The development of the reproductive system is the part of embryonic growth that results in the

sex organs A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, ...

and contributes to

sexual differentiation Sexual differentiation is the process of development of the sex differences between males and females from an undifferentiated zygote. Sex determination is often distinct from sex differentiation; sex determination is the designation for the dev ...

. Due to its large overlap with development of the urinary system, the two systems are typically described together as the urogenital or genitourinary system. The reproductive organs develop from the

intermediate mesoderm Intermediate mesoderm or intermediate mesenchyme is a narrow section of the mesoderm (one of the three primary germ layers) located between the paraxial mesoderm and the lateral plate of the developing embryo. The intermediate mesoderm develop ...

and are preceded by more primitive structures that are superseded before birth. These embryonic structures are the

mesonephric duct The mesonephric duct (also known as the Wolffian duct, archinephric duct, Leydig's duct or nephric duct) is a paired organ that forms during the embryonic development of humans and other mammals and gives rise to male reproductive organs. Stru ...

s (also known as ''Wolffian ducts'') and the

paramesonephric duct Paramesonephric ducts (or Müllerian ducts) are paired ducts of the embryo that run down the lateral sides of the genital ridge and terminate at the sinus tubercle in the primitive urogenital sinus. In the female, they will develop to form the f ...

s, (also known as ''Müllerian ducts''). The mesonephric duct gives rise to the male

seminal vesicles The seminal vesicles (also called vesicular glands, or seminal glands) are a pair of two convoluted tubular glands that lie behind the urinary bladder of some male mammals. They secrete fluid that partly composes the semen. The vesicles are 5� ...

, epididymes and

vas deferens The vas deferens or ductus deferens is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube ...

. The paramesonephric duct gives rise to the female fallopian tubes,

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...

, cervix, and upper part of the

vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...

Mesonephric ducts

The mesonephric duct originates from a part of the pronephric duct.

Origin

In the outer part of the

, immediately under the ectoderm, in the region from the fifth

cervical segment The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

to the third

thoracic segment The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

, a series of short

evagination Endodermic evagination relates to the inner germ layers of cells of the very early embryo, from which is formed the lining of the digestive tract, of other internal organs, and of certain glands, implies the extension of a layer of body tissue to ...

s from each segment grows

dorsally Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and extends

caudally Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

, fusing successively from before backward to form the pronephric duct. This continues to grow caudally until it opens into the ventral part of the cloaca; beyond the

pronephros Pronephros is the most basic of the three excretory organs that develop in vertebrates, corresponding to the first stage of kidney development. It is succeeded by the mesonephros, which in fish and amphibians remains as the adult kidney. In amnio ...

it is termed the mesonephric duct. Thus, the mesonephric duct remains after the atrophy of the pronephros duct.

Development in male

In the male the duct persists, and forms the tube of the epididymis, the

and the

ejaculatory duct The ejaculatory ducts (''ductus ejaculatorii'') are paired structures in male anatomy. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the ureth ...

, while the

seminal vesicle The seminal vesicles (also called vesicular glands, or seminal glands) are a pair of two convoluted tubular glands that lie behind the urinary bladder of some male mammals. They secrete fluid that partly composes the semen. The vesicles are 5� ...

arises during the third month as a lateral diverticulum from its hinder end. A large part of the head end of the mesonephros atrophies and disappears; of the remainder the anterior tubules form the efferent ducts of the

testicle A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...

; while the posterior tubules are represented by the

ductuli aberrantes Ductuli aberrantes are two long narrow tubes, the ductulus aberrans inferior and the ductulus aberrans superior. The ductulus aberrant inferior (vas aberrans of Haller), is occasionally found connected with the lower part of the canal of the epid ...

, and by the

paradidymis The term paradidymis (organ of Giraldés) is applied to a small collection of convoluted tubules, situated in front of the lower part of the spermatic cord, above the head of the epididymis. These tubes are lined with columnar ciliated epitheli ...

, which is sometimes found in front of the

spermatic cord The spermatic cord is the cord-like structure in males formed by the vas deferens (''ductus deferens'') and surrounding tissue that runs from the deep inguinal ring down to each testicle. Its serosal covering, the tunica vaginalis, is an exten ...

above the head of the epididymis.

Atrophy in female

In the female the mesonephric bodies and ducts atrophy. The nonfunctional remains of the

mesonephric tubule The mesonephros ( el, middle kidney) is one of three excretory organs that develop in vertebrates. It serves as the main excretory organ of aquatic vertebrates and as a temporary kidney in reptiles, birds, and mammals. The mesonephros is included ...

s are represented by the

epoophoron The epoophoron or epoöphoron (also called organ of RosenmüllerJ. C. Rosenmüller. De ovariis embryonum et foetuum humanorum. 1802. or the parovarium) is a remnant of the mesonephric tubules that can be found next to the ovary and fallopian tu ...

