WEEK 5: MENSTRUAL CYCLE

Question 1

how long does menstrual cycle last?

Answer 1

mean 28days
Range: 21-35 days

Question 2

How much is the normal menstrual flow?

Answer 2

35ml of blood together with 35ml of serous fluid

Question 3

How long does menstruation last?

Answer 3

3-8 days

Question 4

What is the first menstruation called?
At what age does it usually starts?

Answer 4

Menarche
10-15 years

Question 5

What is the menstrual cycle?

Answer 5

The menstrual cycle is the monthly series of changes a woman’s body goes through in preparation for the possibility of pregnancy.

Question 6

What is an ovarian cycle?

Answer 6

The ovarian cycle is a series of events that occur during the menstrual cycle, such as follicle development, ovulation, and corpus luteum formation. It occurs in the cortex of the ovaries.

Question 7

What is oogenesis?

Answer 7

The process of formation of female gametes (ova)

Question 8

state 3 phases of the ovarian cycle

Answer 8

follicular phase
ovulation
luteal phase

Question 9

State the 3 stages of menstrual cycle

Answer 9

Menstrual phase, proliferative phase and secretory phase

Question 9

State the physiological changes that occur during menstrual cycle

Answer 9

*Ovarian phase [follicular, ovulation, luteal]
*uterine phase [menstrual, proliferation, secretory/ progestational]
*vaginal changes
*cervical changes
*breast changes

Question 10

What is the other name for primordial cell?

Answer 10

oogonium

Question 11

Briefly describe the process of oogenesis, (follicular phase of the ovarian and menstrual cycle)

Answer 11

1.One is born with stem cells called oogonium
2.The oogonium undergoes mitotic division forming Primary oocyte.
3.The primary oocyte is starts meiosis I and freezes at Prophase I [before birth]
*There is production of the Gonadotropin releasing hormone by the hypothalamus which will act on the gonadotropes in the anterior pituitary gland and result in the release of the FSH and LH
* The primary oocyte finishes meiosis I and form a haploid secondary oocyte and the first polar body ( after puberty)
*The secondary oocyte undergoes meiosis II and freezes at metaphase II
*After fertilization, the secondary oocyte forms and ootid and the secondary polar body
*The polar bodies detach from the ootid which is now called a MATURE OVUM

Question 12

What happens to the oogonia that were not converted to primary oocytes?

Answer 12

They undergo self destruction by apoptosis (cell suicide)

Question 13

Compare spermatogenesis and oogenesis

Answer 13

S:The production of sperms from spermatogonia is known as spermatogenesis
O:The production of eggs from oogonia is known as oogenesis

S:Occurs in testes
O:Occurs inside the ovary

S:All stages are completed in testes
O:The major part of oogenesis occurs inside the ovary
The last few stages occur in the oviduct

S:.It is a continuous process
O:It is a discontinuous process. The early stages take place in the foetus and the rest in later stages of life.

S:Produces motile gametes
O:Produces non-motile gametes

S:Equal cytokinesis occurs during the spermatogenesis producing four sperms
O:Unequal cytokinesis occurs during oogenesis

Question 14

Describe the follicular phase of the ovarian cycle

Answer 14

*a primary oocyte is surrounded by granulosa cells forming a primary follicle
*Under the influence of local paracrines, granulosa cells proliferate to form the zona Pellucida around the oocyte
*surrounding ovarian tissue differentiates into thecal cells, converting a primary follicle into a pre antral follicle ( early secondary follicle)
* Pre antral follicles are recruited for further development under the influence of FSH. The hormonal environment promotes rapid enlargement of and development of the recruited pre antral follicles which are converted to antral follicles ( secondary follicles)
*During this stage,an antrum forms in the middle of granulosa cells.
* The follicular cells starts secreting and producing estrogen.
*Some of the estrogen accumulates in the antral fluid
*The oocyte has reached full size by the time the antrum forms.
* There is rapid growth of follicles
* The follicle with most FSH receptors will be responsive mostly to the hormonal stimulation and proliferate more than the others making it a “dominant follicle”
*The dominant follicle forms a mature follicle called Graafian follicles/ tertiary follicles / preovulatory follicle

