UTERUS

UTERUS

FERTILIZATION

FERTILIZATION

CLITORIS

CLITORIS

UTERUS

UTERUS
The uterus (Latin: uterus) is the female reproductive organ of humans. In this text, you will read all about the uterus and its functions. Anatomy of the Uterus The most important function of the uterus, is to accept a fertilized embryo which implants into its lining. After implantation, the embryo will develop into a fetus and it will stay inside the uterus until birth. The human uterus consists of two segments, being: The body of the uterus (Latin: corpus uteri). This is the largest part of the uterus and is also where the implantation of the embryo takes place. This part of the uterus is also connected to the fallopian tubes. The cervix (Latin: cervix uteri; often abbreviated as cervix). The cervix consists of the neck of the cervix and the ectocervix (often referred to as the ‘portio’). The ectocervix is visible and palpable inside the vagina and is therefore also the connection with the vagina. De portio (the ectocervix) is lined with squamous epithelium, the endocervical canal with mucus producing glandular epithelium. The shape of the uterus The human uterus is pear shaped. Yet the shape of the uterus varies from organism to organism. For instance, animals that generally bear more than one young have two uterine horns (cornua uteri), one left and one right. This way, each uterine horn can harbour one or more young. The size of the uterus of an adult woman is about 5 to 10 centimetres. The uterus of a woman who has never been pregnant before is about the size of a mandarin. After the first pregnancy (and birth) the uterus is slightly bigger. During pregnancy, the uterus will expand and become heavier. The uterus of a pregnant woman can reach a weight of a kilogram. This weight does not include the placenta, amniotic fluid and fetus. When the woman hits menopause, the uterus will shrink slightly. Position of the Uterus The uterus lies deep in the abdomen. To be more precise, the uterus lies within the pelvic diaphragm, directly behind the bladder and in front of the rectum. There are several ligaments that hold the uterus in place. The broad ligament (ligamentum latum) and the round ligament (ligamentum rotondum) are the most important ligaments. What does the uterine wall consist of The uterine wall consists largley of smooth muscle tissue. This layer is called the myometrium. During labour, this smooth muscle tissue will contract (contractions) in order to push the baby out of the body. Just like any organ in the human body, the uterus also needs blood. This blood is supplied by two uterine arteries. The Latin names of these arteries are aa. uteria. These arteries are situated on the left and on the right of the uterus. The endometrium The endometrium is also referred to as the uterine lining and it lines the entire uterine cavity. The endometrium reacts strongly to two female hormones, estrogen and progesterone. Under the influence of estrogen, the uterine lining becomes thicker. The hormone progesterone stimulates the production of more mucus glands. Once the progesterone levels drop (there is less progesterone to be found in the body), the mature and thick uterine lining can no longer stay intact and it must leave the body. When the uterine lining leaves the body through the vagina, we call this menstruation. What many people don't know, is that the endometrium consists of two layers, namely the: Basal layer (lamina basalis). This basal layer always remains present inside the uterus. Functional layer (lamina functionalis). This layer is shed during menstruation and will build up again from the basal layer. Abnormalities and diseases of the uterus There are several abnormalities and diseases that can occur in the uterus. The following abnormalities and diseases may occur in the uterus: Inflammation of the endometrium (endometritis). Polyps Hyperplasia Uterine Cancer Fibroids Malignant tumor Trophoblast abnormalities Cervix polyp Warts Extropion Endometriosis Cervical Cancer Examination of the uterus There are several reasons why an examination of the uterus may be necessary. For example, a woman who consults her GP due to specific symptoms, if a woman is pregnant, or if a woman needs to be examined for uterine cancer. Examination of the uterus can be done in several ways, the method used depends on the reason for the examination. The uterus can be examined in the following ways: Vaginal examination Speculum examination Ultrasound Hysteroscopy Laparoscopy The uterus and the orgasm When a woman is sexually aroused, the uterus will erect slightly. The uterus is pulled in an upward direction, making the vagina slightly longer. When a women has an orgasm, the pelvic muscles and the uterine muscle contract. There are women who barely feel the contraction of the uterine muscle, but there are also women who find that these contractions produce a very pleasant feeling. When the woman has had an orgasm, it can take up to ten minutes before the uterus has returned to its normal position. The Cervix The cervix (also referred to as the cervix uteri) is the narrow, cylindrical portion of the uterus. One end of the cervix protrudes into the top end of the vagina, and the other end is continuous with the corpus uteri. The inside of the cervix is lined with columnar epithelium. In the vagina, the cervix has an opening referred to as the external os (ostium externum). When one looks into the vagina, the part of the cervix that is visible is referred to as the 'portio'. Usually, (excluding during the ovulation) the uterus is blocked by a thick impermeable mucus. This mucosal plug can be found inside the cervix, and it protects the uterus against all kinds of infections. When a woman is pregnant, the cervix dilates shortly before labor. During the dilation of the cervix, the mucosal plug will come out (often accompanied by some blood). This is usually a signal that labor is about to commence. During the menstrual cycle, the cervix undergoes a few changes. Just after menstruation, the cervix is closed and positioned relatively low. In the period leading up to ovulation, the cervix rises, and the structure becomes softer. In this period, the cervix also opens slightly. After the ovulation, the cervix will return to its low position and the opening will close again. Cervical Cancer Cervical cancer is relatively common amongst women and is caused by an infection of Human Papillomavirus (abb. HPV). Cervical cancer can be detected at an early stage by examining a smear (via vaginal examination). If cervical cancer is detected at an early stage, treatment is effective and the woman is likely to be cured of this type of cancer.