, and the paroöphoron, two small collections of rudimentary blind tubules which are situated in the

mesosalpinx The mesosalpinx is part of the lining of the abdominal cavity in higher vertebrates, specifically the portion of the broad ligament that stretches from the ovary to the level of the fallopian tube. See also * Mesometrium * Mesovarium The m ...

Remnants

The lower part of the mesonephric duct disappears, while the upper part persists as the longitudinal duct of the

epoöphoron The epoophoron or epoöphoron (also called organ of RosenmüllerJ. C. Rosenmüller. De ovariis embryonum et foetuum humanorum. 1802. or the parovarium) is a remnant of the mesonephric tubules that can be found next to the ovary and fallopian tu ...

, called

Gartner's duct Gartner's duct, also known as Gartner's canal or the ductus longitudinalis epoophori, is a potential embryological remnant in human female development of the mesonephric duct in the development of the urinary and reproductive organs. It was disco ...

. There are also developments of other tissues from the mesonephric duct that persist, e.g. the

development of the suspensory ligament of the ovary The suspensory ligament of the ovary, also infundibulopelvic ligament (commonly abbreviated IP ligament or simply IP), is a fold of peritoneum that extends out from the ovary to the wall of the pelvis. Some sources consider it a part of the broad ...

Paramesonephric ducts

Shortly after the formation of the mesonephric ducts a second pair of ducts is developed; these are the

s. Each arises on the lateral aspect of the corresponding mesonephric duct as a tubular invagination of the cells lining the abdominal cavity. The orifice of the invagination remains open, and undergoes enlargement and modification to form the distal tubal opening (abdominal ostium) of the fallopian tube. The ducts pass backward lateral to the mesonephric ducts, but toward the posterior end of the embryo they cross to the medial side of these ducts, and thus come to lie side by side between and behind the latter—the four ducts forming what is termed the ''common genital cord'', to distinguish it from the ''genital cords of the germinal epithelium'' seen later in this article. The mesonephric ducts end in an epithelial elevation, the

sinus tubercle Sinus tubercle (also known as sinual tubercle or Müllerian eminence) is the proliferation of endoderm induced by the paramesonephric ducts. It is located in the developing fetus between the orifices of the mesonephric ducts on the urogenital s ...

, on the ventral part of the cloaca between the orifices of the mesonephric ducts. At a later stage the sinus tubercle opens in the middle, connecting the paramesonephric ducts with the cloaca.

Atrophy in males

In the male the paramesonephric ducts atrophy (but traces of their anterior ends are represented by the appendix of testis of the male), while their terminal fused portions form the

prostatic utricle The prostatic utricle (Latin for "small pouch of the prostate") is a small indentation in the prostatic urethra, at the apex of the urethral crest, on the seminal colliculus (''verumontanum''), laterally flanked by openings of the ejaculatory duct ...

in the floor of the prostatic urethra. This is due to the production of

Anti-Müllerian hormone Anti-Müllerian hormone (AMH), also known as Müllerian-inhibiting hormone (MIH), is a glycoprotein hormone structurally related to inhibin and activin from the transforming growth factor beta superfamily, whose key roles are in growth differen ...

by the

Sertoli cells Sertoli cells are a type of sustentacular "nurse" cell found in human testes which contribute to the process of spermatogenesis (the production of sperm) as a structural component of the seminiferous tubules. They are activated by follicle-stimula ...

of the

testes A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...

Development in females

In the female the paramesonephric ducts persist and undergo further development. The portions which lie in the ''genital cord'' fuse to form the

and

. This fusion of the paramesonephric ducts begins in the third month, and the septum formed by their fused medial walls disappears from below upward. The parts outside this cord remain separate, and each forms the corresponding Fallopian tube. The

ostium of the fallopian tube The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In ot ...

remains from the anterior extremity of the original tubular invagination from the abdominal cavity. About the fifth month a ring-like constriction marks the position of the cervix of the uterus, and after the sixth month the walls of the uterus begin to thicken. For a time the vagina is represented by a solid rod of epithelial cells. A ring-like outgrowth of this epithelium occurs at the lower end of the uterus and marks the future

vaginal fornix The fornices of the vagina (sing. fornix of the vagina or fornix vaginae) are the superior portions of the vagina, extending into the recesses created by the vaginal portion of cervix. The word "fornix" is Latin for "arch". Structure There are t ...

