The system that encompasses the reproduction organs is called the “genital system” and it is divided into two: the internal and the external genital systems in both men and women.
In this section, the anatomies of the genital systems that sustain the functions of reproduction and urination in both women and men are explained in detail.
ANATOMY OF FEMALE GENITAL SYSTEM
(Schema1) 1. External Genital Area 2.Clitoris 3.Labium Majora 4. Labium Minora 5.Anus 6.Vagina 7.Urethra
External Genital System: This part is called the “vulva” in Latin. It is characterized by the folds formed on the external genital system by the skin that encompasses the body.
Internal Genital System: This system consists of the organs between the sacrum, which is made up of the lower part of the back spinal bone and the hip bone, and the “bone frame” (Pelvis) formed by the coccyx. The organs situated here are almost entirely protected by the frame of the bones.
External Genital System in Women
The vulva or the external genital system is the name of the area delimited by skin at the top by the Mons Pubis (which is the puff where the pubic bones meet in the middle) and from below by the anus which is the exit hole of excrement, and on the sides by the Labia Majora.
Mons Pubis is a region which is covered by a layer of fat on the bottom and covered by hair on the top. Just below this puff, there is the structure called the clitoris. Further below, there is the bone joint called the symphysis pubis.
In the external genital system, underneath the fat layer, there are many “pelvic base muscles” that function during sexual intercourse and when holding the pee and the feces or in their secretion.
Outer (Big) Labia
The outer or the big labia (labiums), which are covered with genital hair on top and with a fat layer underneath, are situated symmetrically on the right and left sides of the vulva. This is called the “Labia Majora” in Latin.
Inner (Small) Labia
The inner or the small labia (labiums) are located symmetrically on both sides in the inner section that forms the vaginal entrance surrounded by the outer labia. There is no hair on top of the inner labiums and there is no fat layer underneath either. Normally, as the small labiums are small, they are covered by the outer labiums and thus invisible. Yet, in certain cases they might be ample and protruding outwards.
Vagina entrance (Vestibulm)
This is the 1-2 cm part that is situated next to the inner lips and continues up to the hymen. Its Latin name is “Vestibulm”.
This part conjoins with the vagina, when the hymen becomes torn after the first sexual intercourse. Inflammations in the Vestibulm may cause the person to feel pain during sexual intercourse(vulvar vestibular syndrome).
The maidenhead or the hymen in Latin is a pellicle situated 2-3 cm inside the vaginal entrance and has a hole in the middle.
The maidenhead that becomes torn with the first intercourse enables the vaginal entrance and the vagina to conjoin. It is important from the criminal and sociological perspectives rather than in terms of its function.
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The clitoris is situated just below the pubic puff (Mons Pubis) and is the counterpart in women of the penis head (penis glans) in men. Over the top and the sides, it is surrounded by the inner lips. Just below the clitoris there is the urinary hole (urethral orifice) and just below the urinary hole the vaginal entrance is located.
In addition to the button shaped part of the clitoris that is visible from the outside, there exist two arms wholly embedded into the vulva and extending to the sides. In this regard, the clitoris, in total, has a structure in the shape of a Y.
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(Schema2) 1. Outer labia 2.Clitoris body 3.Clitoris 4.Inner labia 5.Urethral orifice 6.Clitoral skin
The clitoris is an area where there is pleasure nerve density in women. During sexual intercourse, the clitoris hardens like the penis of men. As a result of the fact that the blood vessels in it are filled, the clitoris carries out a very important function in a woman’s orgasm.
Urinary Hole (urethral orifice)
The structure that is located just below the clitoris and just above the vaginal entrance is the urinary hole where the urinary channel ends. In Latin it is called the “Urethral Orifice”. Its function is to discharge the urine that comes from the urinary bladder.
The part that is located between the point where the outer lips join at the back and the anus and contains the muscles that control urination and defecation is called the “perineum”. It is an erogenous (pleasurable) area that both males and females have.
At the same time, the perineum by relaxing during childbirth eases the birth. In order to ease the birth even further and to prevent the child’s head from tearing the muscles, during the protrusion of the child’s head, an incision is applied to the perineum. (Perineal incision, episiotomy) Later on this incision is mended by stitching.
The Bartholins and Skene glands function in providing lubrication for the outer genital area and provide lubrication during sexual intercourse and prevent dryness.