Saturday 1 October 2011

VESTIBULE OF THE VAGINA

The Female External Genital
Organs Click here for a schematic diagram of the female external genitalia. The Mons Pubis The mons (L. mountain) pubis is a rounded fatty elevation located anterior to the pubic symphysis and lower pubic region. It consists mainly of a pad of fatty connective tissue deep to the skin. The amount of fat increases during puberty and decreases after menopause. The mons pubis becomes covered with coarse pubic hairs during puberty, which also decrease after menopause. The typical female distribution of pubic hair has a horizontal superior limit across the pubic region. The Labia Majora The labia (L. large lips) are two symmetrical folds of skin, which provide protection for the urethral and vaginal orifices. These open into the vestibule of the vagina. Each labium majus, largely filled with subcutaneous fat, passes posteriorly from the mons pubis to about 2.5 cm from the anus. They are situated on each side of the pudendal cleft, which is the slit between the labia majora into which the vestibule of the vagina opens. The labia majora meet anteriorly at the anterior labial commissure. They do not join posteriorly but a transverse bridge of skin called the posterior labial commissure passes between them. The Labia Minora The labia minora (L. small lips) are thin, delicate folds of fat-free hairless skin. They are located between the labia majora. The labia minora contain a core of spongy tissue with many small blood vessels but no fat. The internal surface of each labium minus consists of thin skin and has the typical pink colour of a mucous
membrane. It contains many sensory nerve endings. Sebaceous and sweat glands open on both of their surfaces. The labia minora enclose the vestibule of the vagina and lie on each side of the orifices of the urethra and vagina. They meet just superior to the clitoris to form a fold of skin called the prepuce (clitoral hood). In young females the labia minora are
usually united posteriorly by a small fold of the skin, the frenulum of the labia minora. The Vestibule of the Vagina The vestibule (L. vestibulum,
antechamber) is the space between the labia minora. The urethra, vagina, and ducts of the greater vestibular glands open into the vestibule. Back to top The External Urethral Orifice This median aperture is located 2 to 3 cm posterior to the clitoris and immediately anterior to the vaginal orifice. On each side of this orifice are the openings of the ducts of the paraurethral glands (Skene's glands). These glands are homologous to the prostate in the male. The Vaginal Orifice This large opening is located inferior and posterior to the much smaller external urethral orifice. The size and appearance of the vaginal
orifice varies with the condition of the hymen (G. membrane), a thin fold of mucous membrane that surrounds the
vaginal orifice. The Greater Vestibular Glands These glands are about 0.5 cm in diameter. They are located on each side of the vestibule of the vagina , posterolateral to the vaginal orifice. They are round or oval in shape and the bulbs of the vestibule partly overlap them posteriorly. From the anterior parts of the glands, slender ducts pass deep to the bulbs of the vestibule and open into the vestibule of the vagina on each side of the vaginal orifice. These glands secrete a small amount of lubricating mucus into the vestibule of the vagina during sexual arousal. The greater vestibular glands (Bartholin's
glands) are homologous with the bulbourethral glands in the male. The Lesser Vestibular Glands These are small glands on each side of the vestibule of the vagina . They open into it between the urethral and vaginal orifices. These glands also secrete mucus into the vestibule, which moistens the labia and the vestibule. Back to top The Clitoris The clitoris is 2 to 3 cm in length. It is homologous with the penis and is an erectile organ. Unlike the penis, the clitoris is not traversed by the urethra; therefore it has no corpus spongiosum. The clitoris is located posterior to the anterior labial commissure, where the labia