Question's

Question 1

A menstrual cycle (a female reproductive cycle) is episodic
uterine bleeding in response to cyclic hormonal changes. The
purpose of a menstrual cycle is to bring an ovum to maturity
and renew a uterine tissue bed that will be responsible for the
ova’s growth should it be fertilized.

Answer 1

MENSTRUATION

Question 2

Immediately after a menstrual flow (which occurs during the first 4 or 5 days of a cycle), the endometrium, or lining of the uterus. is very thin, approximately one cell layer in depth. As the Ovary begins to produce estrogen (in the follicular fluid, under the direction of the pituitary FSH), the endometrium begins to proliferate. This growth is very rapid and increases the thickness of the endometrium approximately eightfold. This increase continues for the first half of the menstrual cycle (from approximately day 5 to day This half of a menstrual cycle is termed interchangeably the proliferative, estrogenic, follicular, or postmen strual phase.

Answer 2

First Phase of Menstrual Cycle (Proliferative).

Question 3

After ovulation, the formation of progesterone in the corpus luteum (under the direction of LH) causes the glands of the uterine endometrium to become corkscrew or twisted in appearance and dilated with quantities of glycogen (an elementary sugar) and mucin (a protein). The capillaries of the endometrium increase in amount until the lining takes on the appearance of rich, spongy velvet. This second phase of the menstrual cycle is termed the progestational, luteal, premenstrual, arse- cretory phase.

Answer 3

Second Phase of Menstrual Cycle (Secretory)

Question 4

If fertilization does not occur, the corpus luteum in the ovary begins to regress after 8 to 10 days. As it regresses, the production of progesterone and estrogen decreases. With the withdrawal of progesterone stimulation, the endometrium of the uterus begins to degenerate (at approximately day 24 or day 25 of the cycle). The capillaries rupture, with minute hemorrhages, and the endometrium sloughs off.

Answer 4

Third Phase of Menstrual Cycle (Ischemic)

Question 5

Menses, or the menstrual flow, is composed of

Blood from the ruptured capillaries Mucin from the glands

Fragments of endometrial tissue

The microscopic, atrophied, and unfertilized ovum Memes is actually the end of an arbitrarily defined menstrual cycle. Because it is the only external marker of the cycle, however, the first day of menstrual flow is used to mark the beginning day of a new menstrual cycle.

Answer 5

Fourth Phase of a Menstrual Cycle (Menses)

Question 6

is produced as a second product of the syncytial cells of the placenta. Estrogen con- tributes to the woman’s mammary gland development in preparation for lactation and stimulates uterine growth to accommodate the developing fetus.

Answer 6

Estrogen (primarily estriol)

Question 7

as the “hormone of mothers.” This is because, although estrogen influences a female appearance, progesterone is necessary to maintain the endometrial lining of the uterus during pregnancy. It is present in serum as early as the fourth week of pregnancy, as a result of the continua- tion of the corpus luteum. After placental synthesis begins (at about the 12th week), the level of progesterone rises progres- sively during the remainder of the pregnancy. This hormone also appears to reduce the contractility of the uterus during pregnancy, preventing premature labor. Such reduced con- tractility is probably produced by a change in electrolytes (notably potassium and calcium), which decreases the con- traction potential of the uterus.

Answer 7

Progesterone