While the Bartholins glands are located to the right and left just at the entrance part of the vagina, the Skene glands are situated at the vagina entrance around the urinary hole and along the urinary channel. It is said that the Skene glands are responsible for the liquid flow during a woman’s orgasm, which is referred to as “female ejaculation”.
The anus is the last section of the large intestines and it comes after the rectum. It has the duty of holding and discharging the feces accumulated in the intestines at necessary times. (Defecation)
Because the anus is situated in close proximity to the vagina, unless necessary hygienic precautions are taken, there is the risk for the bacteria in the anus to spread to the vagina, thus creating a risk of infection. Thus, women, while cleaning themselves in the toilet, should wipe from front to back.
The Internal Genital System in Women
The internal genital system in women consists of the vagina, urinary channel (urethra), cervix, womb (uterus), endometrium, fallopian tubes on both sides, and the ovaries.
(Schema3) Woman’s Genital System, 1.Spine (back) 2.Cervix 3.Rectum 4.Vagina 5.Anus 6.Outer Lip 7.Inner Lip 8.Clitoris 9.Urethra 10 Pubic Bone 11. Urinary Bladder 12.Uterus 13.Fimbria 14.Ovary 15.Tube
(Schema 4) 1. Vagina 2. Supportive muscle of ovary 3.Ovary 4.Uterus 5.Cervix 6.Fornix 7.Vagina
The vagina, starting from the vaginal entrance and extending up to the cervix, is a channel approximately 9 cm in length with the ability to stretch and loosen almost like an accordion.
The pockets formed at the point where the vagina ends are called the “fornix vagina”. After this area, the cervix begins.
In women, the vagina is a transition zone and has four functions.
This is the channel where intercourse takes place, the birth channel where the baby is born, the channel through which the urinary channel passes, and the menstrual channel where the menstrual blood is discharged.
During intercourse, the Bartholins and the Skene glands, located at the vaginal entrance, lubricate the vagina and the vaginal entrance.
Urinary Channel (Urethra)
This is the tube located between the point where the urine exits the urinary bladder and where it is then discharged from the urethra orifice.
The urethra is the last step of the urinary system (urine disposal system).
Anatomically, the female urethra is quite short compared to its counterpart in men. Because of this, women are more frequently subjected to urethra infections when compared to men. Again, the reason for the sensation of urination felt during sexual intercourse by some women is due to this. With the irritation of this part, there might be complaints such as frequent urination and painful urination.
The cervix is a hard and cone shaped organ located at the entrance to the uterus that acts almost as a strainer preventing the passage of microorganisms from the vagina to the uterus and the Fallopian tubes. Its Latin name is the cervix.
On the contrary to the muscle structure of the uterus, the cervix is made of collagen and elastic bond tissue and does not contain any nerves. Because of this there is no sensation of pain in this region.
Moreover, the cervix has functions such as to allow healthy sperms to enter, especially in the ovulation period, and to open up and hold back to let the baby descend to the vagina during birth.
During birth, with the full opening of the cervix, the uterus and vagina conjoin and the descent of the baby begins.
The uterus is a pear shaped organ that has at its end the cervix, at the sides the Fallopian tubes in the shape of horns, and possess the skill of contraction due to its strong muscle structure. The pellicle situated at the space in the uterus is called the “endometrium”.
The uterus has an approximate weight of 50 grams in non-pregnant women. During pregnancy it enlarges almost 20 times and reaches the weight of 1000 grams. Its job is to provide the appropriate environment for the baby to grow and, during birth, with contractions, to enable the baby to descend.
The uterus is such an interesting organ that it can enlarge 20 times its initial weight towards the end of pregnancy and yet, after birth, it can return to its original size in 40 days. In our body, we do not have a second organ that can enlarge this much and shrink back to its original size!
For women who enter menopause, together with the ovaries, the size of the uterus also shrinks gradually.
The space (lining) in the uterus is called the “endometrium”. The function of the endometrium is to establish the menstrual cycle by being shed during every monthly period and, in case of pregnancy, to provide a place for the fertilized egg cell (zygote) to settle. The endometrium is regenerated in each menstrual cycle.
Fallopian Tubes (Oviduct)
These are the horn shaped channels situated at both sides of the uterus. The Fallopian tubes (Oviduct) are the place where the sperm and the egg cells become united during the formation stage of pregnancy.
