubernaculum this is attached to the testis and extends through the inguinal canal to the wall of the scrotum as a testis it carries with it the ductus deference which are testicular vessels and nerves a portion of the abdominal muscle and lymph vessels all of the structures remain attached to the testis and form what is known as the spermatic cord by the time the testis is in the scrotal sac the gubernaculum is no more than a remnant of scar like tissue 10 male germ cells formed in the testes are capable of special dna repair processes that function during meiosis to repair dna damages and to maintain the integrity of the genomes that are to be passed on to progeny 12 these dna repair processes include homologous recombinational repair and non homologous end joining 12 external genitalia edit the external genitalia of the male is distinct from those of the female by the end of the ninth week prior to that the genital tubercle in both sexes is a phallus the urethral groove forms on the ventral surface of the phallus early in development during the differentiation of the external genitalia this is caused by the androgens produced and secreted by the testes androgen induced development causes the elongation and differentiation of the phallus into a penis a fusion of the urogenital folds surrounding the urethral groove along the ventral surface of the penis and a midline closure of the labioscrotal folds this closure forms the wall of the scrotum the external genitalia the external genitalia are completely formed by the end of the 12th week 10 13 at birth the development of the prepubertal male reproductive system is completed during the second trimester of pregnancy testosterone secretion in the male declines so that at birth the testes are inactive 14 gonadotropin secretion is low until the beginning of puberty 15 summary edit chart of the generalized male reproductive system embryionic the genetic sex is determined by whether a y bearing or x bearing sperm fertilizes the ovum the presence or absence of a y chromosome in turn determines whether the gonads of the embryo will be testes or ovaries and the presence or absence of testes finally determines whether the sex accessory organs and external genitalia will be male or female this sequence is understandable in light of the fact that both male and female embryos develop within the maternal environment high in estrogen secreted by the mother s ovaries and the placenta if estrogen determined the sex all embryos would become feminized 10 puberty edit main article puberty during puberty increased gonadotropin secretion stimulates a rise in sex steroids creation from the testes the increased secretion of testosterone from the testes during puberty causes the male secondary sexual characteristics to be manifested 16 male secondary sex characteristics include growth of body hair including underarm abdominal chest hair and pubic hair 17 18 growth of facial hair 18 enlargement of larynx adam s apple and deepening of voice 18 19 increased stature adult males are taller than adult females on average 18 heavier skull and bone structure 18 increased muscle mass and strength 18 broadening of shoulders and chest shoulders wider than hips 20 increased secretions of oil and sweat glands 19 secondary development includes the increased activity of the eccrine sweat glands and sebaceous glands along with the darkening of the skin in the scrotal region 15 clinical significance edit see also male genital disease chromosomal abnormalities edit sex chromosomes in xo sex determination main article chromosome abnormality ychromshowingsry2 chromosomal abnormalities can occur during fertilization impacting the development of the male reproductive system the genotype of the male consists of a y chromosome paired with an x chromosome female sex is determined by the absence of a y chromosome some individuals are male who have the xx male syndrome and androgen insensitivity syndrome this occurs when one x chromosome contains a segment of the y chromosome which was inserted into the x chromosome of the father s sperm rarely females are born with the xy genotype they are found to be missing the same portion of the y chromosome as was inserted into the chromosome of xx males the gene for sexual differentiation in humans called the testis determining factor tdf 21 non primary source needed is located on the short arm of the y chromosome 22 23 the presence or absence of the y chromosome determines whether the embryo will have testes or ovaries an abnormal number of sex chromosomes aneuploidy can occur this includes turner s syndrome a single x chromosome is present 24 klinefelter s syndrome two x chromosomes and a y chromosome are present xyy syndrome and xxyy syndrome other less common chromosomal arrangements include triple x syndrome 48 xxxx and 49 xxxxx 25 4 a diagram of the primitive urogenital organs from diagrams to show the development of male and female generative organs from a common type w w right and left wolffian ducts the observable visual differences become apparent between male or the female reproductive organs are not seen initially maturation continues as the medial aspect of each mesonephros grows to form the genital ridge the genital ridge continues to grow behind the developing peritoneal membrane by week six string like cell congregations called primitive sex cords form within the enlarging genital ridge externally a swelling called the genital tubercle appears above the cloacal membrane 4 the mesoderm extends to the midventral line external distinctions are not observed even by the eighth week of pre embryonic development this is the indifferent stage during which the gonads are relatively large and have an outer cortex of primitive sex cords and an inner medulla 4 specialized primordial germ cells are forming and migrating from ...
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