From the cell to the individual!
As we have seen, cells are living organisms that reproduce by cell division.
In a process called mitosis, a mother cell will give rise to two daughter cells, identical to the "original" mother cell!
The human body, this "giant cell" has organs, the "organs of reproduction" that allows it to perpetuate the species and the bursting of life.
These organs struck with taboo are at the origin of the most important and impressive energy: life!
The baby factory!
Oviduct
The reproductive system is the system responsible for procreation.
While all other systems are substantially identical in women and in men, the reproductive system is gender specific.
As far as reproduction is concerned, men and women have very specialized and different organs!
Then, Ladies first!
The oviduct or fallopian tubes is the conduit through which the egg passes, the ovule connects the ovary to the uterus.
The ovaries
The ovaries are female gonads,
The main reproductive organs of the female reproductive system.
They generate female gametes(ova or egg), which contain half the genetic instructions necessary for the development of an embryo.
The ovaries also play the role of endocrine glands and produce progesterone and estrogens.
These hormones are sex hormones governing the early development of the female reproductive system and contributing to the menstrual cycle.
The ovaries take the form of nodular bodieslocated on both sides of the uterus, set back and below the fallopian tubes.
Each ovary is about 4cm long and 2cm wide.
The ovary is attached to the pelvic wall by a suspensory ligament.
The ovary being within the broad ligament, connects the ovaryto the uterus.
An ovary consists of many ovarian folliclessurrounded by a layer called the cortex.
These follicles are immediately below the ovarian surface and are abundantly fed by the blood vessels.
The eggs begin to develop within the follicles.
During ovulation,a follicle gradually approaches the surface of the ovary and ruptures;
The ovule and the liquid content of the follicle are released to the outside of the ovary and conveyed into the fallopian tube by the currents caused by the movements of the eye lashes covering the fringes.
The ovaries are homologous to the testicles in humans.
The first house!
The uterus corresponds to the second duct forming the internal genital organs of the female reproductive system.
The uterus is a hollow muscle organ with thick, pear-shaped walls.
It is found in the pelvic cavity, between the bladder and the rectum.
The fallopian tubes open into the upper part of the uterus, on either side of the latter.
The lower part of this structure opens into the vagina.
The upper part of the uterus is suspended within the pelvic cavity by means of numerous ligaments; The lower part of the uterus is surrounded by the fibrous tissue of the pelvis.
The main part of the uterus, of triangular form, is called the body; It narrows in a small narrowing known as the isthmus.
The part of the body between the orifices of the fallopian tubes is called the bottom.
The cervix corresponds to the narrow segment located at the bottom of the uterus and leading to the vagina.
The uterus is about 7.5cm long, 5cm wide at the top and about 2.5cm thick; It weighs between 30 and 40 grams.
The body of the uterus consists of three layers.
The most important is the intermediate layer, made up of smooth muscles and able to stretch.
The fertilized ovum will nest in the utérine wall and be retained in the uterus during its development.
When the fertilized egg develops, transforming into an embryo and then into a fetus, the uterus increases considerably!
The increase in size is partly due to pre-existing muscle growth, but also to the development of new fibers.
After delivery, the uterus returns to its usual size.
It weighs about 42gr, but its cavity is larger, its vessels are tortuous, and its muscular layers more definite;
Furthermore, the outer orifice is more marked, and its edges have one or more cracks.
The male reproductive system
The first human cell is called "egg".
It results from the fusion of two sexual cellscalled gametes:
A male or spermatozoid gamete, coming from the father and a female gamete, or ovum from the mother.
The human egg, devoid of reserves, develops in the maternal organism which ensures its subsistence during pregnancyand then after birth by breast feeding.
The transition from childhood to adult is characterized by a series of physical, psychological and emotional changes.
Physically, puberty corresponds to the maturation of the genital organs(primary sexual characteristics) and the appearance of specific peculiarities(secondary sexualcharacteristics)resulting from the activity of the hormones.
These transformations take several years to be accomplished.
The age of onset of morphological changes and the rate of change from one stage of development to the next vary widely from one child to another.
However, once initiated, these pubertal changes take place in a well-established chronological sequence.
Thus, the study of the male genital tractincludes that of the sperm-forming organsand the paths they follow!
Anatomy of the organs
Testis
The testes are glands that develop gametes.
The testes are located outside the abdominal cavity.
This extra-abdominal situation allows them to remain at a temperature slightly lower than that of the body, an indispensable condition for the formation of viable spermatozoa!
The testes are male genital glands,
Producing sperm.
These oval-shaped glands, two in number, measure about 3.8cm in length and 2.5cm in diameter.
The testes perform a dual function, exocrine(formation of spermatozoa) and endocrine(secretion of male hormones by Leydig cells, located between the seminiferous tubes).
The testicles are enclosed in a double external sac, called scrotum.
The scrotum is the protective skin pocher that contains the testes.