These tubes are mobile organs and this mobility enables them to catch the eggs discharged from the ovaries. In the same stage, the sperm discharged into the vagina, with their ability to swim, reach the tubes and fertilize the eggs in the tubes (fertilization). This way, the initial stage of pregnancy happens in the Fallopian tubes; thus, for a successful pregnancy healthy fallopian tubes are an absolute requirement.
The ovaries are approximately 2-3 cm in size, almond shaped organs, neighboring the open parts of the fallopian tubes (fimbria). They possess the primary function of forming eggs and secreting certain female hormones.
Every month, during menstruation, a “chosen egg cell” (dominant follicle) that starts off 2-3 mm in diameter and reaches up to 20 mm, together with the secretion of the estrogen hormone, is discharged from the ovaries by cracking off from the ovaries. This process is called “ovulation”.
The discharged egg cell is caught and taken into the channel in the tubes by the adhesive tip points of the tubes (fimbria). If there is sexual intercourse during this period and sperms are discharged, they reach the tubes by swimming. The sperm and the egg cell unite in the tubes (Fertilization).
The fertilized egg cell, meanwhile, splits from the tubes and, after a 6-7 day journey settles in the endometrium, and in this way a pregnancy begins.
(Schema 5) 1) being fertilized by a sperm the settling of a egg in the uterus, which is discharged from the ovaries 2) uterus 3) fertilized egg 4) fallopian tube 5) zygote 6) fertilization 7) the egg 8) an ovary
During the period after the egg is discharged, the “progesterone hormone” secreted from the ovaries enables the embryo growing in the uterus to cling.
If there is no pregnancy, the egg cell, discharged from the ovaries, is then expelled from the constantly thickening endometrium due to its inability to feed the egg, all of which means that the person then has her period. During menstruation, the cervix that is normally closed by opening up allows the blood to be expelled.
In women, the estrogen and progesterone hormones have many effects in the entire body especially in the heart and the skeletal system. Therefore, with menopause, the ovaries lose their function and troubles such as heart diseases, osteoporosis and many more start to emerge in women.
ANATOMY OF THE MALE GENITAL SYSTEM
The male genital system, just like the female genital system, can be divided into the internal and the external genital organs. The male external genital system consists of the penis and the sac (scrotum) which contains the testicles.
(Schema 6) 1) male genital system 2) urinary bladder 3) seminal vesicle 4) rectum 5) anus 6) vas deferens 7) testicle 8) scrotum 9) epididymis 10) penis 11) urethra 12) prostate
The internal genitalia consists of the two testicles located in a sac, the epididymis, seminal vesicle, prostate and certain secretion channels (vas deferens) and glands (Cowper gland, etc.).
The penis is a cylindrical spongiose organ which in an adult male is 5-12 cm long and 3-5 cm thick. In it, there are specialized pores that contain blood vessels.
As a result of sexual stimulation, as the pores and the space in them become filled with blood, the penis grows in diameter and reaches almost two times its actual size. When the sexual stimulation is over, it goes back to its original size in a very short time.
The length of the penis differs according to race and the person. Contrary to common supposition, the thickness of the penis is more important than its length in satisfying the man’s partner. (In fact, more important than its thickness is how frequently the person experiences sexual stimulation when he/she is together with her/his partner.)
The penis is comprised of two parts: the head (glans) and the body (corpus).
The head of the penis is covered with the preputium and, when the male is circumcised, this part is revealed. In men who are not circumcised, the head part located in the preputium becomes exposed with erection; later, as the penis returns to its initial size the head is once more covered by skin.
The head of the penis (glans penis) is one of the most sensual areas of a man and, with the high amount of nerve endings it possesses, plays the most significant role in male orgasm.
Through the penis the “urethra” (urinary channel) passes. The urethra is the tube between the urinary bladder and the urinary hole and through this channel the urine passes and is ejected. Another function of the urethra is to ejaculate semen during male orgasm.
The male urethra is much longer compared to the female urethra and because of this urinary channel infections are much more rarely seen in men compared to women.
The scrotum is the name of the sac that contains two testicles situated at the right and the left sides, some of the sperm channels and many vessel structures.
The temperature in the sac is approximately 2 degrees lower than body temperature in order to prevent sperms from dying and to increase sperm production (spermatogenesis). This is the reason why the sac is outside the body.
In cold weather, in order to prevent the sperm from becoming cold, the scrotum by contracting itself takes the testicles into the body, in hot weather; in the exact opposite way, by relaxing itself it maintains its equilibrium.
Testicles and Sperm Production
The testicles are two organs, located in a sac, where sperms are produced and the male hormone called testosterone is secreted.
