MENSTRUAL CYCLE

Hormone• A Hormone is a chemical released by a cell or a

gland in one part of the body that sends out messages that affect cells in other parts of the organism.

• Hormones are released in a very small amount.• Endocrine Hormones are secreted (released)

directly into the bloodstream, whereas Exocrine Hormones (or ectohormones) are secreted directly into a duct, and, from the duct, they flow either into the bloodstream or from cell to cell by diffusion in a process known as paracrine signalling.

HYPOTHALAMUS• The Hypothalamus is a portion of the brain that contains

a number of small nuclei with a variety of functions. • One of the most important functions of the

hypothalamus is to link the nervous system to the endocrine system via the pituitary gland.

• It synthesizes and secretes certain neurohormones, often called hypothalamic-releasing hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones.

• The hypothalamus controls body temperature, hunger, thirst, fatigue, sleep, and circadian cycles.

• Pituitary Gland, is an endocrine gland about the size of a pea and weighing 0.5 gm.

• Also called “Master Gland”.• It secretes variety of hormones, which stimulate the

other endocrine glands to secrete their own hormones.

• Pituitary gland functions under the control of Hypothalamus.

• The pituitary gland is functionally linked to the hypothalamus by the Pituitary Stalk

PITUITARY GLAND

• Anterior Pituitary Gland synthesizes and releases following Gonadotropins- Follicle Stimulating Hormone (FSH)- Lutenizing Hormone (LH)

• Both of these hormones are released under influence of Gonadotropin Releasing Hormone (GnRH) from Hypothalamus

PITUITARY GLAND

• Also called FSH• FSH regulates the development, growth, pubertal

maturation, and reproductive processes of the body.• FSH and Luteinizing Hormone (LH) act synergistically in

reproduction.• In females, FSH initiates follicular growth.• Decline in FSH levels during late follicular phase seems to

be critical in selecting only the most advanced follicle to proceed to ovulation.

• At the end of the luteal phase, there is a slight rise in FSH that seems to be of importance to start the next ovulatory cycle.

FOLLICLE STIMULATING HORMONE

• Also called LH or Lutropin• In females, an acute rise of LH called the LH surge

triggers ovulation and development of the corpus luteum.

• LH is necessary to maintain luteal function for the first two weeks.

• In case of a pregnancy luteal function will be further maintained by the action of hCG (a hormone very similar to LH) from the newly established pregnancy.

LUTEINIZING HORMONE

• The three major naturally occurring estrogens in women are estrone (E1), Estradiol (E2), and Estriol (E3).

• Estradiol (E2) is the predominant form in nonpregnant females, Estrone (E1) is produced during menopause, and Estriol (E3) is the primary estrogen of pregnancy.

• Estradiol levels vary through the menstrual cycle, with levels highest just before ovulation.

• Estrogens are produced primarily by developing follicles in the ovaries.

• Luteinizing Hormone (LH) stimulates the production of estrogen in the ovaries.

ESTROGENS

• Promote formation of female secondary sex characteristics

• Reduce muscle mass • Stimulate endometrial growth • Increase uterine growth • Increase vaginal lubrication • Thicken the vaginal wall • Maintenance of vessel and skin • Reduce bone resorption • Increase bone formation

Role of ESTROGENS

• "Pro" means "for" and “gesterone” means "gestation". • Gestation is the carrying of an embryo or fetus inside the

Uterus.• Progesterone is sometimes called the “Hormone of

Pregnancy“• Progesterone converts the Endometrium to its secretory

stage to prepare the uterus for implantation. At the same time Progesterone affects the Vaginal Epithelium and Cervical Mucus, making it thick and impenetrable to sperm.

PROGESTERONE

• If the egg is fertilized (Pregnancy occurs), the Corpus Luteum will begin receiving hCG from the embryo. hCG tells the Corpus Luteum to keep producing Progesterone.

• If pregnancy does not occur, Progesterone levels will decrease, leading to Menstruation. Normal Menstrual Bleeding is Progesterone-withdrawal Bleeding.

PROGESTERONE

• also called hCG• hCG is a glycoprotein hormone produced in

pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast (part of the placenta).

