Physiology of Menstruation

Basilar arteries remain straight during the secretory phase, maintaining blood supply to the basal layer of the endometrium.

Cell death in endometrial layers, causing tissue shedding.

Superficial endometrial layers are shed during menstruation because of compromised blood supply affecting other layers.

Early phase of menstruation (days 1-4) characterized by blood, a thick hypoechoic central echo with a hyperechoic endometrial echo and posterior enhancement.

Late phase of menstruation (days 3-7), featuring a single hyperechoic thin line (central endometrial echo) and a hypoechoic halo.

Phase during menstrual cycle characterized by maximum endometrial thickness, hyperechoic endometrium, loss of halo, and maximum posterior enhancement.

Phase of the menstrual cycle (days 5-9) with a halo present, a relatively thin endometrium, and 6mm thickness.

Estrogen, from the Greek "Oistros" (frenzy; heat), is one of the key hormones in the menstrual cycle.

Progesterone, from the Greek "Pro" (in favor), "Gestare" (to bear), is another important hormone influencing the menstrual cycle.

A hormone crucial for sustaining a pregnancy in animals, present during the period when only coitus is possible.

A structure that produces a critical hormone for pregnancy.

A structure that plays a crucial role in maintaining pregnancy

A component of the placenta that produces hormones during pregnancy.

A source of a small amount of pregnancy hormone.

A source of a small amount of pregnancy hormone.

Another source of pregnancy hormones, found in the ovary.

The liver metabolizes the pregnancy hormone and excretes it in the bile and urine as preg-nandiol.

Blood levels show 2 peaks (one before and one after ovulation).

Shifting to a predominance of acidophilic cells with pyknotic nuclei on a clear background during pregnancy.

The cervix's mucous membrane changes from estrogenic to progestational during pregnancy.

Pregnancy hormone is mainly bound to proteins in the blood (like SHBG and albumin).

The endometrium, the lining of the uterus.

The inner lining of the uterus that thickens and sheds during the menstrual cycle.

Female sex hormones that regulate the endometrium.

Cyclic production of hormones (estrogen and progesterone) by the ovaries.

Pituitary hormone stimulating follicle development in the ovaries.

Pituitary hormone triggering ovulation and corpus luteum formation.

Hormone from the hypothalamus that controls FSH and LH release.

Disorders of the outflow tract (e.g., Mullerian agenesis, MRKH).

Disorders of the ovaries (e.g., gonadal dysgenesis).

A condition caused by intrauterine adhesions preventing endometrial proliferation and menstruation.

Scar tissue within the uterus.

Postpartum uterine curettage and severe uterine infections (e.g., tuberculosis).

Ischemic necrosis of the anterior pituitary, often due to severe postpartum hemorrhage.

Part of the pituitary gland affected in Sheehan's syndrome.

Genetic condition causing hypogonadotropic hypogonadism and anosmia.

Reduced production of hormones by the gonads.

Loss of the sense of smell.

Treatment used to stimulate endometrial regeneration.

Surgical procedure to break up intrauterine adhesions.

A genetic condition (45,X) characterized by the absence or malfunction of one X chromosome, often resulting in a lack of ovarian function.

A condition (46,XX) characterized by the absence or underdevelopment of the ovarian structures and/or a complete lack of ovarian function.

A condition (46,XY) where the gonads are underdeveloped or absent, leading to the development of female secondary sexual characteristics.

A condition also known as resistant ovary syndrome, characterized by an inability of ovaries to respond to stimulating hormones.

A tumor in the anterior pituitary that produces prolactin, a hormone that can cause irregular menstruation.

A tumor that develops near the pituitary gland, which may impact hormone production.

A condition where the pituitary gland doesn't produce enough hormones to stimulate the gonads (ovaries/testes).

A condition where the ovaries/testes don't respond to hormones that stimulate them.

Absence of menstruation by age 14 with no development of secondary sexual characteristics or by age 16 with secondary characteristics.

Absence of menstruation for three or more cycles or for 3-6 months.

Scar tissue in the uterus (endometrium) preventing normal menstrual flow.

Absence of menstruation.

Absence of menstruation by age 16 (with normal secondary sex characteristics) or age 14 (without secondary sex characteristics).

Absence of menstruation for 6 months or more, or equivalent to 3 missed cycles, in a previously menstruating woman.

Hormone crucial in maintaining a pregnancy.

The organ sustaining the developing fetus during pregnancy.

Normal absence of menstruation, e.g., pregnancy, breastfeeding, pre-puberty, menopause.

Hidden menstruation; periods occur but the flow isn't expelled.