Question 15

Describe a mature follicle

Answer 15

Has the most FSH receptors
The antrum occupies most of the space
The oocyte is asymetrically displaced at one side of the growing follicle in a little mould that protrudes into the antrum

Question 16

Describe ovulation

Answer 16

The greatly expanded mature follicle bulges on the ovarian surface, creating a thin area that ruptures to release the secondary oocyte.Rupture of the follicle is facilitated by the burst in LH secretion which digest the connective tissue in the follicular wall

Question 17

Describe the luteal phase of ovarian cycle

Answer 17

The ruptured follicle develops into a corpus luteum under the influence of Luteinizing hormone. The corpus luteum continues to grow and secrete progesterone and estrogen that prepare the uterus for implantation of a fertilized ovum

After 14 days, if a fertilized ovum does not implant in the uterus, the corpus luteum degenerates, and are phagocytized, and a connective tissue rapidly fills in to form a fibrous tissue called corpus albicans

The luteal phase ends and a new

Question 18

Describe how estrogen is produced by the ovarian follicle to be used to promote antral formation

Answer 18

1.Release of GnRH from the hypothalamus
2.Stimulates release of FSH and LH
3.LH acts on the theca cells which convert Cholesterol to Androgen
4.Granulosa cells are acted on by FSH which result in formation of aromatase enzyme
5.Aromatase converts Androgen into estrogen
6.Estrogen is secreted into blood where it exerts effects throughout the body
7.Some remain in the follicle and contributes to antral formation
8.The follicles to grow and produce more estrogen as more estrogen follicular cells are present
9.A negative feedback mechanism is induced on the hypothalamus and directly on the pituitary gland to reduce FSH release.
10.A hormone INHIBIN produced by granulosa cells also inhibits the FSH secretion by acting on the anterior pituitary gland

So in the follicular region, the LH increases as estrogen increase while the FSH decrease

Question 19

How long does an ovum survive for after ovulation?

Answer 19

12-24 hrs

Question 20

How long does a sperm survive for after ejaculation?

Answer 20

3-5 days

Question 21

What produces the inhibin hormone that inhibits secretion of FSH?

Answer 21

Granulosa cells

Question 22

Which cells are acted on by LH which activate them to produce Androgen from Cholesterol?

Answer 22

Theca cells ( theca interna)

Question 23

What enzyme convert Androgen to estrogen?

Answer 23

Aromatase

Question 24

What is the function of estrogen in follicular phase?

Answer 24

Contributes to antral formation

Question 25

Which part in the maturation of the ovarian follicle requires estrogen?

Answer 25

The further development and antral formation

Question 26

What forms the theca cells layer in an ovarian follicle?

Answer 26

Surrounding ovarian tissue

Question 27

When does ovulation occur?

Answer 27

Mid-cycle
usually at day 14

Question 28

What is corona radiata?

Answer 28

The corona radiata isan outer layer of follicular (granulosa) cells that form around a developing oocyte in the ovary and remain with it upon ovulation

Question 29

Describe the menstrual phase

Answer 29

• discharge of blood and endometrial debris from the vagina
• First day of menstrual cycle coincides with the end of the ovarian luteal phase and onset of a new follicular phase

*As the corpus luteum degenerates after failure of fertilization and implantation from the previous cycle

*Progesterone and estrogen levels decrease

*Withdrawal of these hormones deprives the highly vascular , nutrient rich uterine lining of its hormonal support

*The fall of these hormones also stimulates release of uterine PROSTAGLANDIN that causes vasoconstriction of the endrometrial vessels, disrupting the blood supply to the endometrium

*the subsequent reduction of Oxygen delivery causes death of the endometrium including its blood vessels

*The distal arteries are sloughed off while the spiral arteries retract into the Stratus basalis and constrict to limit blood loss. They extend again when the Stratum functionalis reforms

*The resulting bleeding through the disintegrating vessels flushes the dying endometrial tissue into the lumen of the uterus

*The local UTERINE PROSTAGLANDIN also stimulates the mild and rythmic contractions of the myometrium.