. At about the fifth or sixth month the lumen of the vagina is produced by the breaking down of the central cells of the epithelium. The

hymen The hymen is a thin piece of mucosal tissue that surrounds or partially covers the external vaginal opening. It forms part of the vulva, or external genitalia, and is similar in structure to the vagina. In children, a common appearance of the ...

represents the remains of the sinus tubercle .

Gonads

The gonads are the precursors of the

in males and

ovaries The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...

in females. They initially develop from the mesothelial layer of the peritoneum.

Ovaries

The ovary is differentiated into a central part, the medulla of ovary, covered by a surface layer, the germinal epithelium. The immature ova originate from cells from the dorsal endoderm of the

yolk sac The yolk sac is a membranous sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac'' is ...

. Once they have reached the gonadal ridge they are called

oogonia An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in lar ...

. Development proceeds and the oogonia become fully surrounded by a layer of connective tissue cells (pre-granulosa cells). In this way, the rudiments of the ovarian follicles are formed. The embryological origin of granulosa cells, on the other hand, remains controversial. Just as in the male, there is a

gubernaculum The paired gubernacula (from Ancient Greek κυβερνάω = pilot, steer) also called the caudal genital ligament, are embryonic structures which begin as undifferentiated mesenchyme attaching to the caudal end of the gonads (testes in mal ...

in the female, which pulls it downward, albeit not as much as in males. The gubernaculum later becomes the proper

ovarian ligament The ovarian ligament (also called the utero-ovarian ligament or proper ovarian ligament) is a fibrous ligament that connects the ovary to the lateral surface of the uterus. Structure The ovarian ligament is composed of muscular and fibrous tissu ...

and the

round ligament of the uterus The round ligament of the uterus is a ligament that connects the uterus to the labia majora. Structure The round ligament of the uterus originates at the uterine horns, in the parametrium. The round ligament exits the pelvis via the deep inguina ...

Testes

The periphery of the testes are converted into the tunica albuginea. Cords of the central mass run together and form a network which becomes the

rete testis The rete testis ( ) is an anastomosing network of delicate tubules located in the hilum of the testicle (mediastinum testis) that carries sperm from the seminiferous tubules to the efferent ducts. It is the counterpart of the rete ovarii in fe ...

, and another network, which develops the

seminiferous tubules Seminiferous tubules are located within the testes, and are the specific location of meiosis, and the subsequent creation of male gametes, namely spermatozoa. Structure The epithelium of the tubule consists of a type of sustentacular cells known ...

. Via the rete testis, the seminiferous tubules become connected with outgrowths from the mesonephros, which form the efferent ducts of the testis. In short, the descent of the testes consists of the opening of a connection from the testis 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 An inguinal hernia is a hernia (protrusion) of abdominal-cavity contents through the inguinal canal. Symptoms, which may include pain or discomfort especially with or following coughing, exercise, or bowel movements, are absent in about a third ...

or an infantile hydrocoele.

Division of cloaca

After the separation of the rectum from the dorsal part of the cloaca, the ventral part becomes the primary

urogenital sinus The urogenital sinus is a part of the human body only present in the development of the urinary and reproductive organs. It is the ventral part of the cloaca, formed after the cloaca separates from the anal canal during the fourth to seventh w ...

. The urogenital sinus, in turn, divides into the superficial definitive urogenital sinus and the deeper anterior vesico-urethral portion.

Definitive urogenital sinus

The definitive urogenital sinus consists of a caudal cephalic portion and an intermediate narrow channel, the pelvic portion.

Vesico-urethral portion

The vesico-urethral portion is the deepest portion, continuous with the allantois. It absorbs the ends of the mesonephric ducts and the associated ends of the renal diverticula, and these give rise to the

trigone of urinary bladder The trigone (a.k.a. vesical trigone) is a smooth triangular region of the internal urinary bladder formed by the two ureteric orifices and the internal urethral orifice. The area is very sensitive to expansion and once stretched to a certai ...

and part of the prostatic urethra. The remainder of the vesico-urethral portion forms the body of the bladder and part of the prostatic urethra; its apex is prolonged to the umbilicus as a narrow canal, the

urachus The urachus is a fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord. The fibrous remnant lies in the space of Retzius, between the transverse fascia anteriorly and ...

, which later is obliterated and becomes the

median umbilical ligament In human anatomy, the median umbilical ligament is an unpaired midline ligamentous structure upon the lower inner surface of the anterior abdominal wall. It is covered by the median umbilical fold. The median umbilical ligament represents the re ...

of the adult.

