Roles of Hormones in

Menstrual Cycle .By : Zulaikha Faudzi .

Puberty .

The period which marks the beginning of maturity in both males and females .

Changes for females :

o Breast development

o Pubic and underarm hair

o Growth spurt and body shape change

o Vaginal discharge

o Skin ( oilier , acne )

o Perspiration ( body odor )

o Menstruation .

Changes for males .

o Pubic hair

o Growth spurt

o Voice change

o Body hair ( face , underarm )

o Acne

Menstrual Cycle .

Monthly cycle of changes that occurs in the female body .

Associated with ovulation and discharge of blood .

Each cycles : 28 days .

It is important for : (a) To prepare the uterus

for the implantation of

a zygote .

(b) Occurrence of ovulation

(c) Occurrence of

menstruation

(d) To stimulate the

secretions of various

hormones .

Menstruation .

Discharge of blood and tissues of the endometrium when the uterine lining breaks down during the menstrual cycle .

Normally lasts for about 4 to 5 days .

Changes in the ovary during menstrual cycle .

Changes in the ovary associated with

development of follicles and ovulation .

Changes in the thickness of the lining of the uterus .

Changes in the levels of hormones involved in the menstrual cycle .

Importance of Menstrual Cycle .

To prepare the uterus for the implantation of a zygote .

During the menstrual cycle , the lining of the uterus becomes progressively thicker with more blood vessels .This prepares the uterus for implantation of a fertilisedegg ( zygote ) .

Occurrence of ovulation . Follicles in the ovary develop to become a mature

Graafian follicle .

The secondary oocyte in the Graafian follicle is the released from the ovary about halfway through a menstrual cycle , approximately on the 14th day .

The secondary oocyte is collected by the Fallopian tube if sperms are present .

Occurrence of Menstruation . If the secondary oocyte is not fertilised , it begins to

break down is discharged .

The uterine lining also breaks down and sloughs off .

The blood and the discarded tissue of uterine will be discharged from the body through the vagina .

( Menstruation )

To stimulate the secretions of various hormones

There are four types of hormones involved in the menstrual cycle :

o Follicle stimulating hormone ( FSH )

o Luteinising hormone ( LH )

o Oestrogen

o Progesterone

Secreted by pituitary gland

Secreted by ovary

Roles of Hormones in Regulating the

Menstrual Cycle .

Menstrual Cycle can be divided into three stages .

I. Menstruation stage ( 1st day to 5th day )

II. Follicle development ( 6th to 14th day )

III. Corpus luteum stage ( 15th day to 28th day )

The diagram shows the three stages of menstrual cycle and the relationship between hormonal levels with the development of follicles , ovulation , formation of corpus luteum and changes in thickness of the endometrium .

Menstruation stage Progesterone level is at its lowest .

The endometrium of the uterus breaks down and sloughs off . The discarded tissue of endometrium together with blood is discharged . Menstruation begins .

During menstruation , the pituitary gland is stimulated to secrete Follicle Stimulating Hormones ( FSH) which stimulates the development of follicles .

• Follicle development stage Primary follicle in the ovary develops into a Graafian

follicle .

The development of follicles in the ovary stimulates the secretion of oestrogen .

Oestrogen repairs the uterine wall and causes the endometrium to thicken in preparation for implantation .

When the level of oestrogen increases and reaches a particular level , it stimulates the pituitary gland to secrete luteinising hormone ( LH ) . At the same time , it stops the pituitary gland from producing FSH causing the of FSH become lower .

LH causes ovulation on the 14th day . A secondary oocyte is released from the Graafian follicle .

Corpus luteum stage The Graafian follicle that remains in the ovary after

ovulation will form a corpus luteum .

The remaining follicle cells in the ovary continue to release oestrogen . This causes a slight increase in the oestrogen level after ovulation . The corpus luteumsecretes progesterone .

Progesterone thickens the endometrium and stimulates more blood vessels to develop in it . The thick endometrium is ready for implantation of fertilised egg .

If fertilisation occurs . The corpus luteum remains and continues to secrete

progesterone that will maintain the thickness of the endometrium .

Progesterone also inhibits the secretion of FSH and LH , thus preventing further development of follicles and ovulation during pregnancy .

If fertilisation does not occur . The corpus luteum will degenerate .

Progesterone level and oestrogen level become lower .

The endometrium of the uterus begins to to break down slough off , resulting in menstruation .

Effects of Hormonal Imbalances in

the Menstrual Cycle on Woman .

Premenstrual Syndrome ( PMS ) A combination of physical and emotional symptoms

that are related to the menstrual cycle .

Occurs in the week before menstruation starts .

May effect woman emotionally , mentally and physically .

o Irritability

o Tension

o Depression

o Confusion

o Anxiety

o Oversensitivity

o Mood swings

o Low self-esteem

o Lack of concentration

Common emotional and mental symptoms

o Headaches

o Fatigue

o Feeling bloated

o Breast tenderness

o Abdominal pain

o Sleep disturbances

o Appetite changes

Miscarriage Progesterone maintains the thickness of the

endometrium for implantation of a zygote.

Failure in the production of progesterone cause the thickness of the endometrium to be reduced .

The embryo cannot be embedded securely in the endometrium .

Miscarriage occurs .

Physical symptoms

Menopause Occur between the ages of 45 and 55 .

The ovary becomes inactive and stops producing ovum .

Less FSH and LH is produced .

The ovaries produce less progesterone and oestrogendue to the limited development of follicles .

Ovulation and the menstrual cycle become irregular and finally stop .

A woman is said to have reached menopause when she has not had menstruation for 12 months in a row .

o Hot flushes

o Night sweats

o Sleeping disorders

o Osteoporosis

o Mood changes

o Weight gain

o Hair loss

Symptoms woman may experience due to the changes in hormone levels

Summary .

Day 1-5 Hormone : Follicle stimulating hormone ( FSH )

Hormone level : FSH increase .

Follicle development : FSH develops the

development of one primary

oocyte .

Thickness of endometrium : Endometrium of

uterus breaks down .

Day 6-14 Hormone : (i) FSH

(ii) Oestrogen

(iii) Luteininsing hormone ( LH )

Hormone level : (i) FSH continues to increase until

the 6th day and then stops .

(ii) FSH stimulates the ovary to

secrete oestrogen . The level

oestrogen increases until 12th

day . The high level of oestrogen

stimulates the secretion of LH .

(iii) The level of LH begins to

increase on the 10th day until

the 14th day .

Follicle development : (i) The follicle continues to

develop until it becomes a

matured Graafian follicle .

Follicle development : (ii) The matured Graafian

follicle bursts on the 14th

day and releases the

secondary oocyte . The

remaining Graafian follicle in

the ovary becomes the

corpus luteum .

Thickness of endometrium : Oestrogen repairs and the

thickens the endometrium .

Day 14-28 Hormone : Progesterone .

Hormone level : The level of progesterone begins to

increase on the 14th day until the

25th day . Then it begins to decrease

as progesterone inhibits the

secretion of FSH and LH .

Follicle development : Corpus luteum remains but

begins to degenerate on the

25th day if fertilisation does

not occur .

The thickness of endometrium : Maintained until

the 25th day if

fertilisation does

not occur .