Q3_Module 2_The Feedback Mechanism in Menstrual Cycle

Q3_Module 2

The Feedback Mechanism in Menstrual Cycle

Multiple Choice

The ___________ is the hormonal process a woman's body goes through each month to prepare for a possible pregnancy.

• follicular phase

• menstrual cycle

• luteal phase

• ovulation

Multiple Select

Menstruation is the elimination of the thickened lining of the uterus (endometrium) from the body through the vagina.

• TRUE

• FALSE

Multiple Choice

Menstruation is a sign that a girl is ______________________.

• already pregnant

• capable of producing offspring

• no longer capable of becoming pregnant

• already menopaused

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Phases of the menstrual cycle

• The four main phases of the menstrual cycle are:

• a. menstruation

• b. the follicular phase

• c. ovulation

• d. the luteal phase.

The average length of the menstrual cycle is 28–29 days, but this can vary between women and from one cycle to the next. The length of your menstrual cycle is calculated from the first day of your period to the day before your next period starts.

Girls get their first period (menarche), on average, between the ages of 11 and 14 years. By this stage, other sexual characteristics have developed, such as pubic hair and budding breasts.

Menstruation

Menstruation is the elimination of the thickened lining of the uterus (endometrium) from the body through the vagina. The menstrual fluid contains blood, cells from the lining of the uterus (endometrial cells), and mucus. The average length of a period is between three days and one week.

Sanitary pads or tampons are used to absorb the menstrual flow. Both pads and tampons need to be changed regularly (at least every four hours). Using tampons has been associated with an increased risk of a rare illness called toxic shock syndrome (TSS).

Follicular phase

The follicular phase starts on the first day of menstruation and ends with ovulation. Prompted by the hypothalamus, the pituitary gland releases follicle-stimulating hormone (FSH). This hormone stimulates the ovary to produce around five to 20 follicles (tiny nodules or cysts), which bead on the surface.

Each follicle houses an immature egg. Usually, only one follicle will mature into an egg, while the others die. This can occur around day 10 of a 28-day cycle. The growth of the follicles stimulates the lining of the uterus to thicken in preparation for a possible pregnancy.

Ovulation

Ovulation is the release of a mature egg from the surface of the ovary. This usually occurs mid-cycle, around two weeks or so before menstruation starts.

Within two days, ovulation is triggered by the high levels of LH. The egg is funnelled into the fallopian tube and toward the uterus by waves of small, hair-like projections. The life span of the typical egg is only around 24 hours. Unless it meets a sperm during this time, it will die.

Luteal phase

The lining of the uterus called the endometrium becomes thicker in preparation for implantation of the fertilized egg. If fertilization takes place, the lining of the uterus stays in place. Likewise, no new eggs are released. If fertilization does not take place, menstruation happens. The next menstrual cycle is then about to begin. 

Multiple Choice

During this phase, the uterine lining begins to break down and bleeding results.

• Menstruation

• Follicular Phase

• Ovulation

• Luteal Phase

Multiple Choice

During this phase, follicle matures and endometrium develops.

• Menstruation

• Follicular Phase

• Ovulation

• Luteal Phase

Multiple Choice

During this phase, ovary releases an egg.

• Menstruation

• Follicular Phase

• Ovulation

• Luteal Phase

Multiple Choice

During this phase, the lining of the uterus called the endometrium becomes thicker in preparation for implantation of the fertilized egg.

• Menstruation

• Follicular Phase

• Ovulation

• Luteal Phase

POSITIVE FEEDBACK MECHANISM

In the positive feedback mechanism during the menstrual cycle, the rising levels of hormones feedback to increase hormone production. The following events happens: • The luteinizing hormone (LH) is produced by the pituitary gland. • The luteinizing hormone (LH) causes the follicle cells to make estrogen. • Estrogen promotes production of the luteinizing hormone (LH) • The luteinizing hormone (LH) produced increases. 

Multiple Choice

What happens to the hormones in a positive feedback mechanism?

• increases

• decreases

• do not change

• remain constant

NEGATIVE FEEDBACK MECHANISM 

In the negative feedback mechanism during the menstrual cycle, the response to a stimulus reduces that stimulus. Estrogen and progesterone provide negative feedback to the hypothalamus and pituitary gland during most of the menstrual cycle. This keeps their levels more or less constant. 

NEGATIVE FEEDBACK MECHANISM

These are the events that happens during the negative feedback mechanism in the menstrual cycle: • The luteinizing hormone (LH) is produced by the pituitary gland (stimulus) and promotes the formation of the corpus luteum. • The corpus luteum then produces progesterone as a response. • Progesterone inhibits the secretion of the luteinizing hormone (LH). 

Multiple Choice

What happens to the response to a stimulus in a negative feedback mechanism?

• increases that stimulus

• creates no changes in that stimulus

• reduces that stimulus

• makes the stimulus constant

Multiple Choice

What is the function of the follicle-stimulating hormone (FSH)in the menstrual cycle?

• promotes estrogen secretion from developing follicles

• stimulates ovulation

• inhibits FSH and LH for most of the cycle

• completes the development of the uterine wall

Multiple Choice

What is the function of the luteinizing hormone (LH) in the menstrual cycle?

• promotes estrogen secretion from developing follicles

• stimulates ovulation

• inhibits FSH and LH for most of the cycle

• completes the development of the uterine wall

Multiple Choice

Why is there limited cervical fluid mixed with blood in the vaginal discharge during the menstrual cycle?

• progesterone increases

• progesterone decreases

• estrogen increases

• estrogen decreases

Multiple Choice

What is the function of the luteinizing hormone (LH) in the menstrual cycle?

• promotes estrogen secretion from developing follicles

• stimulates ovulation

• inhibits FSH and LH for most of the cycle

• completes the development of the uterine wall