Embryology of the Gonads Flashcards
what is the genetic sex determined by
sperm
what is the SRY
sex-determining region of the Y chromosome
it is a gene which initiates the production of testis determine factor
what happens if there is no chromosome Y in sperm
no Y = no TDF - female development commences
what is the reproductive and urinary system derived from
intermediate mesoderm
urogenital ridge
then into the two separate systems
what weeks do the male and female gonads differentiate
weeks 5-6
what specifically forms the primitive sex cords
epithelium covering the urogenital ridge proliferates and penetrates the underlying mesoderm
what happens in week six in forming the genitalia
primordial cells migrate to genital ridge
what does the indifferent gonad be split into
outer cortex and inner medulla
what is the fate of medullary and cortical region dependant on
TDF production
what are the difference in structures of developing male and female gonads
cortical cords
medullary cords
tunica albuginea
cc - develop in female but none in male
mc - develop in males but regress in females
ta - develop in males, no development tin females
what do the medullary cords in the testis turn into
rete testis (hilum) seminiferous tubules
what is the tunica albuginea
in the 4th month it is a connective tissue that develops around the testes
what happens to development of the ovary between 7th week and 5th month
medullary cords degenerate
surface epithelium continues to proliferate and produces second generation cords - cortical cords
cortical cords split and surround oocytes
all oocytes are present at birth
at what week is the male and female gonad distinguishable
week 7
describe the start of the descent of the testes from the posterior abdominal wall in weeks 7-12
extrabdominal gubernaculum shortens pulling testis towards the anterior abdominal wall where they arrive at the internal inguinal ring from 3rd to 7th month
what happens after 7 months of pregnancy to the descent of the testes
gubernaculum shortens again pulling them through inguinal canal of abdominal wall - aided by pressure of growing organs
testes reach scrotum by 9th month just before birth
what happens within the first year of fetal growth to the processes vaginalis
obliterates leaving a remnant round the testes known as the tunica vaginalis
what are the 3 muscles of the inguinal wall
transverses abdominus (and fascia ) internal / external oblique
what is the deep and superficial ring of the lingual canal
deep - entrance of inguinal canal and is located in transversals fascia
superficial - exit of inguinal canal and is located in external oblique
what are the coverings of the testes and where are they from
internally
internal spermatic fascia - from transversalis fascia
cremasteric fascia - from internal oblique muscle
external spermatic fasica - from external oblique muscle
what is a patent processes vaginalis and what are the clinical consequences
parts of the processes vaginalis may remain unfused leaving small cyst
cysts can produce fluid and swell - hydrocele
can be surgically removed
if the processes vaginalis remains open to abdominal cavity intestines may protrude through inguinal canal - indirect inguinal hernia
what is transillumination in hydrocele
formed by clear fluid and therefore light can pass through it
if it were a hernia aor tumour light would be blocked by it
what is cryptorchidism
affects 1-4% broths but most correct themselves at 3 months of age
undescended testicles - can be surgically corrected at 4-6 months
what is cryptorchidism associated with
increased risk of testicular cancer and infertility