Prostate

The

prostate The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and phys ...

originally consists of two separate portions, each of which arises as a series of diverticular buds from the epithelial lining of the urogenital sinus and vesico-urethral part of the cloaca, between the third and fourth months. These buds become tubular, and form the glandular substance of the two lobes, which ultimately meet and fuse behind the urethra and also extend on to its ventral aspect. The median lobe of the prostate is formed as an extension of the lateral lobes between the common ejaculatory ducts and the bladder. Skene's glands in the female urethra are regarded as the homologues of the prostatic glands. The

bulbourethral glands The bulbourethral glands or Cowper's glands (named for English anatomist William Cowper) are two small exocrine glands in the reproductive system of many male mammals (of all domesticated animals, they are absent only in dogs). They are homolog ...

in the male, and Bartholin's gland in the female, also arise as diverticula from the epithelial lining of the urogenital sinus.

External genitalia

Until about the ninth week of gestational age the external genitalia of males and females look the same, and follow a common development. This includes the development of a genital tubercle and a membrane dorsally to it, covering the developing

urogenital opening The urogenital opening is where bodily waste and reproductive fluids are expelled to the environment outside of the body cavity. In some organisms, including birds and many fish, discharge from the urological, digestive, and reproductive system ...

, and the development of the labioscrotal fold, also called the urogenital fold, and the labioscrotal swelling.Keith L. Moore, T. V. N. Persaud, Mark G. Torchia, ''The Developing Human: Clinically Oriented Embryology'' 10th Ed. Elsevier Health Sciences, 2015
pp. 267–269
/ref> Even after differentiation can be seen between the sexes, some stages are common, e.g. the disappearing of the membrane. On the other hand, sex-dependent development include further protrusion of the genital tubercle in the male to form the glans of the penis and in the female, the clitoral glans. The urogenital fold evolves into the shaft of the penis in males and the shaft of the clitoris in females; the labioscrotal swelling evolves into the scrotum in males, and into the

labia majora The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia majo ...

in females.

Common development

Before differentiation

=Urogenital membrane

= There is initially a cloacal membrane, composed of ectoderm and endoderm, reaching from the

umbilical cord In placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologi ...

to the tail, separating the cloaca from the exterior. After the separation of the rectum from the dorsal part of the cloaca, the ventral part of the cloacal membrane becomes the ''urogenital membrane''.

=Genital tubercle

= Mesoderm extends to the midventral line for some distance behind the umbilical cord, and forms the lower part of the abdominal wall; it ends below in a prominent swelling, the cloacal tubercle, which after the separation of the rectum becomes the

genital tubercle A genital tubercle or phallic tubercle is a body of tissue present in the development of the reproductive system. It forms in the ventral, caudal region of mammalian embryos of both sexes, and eventually develops into a primordial phallus. In t ...

. Dorsally to this tubercle the sides aren't really fused. Rather, the urogenital part of the cloacal membrane separates the ingrowing sheets of mesoderm.

=Phallus

= The genital tubercle develops into the

primordial phallus In embryology, the primordial phallus refers to the clitoris of a female or the penis in the male, particularly during fetal development of the urinary and reproductive organs, before sexual differentiation is evident. This is also the case for ...

, the first rudiment of the penis or clitoris. The terminal part of the phallus, representing the future glans becomes solid. The remainder of the phallus, which remains hollow, is converted into a longitudinal groove by the absorption of the urogenital membrane. The term genital tubercle, however, still remains, but only refers to the future glans

=Urogenital opening

= In both sexes the phallic portion of the

extends on to the under surface of the cloacal tubercle as far forward as the apex. At the apex the walls of the phallic portion come together and fuse, obliterating the

. Instead, a solid plate, the urethral plate, is formed. The remainder of the phallic portion is for a time tubular, and then, by the absorption of the urogenital membrane, it establishes a communication with the exterior. This opening is for a while the primitive urogenital opening, and it extends forward to the corona glandis.

After differentiation

The following developments occur in both males and females, although a difference in the development between the sexes already can be seen: *The

corpus cavernosum penis A corpus cavernosum penis (singular) (literally "cave-like body" of the penis, plural corpora cavernosa) is one of a pair of sponge-like regions of erectile tissue, which contain most of the blood in the penis during an erection. Such a corpus ...

, and the

corpus cavernosum of clitoris The corpus cavernosum of clitoris is one of a pair of sponge-like regions of erectile tissue of the clitoris in women. It is made of a sponge-like tissue that fills with blood during clitoral erection. This is homologous to the corpus cavernosu ...