*These contractions expel blood and the endometrial debris from the uterine cavity through the vagina as MENSTRUAL FLOW

The drop in gonadal hormones secretion removes inhibitory influences from the hypothalamus and the anterior pituitary gland , so FSH and LH secretion increases and a new follicular phase begins . After 5 to 7 days under the influence of FSH and LH, the newly growing follicles are secreting enough estrogen to promote repair and growth of the endometrium

NEXT, PROLIFERATIVE PHASE

Question 30

Name the substance produced to dissolve endometrium clots

Answer 30

fibrinolysin

Question 31

What term is used to refer to menstrual cramps?

Answer 31

dysmenorrhea

Question 32

Outline the functions of UTERINE PROSTAGLANDIN in menstrual phase

Answer 32

*Causes vasoconstriction of the endometrial vessels, restricting blood supply to the endometrium
*Stimulates mild and rythmic contractions of the myometrium

Question 33

Describe the proliferative phase

Answer 33

Menstrual cycle ceases, The production of the estrogen from the last portion of the ovarian follicular phase starts the formation of the endometrium as it starts to repair itself and repair itself under the influence of the newly growing follicles.
The estrogen stimulates proliferation of epithelial cells, glands and blood vessels in the endometrium increasing its epithelial thickness from 1mm to 3-5mm.

*The estrogen dominant proliferation phase lasts from the end of menstruation to ovulation [Day 8-14]

NEXT, SECRETORY OR PROGESTATIONAL PHASE

Question 34

Describe the progestational or secretory phase

Answer 34

*It coincides with the ovarian luteal phase
*After ovulation, when a corpus luteum is formed, the uterus enters into the secretory or progestational phase.
*The corpus luteum secretes large amounts of progesterone and estrogen
*Progesterone converts the thickened , estrogen primed endometrium to a richly vascularized , glycogen filled tissue.

*This period is called secretory phase because the endometrial glands are actively secreting glycogen into the uterine lumen for early nourishment oaf a developing embryo before it implants, or the progestational ( before pregnancy) phase referring to the development of a lush endometrial lining capable of supporting and embryo after implantation

• If pregnancy does not occur, the corpus luteum undergoes luteolysis under the influence of estradiol and prostaglandins and forms a scar tissue called the corpus albicans

NEXT, EVENTS LEADING TO MENSTRUATION

Question 35

State the components found in menstrual flow

Answer 35

blood, endometrial debris and some leukocytes

Question 36

What is menopause?

Answer 36

Menopause is the time that marks the end of your menstrual cycles.
It’s diagnosed after you’ve gone 12 months without a menstrual period.

Question 37

What is climacteric or perimenopause?

Answer 37

The period from sexual maturity to cessation of reproductive capability

Question 38

Why are post menstrual women not completely devoid of estrogen?

Answer 38

Because the adipose tissue , the liver and the adrenal cortex continue to produce up to 20mg of estrogen per day.

Question 39

Outline how long each of the stages of ovarian cycle takes

Answer 39

*follicular phase: Day 1-14
*luteal phase: Day 15-28
* Ovulation: Day 14

Question 40

Outline signs and symptoms of menopause and how they come about?

Answer 40

*HOT FLASHES: Estrogen helps modulate the actions of epinephrine and norepinephrine on the arteriolar walls by promoting a vasodilator nitric oxide. Low estrogen in menopause results in unstable control of blood flow , especially in skin vessels. Transient increases in the flow of warm blood through these superficial vessels are responsible for the blood “hot flashes “ that usually accompanies menopause

*IRREGULAR CYCLES: hormonal imbalances and dwindling of estrogen levels

*BONE FRACTURES INCIDENCE: Estrogen controls the balance between osteoblasts and osteoclasts, avoiding osteoporosis.
Low levels of ovarian estrogen diminishes activity of bone building of osteoblasts and increases activity of bone dissolving osteoclasts which result in low bone density
*INSOMNIA
*vaginal dryness leading to discomfort during sex
*Gradual atrophy of the genital organs