• Its role is to prevent the disintegration of the corpus luteum of the ovary and thereby maintain progesterone production that is critical for a pregnancy.

• Early pregnancy testing, in general, is based on the detection of hCG.

HUMAN CHORIONIC GONADOTROPIN

• Menstruation is the periodic discharge of blood and sloughed endometrium (collectively called menses or menstrual flow) through the vagina.

• Menstruation occurs throughout a woman's reproductive life in the absence of pregnancy.

• The average Menstrual Cycle length is 28 days (usual range, about 25 to 36 days).

• Average duration of menses is 5 (± 2) days. • Blood loss per cycle averages 30 mL (normal range,

13 to 80 mL) and is usually greatest on the 2nd day.

MENSTRUAL CYCLE

• Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings.

• The average age of menarche is 11.75 years.• Menopause is the permanent cessation of

menses.• Menopause typically (but not always) occurs in

women during their late 40s or early 50s, and signals the end of the fertile phase of a woman's life.

MENSTRUAL CYCLE

• The Menstrual Cycle can be divided into 3 Phases.- Follicular (Preovulatory) Phase- Ovulatory Phase- Luteal (Postovulatory) Phase

MENSTRUAL CYCLE

Follicular PhaseDay 1-13

During this Phase ovary also secretes increasing level of

Estrogen, to initiate Endometrium

Pituitary gland produces FSH (Follicular Stimulating Hormone)

FSH act on ovary for prompt development of several follicles

(Each Follicle Contains Egg)

During this phase one follicle mature

Hypothalamus releases GnRF which stimulates release of LH and FSH from Anterior Pituatary

Ovulatory Phase Lasts for 16 to 32 hours

Phase begins when the level of LH surges.

LH stimulates dominant follicle to bulge from the surface of ovary and finally rupture, releasing the Egg.

Egg travel to Fallopian Tube. This is the time when the women is most likely to become Pregnant. The Egg can be

fertilized for only up to about 12 hours after its release.

Luteal Phase, Day 15-28

After releasing Egg this empty Follicle develops the structure called Corpus Luteum (CL)

CL secrets increasing amount of Progesterone. CL prepares Uterus in case fertilization occurs.

Progesterone causes the Endometrium to thicken

If Egg is Fertilized If Egg is not Fertilized

CL destroys after 14 days an new Menstrual Cycle

begins

The embryo produces Human Chorionic Gonadotropin (hCG) which will be detected by CL and this Human Chorionic Gonadotropin maintains CL and its Progesterone secretion.

The egg moves to the uterus and attaches itself to the endometrium about six or seven days after ovulation,

where it begins to develop into a fetus.

AmenorrheaAmenorrhea is the absence of a menstrual period in a woman of reproductive age.

Primary AmenorrheaPrimary Amenorrhea is the absence of menstruation in a woman by the age of 16.

Secondary AmenorrheaSecondary Amenorrhea is where an established menstruation has ceased—for 3 months in a woman with a history of regular cyclic bleeding, or 9 months in a woman with a history of irregular periods.

MENSTRUAL DISORDERS

DysmenorrheaDysmenorrhea is a gynecological medical condition characterized by severe uterine pain during menstruation.

Menorrhagia/HypermenorrheaMenorrhagia is an unusually heavy and prolonged menstrual period at regular intervals.A blood loss of greater than 80 ml or lasting longer than 7 days constitutes menorrhagia

HypomenorrheaHypomenorrhea is extremely light menstrual blood flow (scanty periods).

MENSTRUAL DISORDERS

MetrorrhagiaMetrorrhagia is uterine bleeding at frequent, irregular intervals, particularly between the expected menstrual periods.

MenometrorrhagiaMenometrorrhagia is a condition in which prolonged or excessive uterine bleeding occurs irregularly and more frequently than normal.

PolymenorrheaPolymenorrhea is the medical term for cycles with intervals of 21 days or fewer.

OligomenorrheaOligomenorrhea is infrequent (or very light) menstruation. More strictly, it is menstrual periods occurring at intervals of greater than 35 days.

MENSTRUAL DISORDERS

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