Their sizes differ from person to person; each one is about 20-30 grams, 4-5 cm long and 2-2.5 cm thick. Although they are the same size, the left testicle is situated a bit lower from the right one.
In each testicle there exist small and twisted sperm channels. These little channels produce sperms under the effect of the “FSH hormone” secreted by the pituitary gland located in the brain.
Testicles produce the “testosterone hormone”, also known as the male hormone, under the effect of the “LH hormone” again secreted by the pituitary gland.
Through puberty, with the effect of the testosterone hormone whose secretion is increased, there emerge certain changes in children such as a deepening of the voice, the appearance of facial and pubic hair and the development of the body’s muscles (secondary sexual characteristics). Sperm production also starts a short time after the beginning of puberty.
In an adult male, testosterone provides prolonged sperm production and the continuation of the characteristics intrinsic to the male sex.
The structure of the sperm cell: The sperm cell is 0.05 mm in length and consists of three parts: the head, body (middle part) and tail. Sperm cell microscopic view (schema 7).
(Schema 7) 1) acrosome 2) cell membrane 3) nucleus 4) centriole 5) mitochondria 6) sperm cell structure 7) head 8) tail (flagellum) 9) body
The head part has two important features: one is the “acrosome” organelle situated at the tip which contains corrosive enzymes that enable the sperm to enter the egg cell. The “litik enzymes” located in the acrosome establishes fertilization by rupturing the outer membrane of the egg.
The other function of the head part is to protect the genetic material belonging to the X and Y chromosomes subsistent in the nucleus. The merging of the egg with a sperm that has an X chromosome causes an embryo to be female and the merging of the egg with a sperm that has a Y chromosome results in a male embryo.
Due to the mitochondria situated at the middle section of the sperm, the necessary energy (ATP) for mobility is sustained.
Also, due to the micro-filiforms located at the tail, sperm can sustain its mobility (sperm motility).
Sperm Production (Spermatogenesis)
In each testicle, there are many capillary pipes that are very thin and folded into each other. Sperm cells form and mature in these pipes in approximately 74 days. Sperm production is continuous and the sperm produced is always stored and ready for ejaculation.
Sperm cell production, just like egg cell production, actually takes place by the division of a cell carrying 46 chromosomes into exact halves. In the cells of men, there exist one X and one Y chromosomes as the sex chromosomes. In women, both of the chromosomes have the Y structure.
Sperm cells, during their formation stage, either take X or Y chromosomes from the sex chromosomes.
If the sperm cell that fertilizes the egg has the Y chromosome the sex of the baby becomes male and if it has the X chromosome then the sex of the baby becomes female.
The small channels in the testicles continue with the structure called the “epididymis” located just above the testicles. The epididymis is the area where the sperm cells continue to mature. It has the function of a store for the cells and continues with the main sperm transfer channel called the “vas deferens”.
Other glands and Channels
The seminal vesicles, Prostate gland and Cowper glands discharging their secretions into the main sperm channel, enable the semen to take its final shape. All the secretions secreted from the glands have nurturing and mobility increasing effects over the sperm cells. The fluid that has sperm cells in it is called “the semen or the ejaculate”. The semen which is approximately 4 ml in volume is produced %60 by the seminal vesicle and %20 by the prostate.
As the prostate is the organ situated at the most outer section, during ejaculation the first fluid ejaculated is the prostate fluid and the liveliest sperms are in this liquid. The important point that needs to be known is that during sexual intercourse the first fluid (pleasure liquid) that comes as a result of the stimulation of the male contains sperm cells and because of this, if this liquid is spread into the vagina there might be a chance for pregnancy.
Semen is a 1.5-5cc in volume, opaque gray, sticky and thick liquid that has its distinctive smell and takes a yellow color when it dries. With male orgasm it is ejaculated by a squirt. This event is called ejaculation (to cum).
The semen ejaculated from the body loses its density and becomes almost like water in 15 minutes (liquefaction, melting). In a single ejaculation, a man approximately discharges between 100 and 200 million sperm cells.
In the fertilization of the egg, as much as the number of the sperms, the quality of the sperms, thus their mobility ratio and morphology (structure) are also important. Because not all of the sperms ejaculated in the semen are of quality; for example some of them might be immobile, deformed (incorrectly structured) or dead.
The process of examining the features of the semen in a laboratory is called the “spermiogram test” (semen analysis).