Question 41

Describe the physiology of menopause

Answer 41

censure of ovulation due to depletion of all the follicles in the ovary
*Low or no maturation of the follicles in early menopause results in low estrogen levels. There is excessive release of FSH stimulation .Excess FSH

Question 42

Outline how long each of the phases of the uterine phase takes

Answer 42

Menstrual phase: 1-5
Proliferation phase: 6-14
Progestational / secretory phase: 15-28

Question 43

What is amenorrhoea?

Answer 43

Amenorrhea (uh-men-o-REE-uh) is the absence of menstruation, often defined as missing one or more menstrual periods

Question 44

Define primary and secondary amenorrhoea

Answer 44

Primary amenorrhea refers to the absence of menstruation in someone who has not had a period by age 15. The most common causes of primary amenorrhea relate to hormone levels, although anatomical problems also can cause amenorrhea.

Secondary amenorrhea refers to the absence of three or more periods in a row by someone who has had periods in the past. Pregnancy is the most common cause of secondary amenorrhea, although problems with hormones also can cause secondary amenorrhea.

Question 45

State the possible causes of amenorrhoea?

Answer 45

Natural amenorrhea
During the normal course of your life, you may experience amenorrhea for natural reasons, such as:

*Pregnancy
*Breastfeeding
*Menopause

Medications
Certain medications can cause menstrual periods to stop, including some types of:

*Antipsychotics
*Cancer chemotherapy
*Antidepressants
*Blood pressure drugs
*Allergy medications

Lifestyle factors
Sometimes lifestyle factors contribute to amenorrhea, for instance:

*Low body weight. Excessively low body weight — about 10% under normal weight — interrupts many hormonal functions in the body, potentially halting ovulation. Women who have an eating disorder, such as anorexia or bulimia, often stop having periods because of these abnormal hormonal changes.

*Excessive exercise. Women who participate in activities that require rigorous training, such as ballet, may find their menstrual cycles interrupted. Several factors combine to contribute to the loss of periods in athletes, including low body fat, stress and high energy expenditure.

*Stress. Mental stress can temporarily alter the functioning of your hypothalamus — an area of your brain that controls the hormones that regulate your menstrual cycle. Ovulation and menstruation may stop as a result. Regular menstrual periods usually resume after your stress decreases.

Hormonal imbalance
Many types of medical problems can cause hormonal imbalance, including:

*Polycystic ovary syndrome (PCOS). PCOS causes relatively high and sustained levels of hormones, rather than the fluctuating levels seen in the normal menstrual cycle.

*Thyroid malfunction. An overactive thyroid gland (hyperthyroidism) or underactive thyroid gland (hypothyroidism) can cause menstrual irregularities, including amenorrhea.

*Pituitary tumor. A noncancerous (benign) tumor in your pituitary gland can interfere with the hormonal regulation of menstruation.

*Premature menopause. Menopause usually begins around age 50. But, for some women, the ovarian supply of eggs diminishes before age 40 and menstruation stops.

Structural problems
Problems with the sexual organs themselves also can cause amenorrhea. Examples include:

*Uterine scarring. Asherman’s syndrome, a condition in which scar tissue builds up in the lining of the uterus, can sometimes occur after a dilation and curettage (D&C), cesarean section or treatment for uterine fibroids. Uterine scarring prevents the normal buildup and shedding of the uterine lining.

*Lack of reproductive organs. Sometimes problems arise during fetal development that lead to missing parts of the reproductive system, such as the uterus, cervix or vagina. Because the reproductive system didn’t develop fully, menstrual cycles aren’t possible later in life.
Structural abnormality of the vagina. An obstruction of the vagina may prevent visible menstrual bleeding. A membrane or wall may be present in the vagina that blocks the outflow of blood from the uterus and cervix.