majora meet. It is usually hidden by the labia when it is flaccid. The clitoris consists of a root and a body that are composed of two crura, two corpora cavernosa, and a glans. It is suspended by a suspensory ligament. The parts of the labia minora passing anterior to the clitoris form the prepuce of the clitoris (homologous with the male prepuce). The parts of the labia passing posterior to the clitoris form the frenulum of the clitoris, which is homologous with the frenulum of the penile prepuce. The clitoris, like the penis, it will enlarge upon tactile stimulation, but it does not lengthen significantly. It is highly sensitive and very important in the sexual arousal of a female. The Bulbs of the Vestibule These are 2 large, elongated masses of erectile tissue that are about 3 cm in length. They lie along the sides of the vaginal orifice, deep to the bulbospongiosus muscles and are homologous with the bulb of the penis. Unlike the penis, however, the bulbs are separated from the clitoris and are separated by the vestibule of the vagina . Back to top Arterial Supply of the Female External
Genitalia The rich arterial supply to the vulva is from two external pudendal arteries and one internal pudendal artery on each side. The internal pudendal artery supplies the skin, sex organs, and the perineal muscles. The labial arteries are branches of the internal pudendal artery, as are the dorsal and deep arteries of the clitoris. Venous Drainage of the Female External
Genitalia The labial veins are tributaries of the internal pudendal veins and venae comitantes of the internal pudendal artery. Lymph Drainage of the Female External
Genitalia The vulva contains a very rich network of lymphatic channels. Most lymph vessels pass to the superficial inguinal lymph nodes and deep inguinal nodes. Innervation of the Female External
Genitalia The nerves to the vulva are branches of: 1. The ilioinguinal nerve; 2. The genital branch of the genitofemoral nerve; 3. The perineal branch of the femoral cutaneous nerve; 4. And the perineal nerve.The Female External Genital
Organs Click here for a schematic diagram of the female external genitalia. The Mons Pubis The mons (L. mountain) pubis is a rounded fatty elevation located anterior to the pubic symphysis and lower pubic region. It consists mainly of a pad of fatty connective tissue deep to the skin. The amount of fat increases during puberty and decreases after menopause. The mons pubis becomes covered with coarse pubic hairs during puberty, which also decrease after menopause. The typical female distribution of pubic hair has a horizontal superior limit across the pubic region. The Labia Majora The labia (L. large lips) are two symmetrical folds of skin, which provide protection for the urethral and vaginal orifices. These open into the vestibule of the vagina. Each labium majus, largely filled with subcutaneous fat, passes posteriorly from the mons pubis to about 2.5 cm from the anus. They are situated on each side of the pudendal cleft, which is the slit between the labia majora into which the vestibule of the vagina opens. The labia majora meet anteriorly at the anterior labial commissure. They do not join posteriorly but a transverse bridge of skin called the posterior labial commissure passes between them. The Labia Minora The labia minora (L. small lips) are thin, delicate folds of fat-free hairless skin. They are located between the labia majora. The labia minora contain a core of spongy tissue with many small blood vessels but no fat. The internal surface of each labium minus consists of thin skin and has the typical pink colour of a mucous
membrane. It contains many sensory nerve endings. Sebaceous and sweat glands open on both of their surfaces. The labia minora enclose the vestibule of the vagina and lie on each side of the orifices of the urethra and vagina. They meet just superior to the clitoris to form a fold of skin called the prepuce (clitoral hood). In young females the labia minora are
usually united posteriorly by a small fold of the skin, the frenulum of the labia minora. The Vestibule of the Vagina The vestibule (L. vestibulum,
