1)The menstrual cycle refers to the changes and the preparation that a women body goes through to prepare for pregnancy.
2)About once a month, the uterus grows a new lining (endometrium) to get ready for fertilized egg.
3)When there is no fertilized egg to start the pregnancy, the uterus sheds its lining starting off the monthly menstrual bleeding also called menstrual period.
4)The average cycle is 28 days, although it is perfectly normal to have a cycle in that is as short as 21 days or long as 35 days.
5)A regular menstrual cycle is an important element of successful concepton.
#The four main phases of menstrual cycle are :
1- menstruation
2- the follicular phase
3-ovulation
4-the luteal phase.
1)The menstrual cycle refers to the changes and the preparation that a women body goes through to prepare for pregnancy.
2)About once a month, the uterus grows a new lining (endometrium) to get ready for fertilized egg.
3)When there is no fertilized egg to start the pregnancy, the uterus sheds its lining starting off the monthly menstrual bleeding also called menstrual period.
4)The average cycle is 28 days, although it is perfectly normal to have a cycle in that is as short as 21 days or long as 35 days.
5)A regular menstrual cycle is an important element of successful concepton.
#The four main phases of menstrual cycle are :
1- menstruation
2- the follicular phase
3-ovulation
4-the luteal phase.
DEFINITION OR MEANING OF MENSTRUAL (REPRODUCTIVE) CYCLE:-
Menstruation (Greek word, men-month) is monthly uterine bleeding out flowing through vagina into vulva for 4-5 days every 28 days (24-35 days)during reproductive life of a woman from menarche to menopause.
The Menstrual cycle of 28 days starts on day of onset of menstruation and ends at day 28 on start of next mens.
The cycle consists of a series of changes taking place concurrently in the ovaries and uterine lining, stimulated by changes in blood concentration of hormones.
Follicular development and selection- introduction , synopsis , follicular development stages , Follicular development and hormone , follicular development explanation through the different diagram , follicular development fertilization , reference etc.
Can be use for teachers to teach for IGCSE and SPM syllabus.
Describe the menstrual cycle in terms of changes in the ovaries and in the lining of the uterus
Describe the sites of production of oestrogen and progesterone in the menstrual cycle and in pregnancy
Explain the role of hormones in controlling the menstrual cycle and pregnancy
Ovarian cycle (the guyton and hall physiology)Maryam Fida
Ovarian cycle
The germ cells that migrate into the ovaries during early embryonic development multiply, so that by about 5 months of gestation (prenatal life) the ovaries contain approximately 6 million to 7 million oogonia.
Most of these oogonia die prenatally through a process of apoptosis.
The production of new oogonia stops at this point and never resumes again.
The oogonia begin meiosis toward the end of gestation, at which time they are called primary oocytes.
Like spermatogenesis in the prenatal male, oogenesis is arrested at prophase I of the first meiotic division.
The primary oocytes are thus still diploidPrimary oocytes decrease in number throughout a woman’s life.
The ovaries of a newborn girl contain about 2 million Primary oocytes—all she will ever have.
Each Primary oocyte is contained within its own hollow ball of single layer of granulosa cells, the Primordial follicle.
By the time a girl reaches puberty, the number of Primary oocytes and follicles has been reduced to 400,000.
Only about 400 of these Primary oocytes will ovulate during the woman’s reproductive years, and the rest will die by apoptosis.
Oogenesis ceases entirely at menopause
Definition:
“Monthly rhythmical changes in the secretion of the female hormones and corresponding physical changes in the ovaries and other sexual organs”.
Duration: The duration of the cycle averages 28 days. It may be as short as 20 days ar as long as 45 days.
PHASES
Follicular Phase (Proliferative Phase) (1-14 Day)
Menstrual Phase (Day 1-5)
Preovulatory Phase. (Day 6-14)
Ovulation (Day 14)
Post Ovulatory Phase (Secretory Phase). (15-28 Day)
Leuteal Phase (Day 15-26)
Premenstrual phase. (Last 2 Day)
Concept of Hypothalamic-Pituitary-ovarian Axis
Overall, the most advanced follicle reduces the FSH supply to other follicles while at the same time it makes itself more sensitive to the FSH that remains.
The less developed, less sensitive follicles undergo atresia, while the most developed follicle attains a diameter of up to 2.5 cm. This follicle, called a mature (graafian) follicle, protrudes from the surface of the ovary like a blister.
As the follicle matures, the primary oocyte completes meiosis I and becomes a secondary oocyte.
This cell begins meiosis II but stops at metaphase II. It is now ready for ovulation.
FSH and estrogen also stimulate the maturing follicle to produce LH receptors, which are important to the next phase of the cycle
DEFINITION OR MEANING OF MENSTRUAL (REPRODUCTIVE) CYCLE:-
Menstruation (Greek word, men-month) is monthly uterine bleeding out flowing through vagina into vulva for 4-5 days every 28 days (24-35 days)during reproductive life of a woman from menarche to menopause.