, and the

corpus spongiosum penis The corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis. It is also called the corpus cavernosum urethrae in older texts. Anatomy The proximal part of the corpus spongiosum is expanded to form the ure ...

arise from the mesodermal tissue in the phallus; they are at first dense structures, but later vascular spaces appear in them, and they gradually become cavernous. *The prepuce in both sexes is formed by the growth of a solid plate of ectoderm into the superficial part of the phallus; on coronal section this plate presents the shape of a horseshoe. By the breaking down of its more centrally situated cells the plate is split into two lamellæ. Thus, a cutaneous fold, the prepuce, is liberated and forms a hood over the glans.

Female

In the female, a deep groove forms around the phallus. The sides of it grow dorsalward as the

labioscrotal folds The labioscrotal swellings (genital swellings or labioscrotal folds) are paired structures in the human embryo that represent the final stage of development of the caudal end of the external genitals before sexual differentiation. In both males a ...

, which ultimately form the labia majora in females. The labia minora, in contrast, arise by the continued growth of the lips of the groove on the under surface of the phallus; the remainder of the phallus forms the

clitoral glans The clitoris ( or ) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible portion – the glans – is at the front junction of the labia minora (inner lips), above the ope ...

Male

The labioscrotal folds extend around between the pelvic portion and the anus, and form a scrotal area. During the changes associated with the descent of the testes this scrotal area is drawn out to form the scrotal sacs. The penis is developed from the phallus. As in the female, the urogenital membrane undergoes absorption, forming a channel on the under surface of the phallus; this channel extends only as far forward as the

corona glandis The corona of glans penis or penis crown refers to the rounded projecting border that forms at the base of the glans in human males. The corona overhangs a mucosal surface, known as the neck of the penis, which separates the shaft and the glans ...

Urogenital opening

Later, this opening, which is located on the dorsal side of the penis, closes from behind forward. Meanwhile, the urethral plate of the glans breaks down centrally to form a median groove continuous with the primitive ostium. This groove also closes from behind forward, leaving only a small pipe running in the middle of the penis. Thus, the urogenital opening is shifted forward to the end of the glans.

Diagram of internal differentiation

A.—Diagram of the primitive urogenital organs in the embryo previous to sexual distinction. * 3. Ureter. * 4. Urinary bladder. * 5. Urachus. * cl. Cloaca. * cp. Elevation which becomes clitoris or penis. * i. Lower part of the intestine. * ls. Fold of integument from which the labia majora or scrotum are formed. * m, m. Right and left Müllerian ducts uniting together and running with the Wolffian ducts in gc, the genital cord. * ot. The genital ridge from which either the ovary or testis is formed. * ug. Sinus urogenitalis. * W. Left Wolffian body. * w, w. Right and left Wolffian ducts. B.—Diagram of the female type of sexual organs. * C. Greater vestibular gland, and immediately above it the urethra. * cc. Corpus cavernosum clitoridis. * dG. Remains of the left Wolffian duct, such as give rise to the duct of Gärtner, represented by dotted lines; that of the right side is marked w. * f. The abdominal opening of the left uterine tube. * g. Round ligament, corresponding to gubernaculum. * h. Situation of the hymen. * i. Lower part of the intestine. * l. Labium majus. * n. Labium minus. * o. The left ovary. * po. Epoophoron. * sc. Corpus cavernosum urethrae. * u. Uterus. The uterine tube of the right side is marked m. * v. Vulva. * va. Vagina. * W. Scattered remains of Wolffian tubes near it (paroöphoron of Waldeyer). C.—Diagram of the male type of sexual organs. * C. Bulbo-urethral gland of one side. * cp. Corpora cavernosa penis cut short. * e. Caput epididymis. * g. The gubernaculum. * i. Lower part of the intestine. * m. Müllerian duct, the upper part of which remains as the hydatid of Morgagni; the lower part, represented by a dotted line descending to the prostatic utricle, constitutes the occasionally existing cornu and tube of the uterus masculinus. * pr. The prostate. * s. Scrotum. * sp. Corpus cavernosum urethrae. * t. Testis in the place of its original formation. * t’, together with the dotted lines above, indicates the direction in which the testis and epididymis descend from the abdomen into the scrotum. * vd. Ductus deferens. * vh. Ductus aberrans. * vs. The vesicula seminalis. * W. Scattered remains of the Wolffian body, constituting the organ of Giraldès, or the paradidymis of Waldeyer.

References

In-line

General

Henry Gray (1821–1865). Anatomy of the Human Body. 1918.

External links

Animations of gonadal sex, duct differentiation, and external genital development at AboutKidsHealth.ca
{{DEFAULTSORT:Development Of The Reproductive System Embryology of urogenital system Andrology Gynaecology