4. platelet activation aggregation to form platelet plugs at the
site of injury
Thrombin a serine protease, converts soluble fibrinogen
into fibrin
Fibrin, aggregates with the platelet plugs and leads to the
cessation of bleeding by forming blood clots called thrombi
. Blood clots are prevented from accumulating during
menstruation by forming low amounts of platelet plugs
and synthesizing coagulation factor inhibitors that inhibit
blood coagulation.
Additionally, fibrinolysis is activated, during which
thrombus is broken down by a protease known as
plasmin.
7. Menstrual blood
• Menstrual blood is the product of menstruation in
menstruating women.
• On an average 35 ml of menstrual blood is secreted by
the female reproductive system during a single
menstruation cycle.
• Menstruation is the regular discharge of blood and
mucosal tissue from inner lining of the uterus.
• It must be noted that a woman starts menstruating
around 12-15 years of age (menarche) and stops
menstruating around 45-55 years of age (menopause).
• Menstrual blood differs from human circulatory blood in
terms of its content and its properties.
11. RNA based Assays
• Matrix metalloproteinase (MMP) genes are considered tissue-specific
markers for human endometrium tissues.
• MMPs are zinc-dependent endopeptidases that degrade extracellular matrix
components.
• The most commonly used markers for the forensic identification of menstrual
blood are MMP7 and MMP11
• Both MMP7 and MMP11 mRNA expressions are elevated at the menstrual
phase and remain at high levels during the proliferative phase.
• It is also known that MMPs’ mRNA may be elevated in postpartum, wound
healing, and metastatic cancer conditions, which may potentially lead to a
false-positive identification of menstrual blood.
Editor's Notes
The cessation of menstrual bleeding is achieved by endometrial hemostasis that is initiated when injury occurs due to the shedding of the endometrium
