Embryology of female genital organs
- 1. Embryology and Anatomy of female genital organs. SINGI
- 2. ORGANOGENESIS • It occurs from 4th to 8th week, • as the organs form , the embryo change its shape, and at 8th week it has a human appearance • The organs formed have minimal function except the cardiovascular system • During the 3rd month the external genitalia are developed, to be seen on echography by 12th week
- 3. Development of internal organs • The genital ridge arises from the intermediate mesoderm in the 4th week of embryonic life, • It remain undifferentiated until 7th week, • Ovarian determining gene, absence of SRY gene, and absence of testicular anti mullereian hormone, leads to formation of female gonads
- 4. • The undifferentiated gonad has the potential to become either a testis or an ovary, and hence is termed bipotential. • The fetus has two sets of structures called the Müllerian (or paramesonephric) ducts and Wolffian (or mesonephric) ducts, which have the potential to develop into male or female internal and external genitalia.
- 5. Ovary development • Yolk sack and allantois are the source of primordial germ cell, after their formation they migrate, invade the genital ridge at 6th week, if they don’t reach, gonads do not develop • the genital ridge project into a body cavity surrounded by wolffian and mullerian duct, At 7th week it separates from those ducts except at the hilum, At 3rd month the bulk of ovary is made up of cortex, a mass of crowded germ and epithelial cells, these cells divide and become oogonia By 8th month the ovary is attached to the body wall by mesovarium,
- 6. Development of follicles • In the primitive ovary granulosa cells, form primordial follicles. Each primordial follicle consists of an oocyte within a single layer of granulosa cells. • The maximum number of primordial follicles is reached at 20 weeks’ gestation when there are 6 to 7 million primordial follicles present. • The numbers of these reduce by atresia and at birth only 1–2 million remain. • Atresia continues throughout life and by menarche only 300,000–400,000 are present, and by menopause none. • The development of an oocyte within a primordial follicle is arrested at the prophase of its first meiotic division waiting atresia or meiotic process preceding ovulation
- 7. Formation of tubes, uterus, cervix, & upper vagina the absence of testicular AMH allows the Müllerian structures to develop the female reproductive tract develops from these paired ducts. The proximal two-thirds of the vagina develop from the paired Müllerian ducts, which grow in a caudal and medial direction and fuse in the midline. The midline fusion of these structures produces the uterus, cervix and upper vagina, the unfused caudal segments form the Fallopian tubes,
- 8. - Caudal ends turn medially, pass caudally side by side to reach urogenital sinus. - Each duct now formed of cranial & caudal vertical parts and middle horizontal part. • 2 caudal vertical parts fuse to form utero vaginal canal. • - Fallopian tubes develop from the 2 cranial vertical parts. • - Uterus develops from middle horizontal part & cranial part of utero vaginal canal. • - Vagina develops from 2 origins: upper 4/5 from caudal part of utero vaginal canal. lower 1/5 from urogenital sinus. The hymen is the junction in between.
- 9. Congenital malformations of the Uterus are due to abnormal fusion of mullerian duct A.Uterus didelphys: The uterus is entirely double and each one enters a separate vagina . B.Uterus arcuatus: slight indentation in the middle of the fundus of uterus. C. Uterus bicornis is one of the more common anomalies, for it there is a double-horned uterus entering a single vagina.
- 10. External female genitalia Between 5th & 7th weeks of life, the cloacal folds, swellings adjacent to the cloacal membrane, fuse anteriorly to become the genital tubercle. This will become the clitoris. The perineum develops and divides the cloacal membrane into an anterior urogenital membrane and a posterior anal membrane. • The cloacal folds anteriorly are called the urethral folds, and form the labia minora. • Another pair of cloacal folds form the labioscrotal folds that eventually become the labia majora. • The urogenital sinus becomes the vestibule of the vagina. • The external genitalia are recognizably female by the end of the 12th embryonic week.
- 13. • Mons pubis: fatty pad, covering pubic symphysis, covered by hairs after puberty, which is horizontal at upper border, • Role: contain sebaceous gland that release pheromones • Labia majora and labia minora: are folds of tissues extending from mons pubis to perenium, they protect the labia minora, urethral meatus, introitus • Critoris: it is the erectile, highly sensitive to touch, temperature, and pressure sensation • Vestibule is an oval shaped tissue connecting urethral meatus, vaginal introitus, and and baltholin glands secrete mucoid colorless secretions.
- 14. perenium • Diamond shaped - Ant.---Symphysis pubis - Post.---Coccyx - Lat. Ischial tuberosities & ischiopubic rami - Superficially-----skin - Deep-----pelvic diaphragm • Divided:By imaginary line between ischial tuberosities • 1- Urogenital triangle ---ant • 2- Anal triangle----------Post • Perineal body: in the center
- 15. Female Internal genital organs
- 17. Main arterial blood supply for internal genital organs
- 18. vagina Has 4 layers: mucosa, submucosa, muscalaris, adventitia • Has a mucosa composed of Non- keratinized St. Sq. Epith. • Has acidic pH 4-5 • It has No glands but release serous transudate • Blood Supply: 1- Vaginal a. from Int. iliac. 2- Branches ut. A, Int. pudendal, middle and inf. rectal.
- 19. uterus Anatomy: 1. Muscular, hollow, pear shaped 2. 1X2X3 inches 3. Body, cervix & isthmus Histology of body: • 1- Endometrium • 2- myometrium • 3- Perimetrium Blood supply • Uterine artery and branches from ovarian artery
- 20. Uterine ligaments • Uterine ligaments: • (1) Attached to body: - Round ligaments - Ovarian ligaments - Broad ligaments (2) Cervical ligaments: - Transverse (cardinal) - Uterosacral - Pubocervical - Uterus may have be: - AVF or RVF
- 21. FALLOPIAN TUBES Length: about 10 cm Divided into: Interstitial (intramural) Isthmus Ampulla Fimbria Blood supply: Branches from uterine and ovarian
- 22. ovary Size: 1 X 2 X 3 cm Functions of ovary: 1-Ova Production 2-Hormones (E2,Progesterone, androgen) • Blood supply: Ovarian (Aorta) & uterine a. Lymph drainage: Para-aortic LN.
- 24. reference • Human embryology and developmental biology lecture • 2017_Gynaecology_by_ten_teachers_20th_ed