The Menstrual cycle of 28 days starts on day of onset of menstruation and ends at day 28 on start of next mens.
The cycle consists of a series of changes taking place concurrently in the ovaries and uterine lining, stimulated by changes in blood concentration of hormones.
Follicular development and selection- introduction , synopsis , follicular development stages , Follicular development and hormone , follicular development explanation through the different diagram , follicular development fertilization , reference etc.
Can be use for teachers to teach for IGCSE and SPM syllabus.
Describe the menstrual cycle in terms of changes in the ovaries and in the lining of the uterus
Describe the sites of production of oestrogen and progesterone in the menstrual cycle and in pregnancy
Explain the role of hormones in controlling the menstrual cycle and pregnancy
Ovarian cycle (the guyton and hall physiology)Maryam Fida
Ovarian cycle
The germ cells that migrate into the ovaries during early embryonic development multiply, so that by about 5 months of gestation (prenatal life) the ovaries contain approximately 6 million to 7 million oogonia.
Most of these oogonia die prenatally through a process of apoptosis.
The production of new oogonia stops at this point and never resumes again.
The oogonia begin meiosis toward the end of gestation, at which time they are called primary oocytes.
Like spermatogenesis in the prenatal male, oogenesis is arrested at prophase I of the first meiotic division.
The primary oocytes are thus still diploidPrimary oocytes decrease in number throughout a woman’s life.
The ovaries of a newborn girl contain about 2 million Primary oocytes—all she will ever have.
Each Primary oocyte is contained within its own hollow ball of single layer of granulosa cells, the Primordial follicle.
By the time a girl reaches puberty, the number of Primary oocytes and follicles has been reduced to 400,000.
Only about 400 of these Primary oocytes will ovulate during the woman’s reproductive years, and the rest will die by apoptosis.
Oogenesis ceases entirely at menopause
Definition:
“Monthly rhythmical changes in the secretion of the female hormones and corresponding physical changes in the ovaries and other sexual organs”.
Duration: The duration of the cycle averages 28 days. It may be as short as 20 days ar as long as 45 days.
PHASES
Follicular Phase (Proliferative Phase) (1-14 Day)
Menstrual Phase (Day 1-5)
Preovulatory Phase. (Day 6-14)
Ovulation (Day 14)
Post Ovulatory Phase (Secretory Phase). (15-28 Day)
Leuteal Phase (Day 15-26)
Premenstrual phase. (Last 2 Day)
Concept of Hypothalamic-Pituitary-ovarian Axis
Overall, the most advanced follicle reduces the FSH supply to other follicles while at the same time it makes itself more sensitive to the FSH that remains.
The less developed, less sensitive follicles undergo atresia, while the most developed follicle attains a diameter of up to 2.5 cm. This follicle, called a mature (graafian) follicle, protrudes from the surface of the ovary like a blister.
As the follicle matures, the primary oocyte completes meiosis I and becomes a secondary oocyte.
This cell begins meiosis II but stops at metaphase II. It is now ready for ovulation.
FSH and estrogen also stimulate the maturing follicle to produce LH receptors, which are important to the next phase of the cycle
2. Physiology of menstruationthe ovaries... 1. Hypothalamus releases GnRH (LHRH) 2. Release of GnRH triggers APG to release FSH and LH FSH- responsible for the maturation of ovum and follicle formation. Causes an increase in estrogen LH – triggers ovulation and growth of uterine lining
3. 2.1 FSH activates primordial follicles to mature. 2.2 Primordial follicles start producing follicular fluid that is HIGH IN ESTROGEN (estradiol) and some progesterone 2.3 primordial follicles propelled toward the surface of ovary and is now called Graafian Follicle. 3. Graafian follicle undergoes cell division (mitosis, meiosis) 3.1 GF divides into: 3.1.a primary oocyte – with more cytoplasm 3.1.b secondary oocyte – with less cytoplasm 3.2 GF after meiosis contain haploid cells (23 chromosomes)
4. 4. Upsurge in LH causes the release of prostaglandin 5. Prostaglandin causes the rupture of GF releasing ovum and follicular fluid from the follicle, leaving the follicle with a hollowed pit. 6. Increase in LH causes production of Lutein (bright yellow fluid, HIGH IN PROGESTERONE) that will fill the empty pit 7. Follicle becomes “CORPUS LUTEUM”
5. 7.1 if fertilization occurs, ovum implants at the uterus, corpus luteum stays inside the ovaries until 16-20 weeks; trophoblast begin secreting HCG 7.2 without fertilization, ovum atrophies after 4-5 days, CL remains for only 8-10 days. 7.2.a CL replaced by white fibrous tissue, CL becomes “CORPUS ALBICANS”