The theca externa is the outer layer of the
theca folliculi. It is derived from connective tissue, the cells resembling
fibroblasts, and contains abundant
collagen.
During ovulation, the surge in
luteinizing hormone increases
cAMP which increases
progesterone and
PGF2α PGF may refer to:
* Paternal grandfather
* Patterson–Gimlin film, purporting to show Bigfoot
* IATA code of Perpignan–Rivesaltes Airport, France
* Placental growth factor, a human gene
* Vector graphics language in the PGF/TikZ pair
* Precisi ...
production. The PGF2α induces the contraction of the
smooth muscle
Smooth muscle is an involuntary non- striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit ...
cells of the theca externa, increasing intrafollicular pressure. This aids in rupture of the mature
oocyte
An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The femal ...
, or immature oocyte at the germinal vesicle stage in the canine, along with
plasmin
Plasmin is an important enzyme () present in blood that degrades many blood plasma proteins, including fibrin clots. The degradation of fibrin is termed fibrinolysis. In humans, the plasmin protein (in the zymogen form of plasminogen) is encode ...
and
collagenase degradation of the follicle wall.
References
External links
*
* - "Mammal, canine ovary (LM, High)"
* - "Mammal, bovine ovary (LM, Medium)"
* - externa
*
Slide at trinity.edu
Mammal female reproductive system
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