antechamber) is the space between the labia minora. The urethra, vagina, and ducts of the greater vestibular glands open into the vestibule. Back to top The External Urethral Orifice This median aperture is located 2 to 3 cm posterior to the clitoris and immediately anterior to the vaginal orifice. On each side of this orifice are the openings of the ducts of the paraurethral glands (Skene's glands). These glands are homologous to the prostate in the male. The Vaginal Orifice This large opening is located inferior and posterior to the much smaller external urethral orifice. The size and appearance of the vaginal
orifice varies with the condition of the hymen (G. membrane), a thin fold of mucous membrane that surrounds the
vaginal orifice. The Greater Vestibular Glands These glands are about 0.5 cm in diameter. They are located on each side of the vestibule of the vagina , posterolateral to the vaginal orifice. They are round or oval in shape and the bulbs of the vestibule partly overlap them posteriorly. From the anterior parts of the glands, slender ducts pass deep to the bulbs of the vestibule and open into the vestibule of the vagina on each side of the vaginal orifice. These glands secrete a small amount of lubricating mucus into the vestibule of the vagina during sexual arousal. The greater vestibular glands (Bartholin's
glands) are homologous with the bulbourethral glands in the male. The Lesser Vestibular Glands These are small glands on each side of the vestibule of the vagina . They open into it between the urethral and vaginal orifices. These glands also secrete mucus into the vestibule, which moistens the labia and the vestibule. Back to top The Clitoris The clitoris is 2 to 3 cm in length. It is homologous with the penis and is an erectile organ. Unlike the penis, the clitoris is not traversed by the urethra; therefore it has no corpus spongiosum. The clitoris is located posterior to the anterior labial commissure, where the labia majora meet. It is usually hidden by the labia when it is flaccid. The clitoris consists of a root and a body that are composed of two crura, two corpora cavernosa, and a glans. It is suspended by a suspensory ligament. The parts of the labia minora passing anterior to the clitoris form the prepuce of the clitoris (homologous with the male prepuce). The parts of the labia passing posterior to the clitoris form the frenulum of the clitoris, which is homologous with the frenulum of the penile prepuce. The clitoris, like the penis, it will enlarge upon tactile stimulation, but it does not lengthen significantly. It is highly sensitive and very important in the sexual arousal of a female. The Bulbs of the Vestibule These are 2 large, elongated masses of erectile tissue that are about 3 cm in length. They lie along the sides of the vaginal orifice, deep to the bulbospongiosus muscles and are homologous with the bulb of the penis. Unlike the penis, however, the bulbs are separated from the clitoris and are separated by the vestibule of the vagina . Back to top Arterial Supply of the Female External
Genitalia The rich arterial supply to the vulva is from two external pudendal arteries and one internal pudendal artery on each side. The internal pudendal artery supplies the skin, sex organs, and the perineal muscles. The labial arteries are branches of the internal pudendal artery, as are the dorsal and deep arteries of the clitoris. Venous Drainage of the Female External
Genitalia The labial veins are tributaries of the internal pudendal veins and venae comitantes of the internal pudendal artery. Lymph Drainage of the Female External
Genitalia The vulva contains a very rich network of lymphatic channels. Most lymph vessels pass to the superficial inguinal lymph nodes and deep inguinal nodes. Innervation of the Female External
Genitalia The nerves to the vulva are branches of: 1. The ilioinguinal nerve; 2. The genital branch of the genitofemoral nerve; 3. The perineal branch of the femoral cutaneous nerve; 4. And the perineal nerve.

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