EMBRYOLOGY

1. EMBRYOLOGY LAB

2. Development and congenital anomalies of Genital Ducts

3. Uterine abnormalities arise from fusion malformations. Two uteruses and two vaginas (there was no fusion of the ducts at all.) Double uterus, one vagina( partial fusion).

5. Develoment and congenital anomaliesof gonads

6. Congenital malformations Agenesis of gonads: Externally, these individuals have the appearance of a female due to maternal estrogens.

7. Testicular feminization (androgen insensitivity syndrome): 46, XY, but are externally FEMALE; these individuals have testes but they are undescended. During embryonic life, the testis produced testosterone and paramesonephric duct inhibiting substance, so the paramesonephric duct failed to develop; thus, even though these individuals appear to be female, they have no uterus, no oviducts, and a blind ending vagina.

8. Testicular feminization (androgen insensitivity syndrome)

9. True hermaphrodite: • Has both testicular and ovarian tissue; usually the tissue is nonfunctional; can appear either as male or female; usually genetically female.

10. Pseudohermaphrodites have a normal chromosome pattern: 1. 46, XY: have variable internal and external genitalia; either an inadequate amount of testosterone and/or duct inhibiting hormone were produced or the tissues failed to respond to it.

11. Pseudohermaphrodites Males

12. 2. 46, XX: Usually a result of increased production of testosterone by the fetal adrenal gland, a condition termed congenital adrenal hyperplasia (due to an autosomal recessive gene); the excess testosterone causes masculinization of the external genitalia, such as clitorial hypertrophy and partial fusion of the labia majora; other causes of this condition include maternal ingestion/injection of testosterone or a testostrone secreting tumor.

13. Pseudohermaphrodites Female 16‐year‐old girl.

14. Pseudohermaphrodites Female A 13‐year‐old girl.

15. Development and congenital anomaliesof male & female external genitalia

16. A,B. Indifferent stages of the external genitalia. • A. Approximately 4 weeks. • B. Approximately 6 weeks. • C. In utero photograph of a 56-day embryo showing continued growth of the genital tubercle and elongation of the urethral folds that have not yet initiated fusion. The genital swellings remain indistinct.

17. A. Development of external genitalia in the male at 10 weeks. Note the deep urethral groove flanked by the urethral folds. B. Transverse sections through the phallus during formation of the penile urethra. The urogenital groove is bridged by the urethral folds. C. Development of the glandular portion of the penile urethra. D. Newborn.

18. Defects in the Male Genitalia: • In Hypospadias, fusion of the urethral folds is incomplete, and abnormal openings of the urethra occur along the inferior aspect of the penis, usually near the glans, along the shaft, or near the base of the penis. • If fusion of the urethral folds fails entirely, a wide sagittal slit is found along the entire length of the penis and the scrotum. The two scrotal swellings then closely resemble the labia majora. • Epispadias is a rare abnormality in which the urethral meatus is found on the dorsum of the penis. • Although epispadias may occur as an isolated defect, it is most often associated with exstrophy of the bladder.

19. A. Hypospadias showing the various locations of abnormal urethral orifices. • B. Patient with hypospadias. The urethra is open on the ventral surface of the penis. • C. Epispadias combined with exstrophy of the bladder. Bladder mucosa is exposed.

20. A. In utero photograph of the genitalia of a male fetus at 12 weeks. Note that the urethral folds are fusing and that the scrotal swellings are enlarging to merge in the midline. B. Genitalia of a female fetus at 11 weeks. Note that the urethral folds, which will become the labia minora, have not fused and that the genital swellings, that are forming the labia majora, are widely separated.

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