It is located in the groin, outside the abdominal cavity.
After puberty, the scrotum and skin around it gradually become covered with hair.
These pubic hair persist throughout adult life.
The epididymis
The epididymis is the conduit of the male reproductive system directly attached to the testicles.
It is part of the internal genital organs of man.
The epididymis is composed of a central portion, or body; Of a swollen upper region, called the head; And a pointedlower end, the tail, being in the continuity of the vas deferens.
Fifteen or twenty ducts penetrate into the albuginea which envelops the testicle and transport the seminal fluid from the testis to
The epididymis.
The body and tail of the epididymis constitute a single extremely twisted conduit.
When the convolutions of this canal are unwound, the latter is more than 6 meters long.
Spermatozoa leaving the tail of the epididymis penetrate the vas deferens.
Vas deferent
The vas deferens, is one of the ducts of the male reproductive system.
The vas deferens acts as an excretory channel of the testis and corresponds to the extension of the epididymis.
The most distal portion of the epididymis, or tail, is very twisted.
As the ascent of the epididymis
along the posterior border of the testicle, this duct is progressively folded.
In the pelvic cavity, the vas deferens is located behind the peritoneal membrane and the lateral wall of the pelvis.
At its extremity, it is oriented downwards towards the base of the prostate, where it narrows and joins the base of the seminal vesicle, thus forming the ejaculatory canal.
Prostate
The prostate is one of the accessory glands of the male reproductive system.
The prostate is a compact, partly muscular structure.
It is located immediately below and around the internal opening of the urethra.
It is covered with a fibro-muscular layer known as the prostatic capsule.
The prostate is approximately the size of a nut and is found in the pelvic cavity below the lower part of the pubic symphysis and at the front of the rectum.
This position allows it to be easily palpable, especially when its volume has increased.
Its lower portion, larger, sometimes presents a deep furrow which imperfectlyseparates the prostate into a right lobe and a left lobe.
The glandular tissue of the prostate is composed of numerous glands opening into 12 to 20 small excretory ducts, which in turn open at the level of the prostatic portion of the urethra.
The liquid produced by the prostate during ejaculation contains enzymes and other substances to activate the spermatozoa!
Seminal vesicles
A seminal(bag-shaped)vesicle is closely associated with each vas deferens,
It's one of the ducts belonging to the mâle reproductive system.
A seminal vesicle is generally about 7.5cm long and consists of a single tube wound on itself.
It is covered with a mucous membrane;
The calciform cells present in the membrane secrete a milky, pale brown liquid containing sugars, prostaglandins and other substances.
This fluid constitutes about two-thirds of the sperm.
The anterior surface of the seminal vesicle is in contact with the bladder, and its posterior surface rests on the rectum.
The lower extremities of the two vesicles are pointed and converge towards the base of the prostate.
At this point, each vesicle joins its respective vas deferens, thus forming the ejaculatory canal.
Bulbar-urethral gland
The bulb-urethral glands or glands of Cowper, are accessory glands of the male reproductive system.
The Cowper glands are two yellowish rounded glands, the size of a pea, located at the back and sides of the upper urethra.
Each gland is composed of lobules which produce an alkaline mucus.
A single conduit carries this mucus into the urethra.
Mucus is used to neutralize traces of acids(from urine)that can interfere with spermmotility.
The Urethra
The urethra is one of the excretory ducs of the urinary system, and of the reproductive system.
The urine produced in the kidneys passes through the ureters, where it is collected in the bladder and is discharged through the urethra.
In men, the urethra extends from the internal opening of the urethra(located in the bladder) to the external orifice of the urethra(or external urinary meatus) at the end of the penis.
It is divided into three parts:
The prostatic, membranous and cavernous (spongy)parts.
Except when passing urine or sperm, the major part of the urethral canal takes the form of a tiny slit, the upper and lower surfaces of which are in contact.
In male adults, the urethra is between 17.5 and 20cm long.
The prostatic part, the widest and most easily dilatable of the canal, traverses the prostate almost vertically,
From its base to its apex.
On the posterior wall of the prostatic urethra, where the ejaculatory ducts join the urethra, the urethral crest forms the seminal colliculus.
The prostatic urethra narrows when it reaches the membranous urethra.
At this junction, it becomes the narrowest and least dilatable part of the urethra(except for the external urinary meatus).
This part of the male urethra passes through the progenital diaphragm and receives channels from the Cowper glands.
It is entirely surrounded by two sphincters(an internal sphincter independent of the will and an external sphincter depending on the will) that ensure muscular control of the flow of urine to the outside.
The cavernous(or spongy) part is the longest part of the urethra.
It travels through the corpora cavernosa of the penis.
The spongy part is divided into two sections.
The bulbar section is located inside the penis bulb in the superficial perineal space, and the pendulous urethra is in a more distal position in the pendular portion of the penis.