Question 46

Describe the adrenal androgens and androgenic syndrome

Answer 46

*Mainly male hormones active
*low production of female sex hormones( progesterone and estrogen)
*Plays a role in secondary sexual characteristics in females
*

Question 47

Where are androgens produced?

Answer 47

Zona reticularis of the adrenal cortex

Question 48

Effects of the androgenic syndrome in females

Answer 48

*deep voice
*baldness
*Masculine distribution of hair in the body
*Growth of clitoris to resemble male organ
*Deposition of protein characteristic of males

Question 49

If fertilization occurs the corpus luteum will act as a temporary endocrine structure to release hormones. It will do this until the placenta is fully developed to take over with hormone secretion and this occurs at approximately?*

Answer 49

This occurs at 8 weeks gestation. The corpus luteum will disintegrate and turn into the corpus albicans.

Question 50

When is the fertile period?

Answer 50

Ovulation occurs on cycle day 14 and the egg lives for 24 hours. Sperm can live inside the woman’s reproductive track for approximately 5 days. Therefore, 5 days before ovulation a woman is fertile and 24 hours after ovulation (days can vary for ovulation depending on a woman’s cycle. .therefore the patient should avoid having sexual intercourse on cycle days 9-16).

Question 51

What term is used to refer to heavy menstrual bleeding?

Answer 51

menorrhagia

Question 52

Outline possible causes of heavy menstrual bleeding

Answer 52

*Hormone imbalance. In a normal menstrual cycle, a balance between the hormones estrogen and progesterone regulates the buildup of the lining of the uterus (endometrium), which is shed during menstruation. If a hormone imbalance occurs, the endometrium develops in excess and eventually sheds by way of heavy menstrual bleeding.

A number of conditions can cause hormone imbalances, including polycystic ovary syndrome (PCOS), obesity, insulin resistance and thyroid problems.

*Dysfunction of the ovaries. If your ovaries don’t release an egg (ovulate) during a menstrual cycle (anovulation), your body doesn’t produce the hormone progesterone, as it would during a normal menstrual cycle. This leads to hormone imbalance and may result in menorrhagia.

*Uterine fibroids. These noncancerous (benign) tumors of the uterus appear during your childbearing years. Uterine fibroids may cause heavier than normal or prolonged menstrual bleeding.

*Polyps. Small, benign growths on the lining of the uterus (uterine polyps) may cause heavy or prolonged menstrual bleeding.

*Adenomyosis. This condition occurs when glands from the endometrium become embedded in the uterine muscle, often causing heavy bleeding and painful periods.

*Intrauterine device (IUD). Menorrhagia is a well-known side effect of using a nonhormonal intrauterine device for birth control. Your doctor will help you plan for alternative management options.

*Pregnancy complications. A single, heavy, late period may be due to a miscarriage. Another cause of heavy bleeding during pregnancy includes an unusual location of the placenta, such as a low-lying placenta or placenta previa.

*Cancer. Uterine cancer and cervical cancer can cause excessive menstrual bleeding, especially if you are postmenopausal or have had an abnormal Pap test in the past.

*Inherited bleeding disorders. Some bleeding disorders — such as von Willebrand’s disease, a condition in which an important blood-clotting factor is deficient or impaired — can cause abnormal menstrual bleeding.

*Medications. Certain medications, including anti-inflammatory medications, hormonal medications such as estrogen and progestins, and anticoagulants such as warfarin (Coumadin, Jantoven) or enoxaparin (Lovenox), can contribute to heavy or prolonged menstrual bleeding.

*Other medical conditions. A number of other medical conditions, including liver or kidney disease, may be associated with menorrhagia

*Abortion

Question 53

What is the purpose of the uterine cycle?

Answer 53

To prepare for the arrival of a fertilized ovum that will develop until birth

Question 54

Age for menopause?

Answer 54

45-55

Question 55

Outline the flow of how number of oocytes decline from foetal development to 1 egg being released

Answer 55

Fetal development: 6 million oocytes
At birth: 1-2 million
At puberty: 300 0000- 400 000
At maturation: 1000
Ovulation: only one normally but they can be more than one egg resulting in multiple