Urogenital Flashcards
Urogenital Development
Urinary and genital development are closely linked. Structures in one system are used in the other.
Kidneys
Urine forming organs. Maintain stable blood composition. Filters contents of blood. Excretes unneeded contents. Reabsorbs needed contents.
Kidney Formation Stages
Pronephros, Mesonephros, Metanephros
Pronephros
1st stage, non-functional in humans, mostly degenerates.
Mesonephros
2nd stage, temporarily functions as kidneys, doesn’t concentrate urine.
Mesonephric tubules
Short tubes that receive filtered blood and drain to mesonephric duct.
Mesonephric ducts
long tubes of the mesonephros. Drain to bladder.
metanephros
final stage. Concentrates urine (to conserve water), grows off of the mesonephros
primary sex determination
formation of the primary sex organs
Secondary sex determination
formation of th secondary sex organs. Promoted by hormones of primary sex organs
Gonadal ridge
bulge on mesonephros. Forms testes or ovaries. Y promotes testis.
Mesonephric tubules development
Either form rete testis and seminiferous tubules, or Degenerate into ovary
Mesonephric duct development
Degenerate in females, or become epididymus, ductus deferens, ejaculatory duct in males.
Paramesonephric duct development
degenerate in males if stimulated by Mullerian inhibiting substance (MIS), or form uterine tubes.
Indifferent external geitalia
external genitalia before secondary sex determination. Lack of testosterone forms female genitalia (ovaries not needed)
Effect of testosterone on indifferent external genitalia
Promotes development of male genitalia, causes testes to descend into scrotum, comes from testes.
Intersex conditions
conditions where sex of gonads does not match external genitalia.
types of intersex conditions
male pseudohermaphroditism (Androgen insensitivity syndrome (AIS)/testicular feminication syndrome), Female pseudohermaphroditism, true hermaphroditism
Male pseudohermaphroditism
A person with testes, but feminized genitalia. Caused my low testosterone and low MIS. Fetal testes produce insufficient amounts.
Degree of feminization of internal/external structures in male pseudohermaphroditism
Varies depending on the amount of testosterone and MIS produced
Female pseudohermaphroditism
A person with ovaries, but masculinized genitalia. Caused by excessive exposure to androgens (male sex hormone). Ovaries are normal, internal genitalia are usually feminine.
Female Pseudohermaphroditism abnormalities
Clitoris enlarges, Labia fuse.
True Hermaphroditism
A person with ovarian and testicular tissue. Both tissues may be in one organ, or in separate ones.(One ovary, one testis)
Ovotestis
An organ with both ovarian and testicular tissue.
Causes of true hermaphroditism
Pieces of Y-chromosome on an X-chromosome, fusion of early male and female embryos, Abnormal chromosomal seperation
True Hermaphroditism from y chromosome piece
x-chromosome inactivation causes some cells to use x-chromosome with y piece, and some to use a normal one.
True Hermaphroditism from early fusion
One embryo uses the cells of the other embryo (which kills one), Cells from the original male/female may be used for different gonads.
True Hermaphroditism from abnormal chromosomal seperation
Sperm delivers X and Y, only one X is copied, zygote divides into XX and XY.
True Hermaphroditism abnormalities
Gonads are usually nonfunctional, external genitalia are ambiguous
Androgen insensitivity Syndrome
A person with testes who appears externally female. Caused by insensitivity to testosterone. Production is normal, response to MIS is normal.
AIS abnormalities
Undescended, sterile testes, external female development(mammary glands, no womb or uterine tubes, no menstruation)
