Female reproductive cycle

Female reproductive cycle

Is a periodic uterine bleeding in response to cyclic hormonal changes.It allow for conception and implantation of a new life.

Female reproductive cycle( Menstruation )

To bring an ovum to maturity and renew the uterine tissue bed that will be responsive to its growth once its fertilized.Menarche ( first menstruation)May occur as early as age 9 or as late as age 17 purpose

Varies from women to womenInterval between cycles : average 28 days, cycles of 23 to 35 days .Average length of the menses is 2 to 7 days, put ranges of 1-9 days not abnormal.Amount of menstrual flow: difficult to estimate, average 30 to 80 ml per menstrual period, saturating a pad in less than hour is heavy bleeding .Color of menstrual flow: Dark red, a combination of blood, mucus, and endometrial cells

Initiated by the release of luteinizing hormone- releasing hormoneThe menstrual cycle

1- hypothalamus2- pituitary gland3- ovaries4- uterus4 body structures are involved in the physiology of the menstrual cycle.

Luteinizing hormone releasing hormone( LHRH), also known as gonadotropin releasing hormone ( GnRH), from the hypothalamus.1-The release of LHRH hormone from hypothalamus initiates the menstrual cycle, the presence of estrogen repress the hormone .The menstrual cycle

2-Under the influence of LHRH, the anterior lobe of the pituitary produces two hormones that act on the ovaries to further influence the menstrual cycle.1 -follicle-stimulating hormone ( FSH)( active early in the cycle and is responsible for maturation of the ovum.2 -Luteinizing hormone ( LH) most active at the midpoint of the cycle and is responsible for ovulation or release of the mature egg cell from ovary and growth of the uterine lining.

Cont -The menstrual cycle

Phases of the menstrual cycle

Phases of the menstrual cycle

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Follicular PhaseLuteal PhaseProgesteroneEstrogenFSHLH

1- Menstrual phase ( days 1 through 5 )Estrogen and progesterone levels decreaseFSH levels rise, and steady levels of LH influence the ovary to secrete estrogen Menstrual flow beginsPhases of the menstrual cycle

2- Proliferative( follicular) phase (days 6 through 13)Estrogen production increases, leading to proliferation of endometrium and myometrium in preparation for possible implantation of a fertilized ovumFollicle stimulates graafian follicleFSH production decrease before ovulation ( around day 14) Phases of the menstruation

3-Secretory (luteal ) phase ( days 14 through 25)The corpus luteum forms under the influence of LH Estrogen and progesterone production increaseThe endometrium is prepared for implantation of fertilized ovum Phases of the menstruation

4- Ischemic phase ( days 26 through 28)The corpus luteum degenerates if conception doesnt occurEstrogen and progesterone levels decline if conception doesnt occurPhases of the menstruation

Ovum from ovulation to fertilizationZygote from fertilization to implantation.Embryo from implantation to 5-8 weeks.Fetus from 5-8 weeks until term.Conception developing embryo or fetus and placental structures throughout pregnancy.Stages of fetal development

Occurs with the fusion of a spermatozoon and an ovum ( oocyte) in the ampulla of the fallopian tube.The fertilized egg is called a zygote.The diploid number of chromosomes (44 autosomes and 2 sex chromosomes ) is restore when the zygote is formed . fertilization

A male zygot is formed if the ovum is fertilized by a spermatozoon carrying a Y chromosome.A female zygote is formed if the ovum is fertilized by a spermatozoon carrying an X chromosomefertilization

Cellular multiplication occurs when the zygote undergoes mitosis, dividing into two cells, four cells and so on These cells, called blastmeres, eventually form the morula, a solid ball of cells.fertilization

After the morula enters the uterus, a cavity forms within the dividing cells, thus changing the morula into a blastocyst.The blastocyst cells differentiate into one of two forms trophoblast, which develop into fetal membranes and contribute to, placenta formation, or the inner cell mass, which will form the embryo. fertilization

fertilization

Implantation or contact between the growing structure and the uterine endometriumOccurs approximately 8 to 10 days after fertilization Implantation

Implantation

The deciduaRefers to the endometrial lining during pregnancy Provides a nesting place for the developing ovum

Has some endocrine functions - secretes prolactine to promote lactation - secretes relaxin, which relax the connective tissue of the symphysis pubis and pelvic ligaments, also promotes cervical dilation. - secretes prostaglandin, a potent hormone like fatty acid, important for mediating several physiologic functions

Embryonic and fetal structure

Chorionic VilliFinger like structures that protruded from the blastocyst.In placentation, the chorionic Villi invade the decidua.This becomes the fetal portion of the future placenta.

Embryonic and fetal structure

A flat disk shaped structure formed from the chorion, chorionic Villi, and adjacent decidua basalis.Contains 15 to 20 subdivisions called cotyledons.Wight 450 to 600 g, measures from 15 to 25.5 cm in diameter, and is 2.5 to 3 cm thick at full term.Has a rough texture, appears red on the maternal surface and shiny and gray on the fetal surface .placenta

placenta

Functions as a transport mechanism between the mother and the fetus, from the 3rd month of pregnancy until birth.It produces hormones, including human chorionic gonadotropin, gonadotropin releasing hormone, estrogen, and progesterone.Function of the placenta

It supplies the fetus with carbohydrates, water, fats, protein, minerals, and inorganic salts.It carries end products of fetal metabolism to the maternal circulation for excretion.It transfers passive immunity via maternal antibodies. Function of the placenta

Fetal circulation

Umbilical vein carries oxygenated blood to the fetus from the placenta.Umbilical arteries carry deoxygenated blood from the fetus to the placenta .Foramen ovale serves as the septal opening between the atria of the fetal heart .

Fetal circulation

Ductus arteriosus connects the pulmonary artery to the aorta, allowing blood to shunt around the fetal lungs.Ductus venosus carries oxygenated blood from the umbilical vein to the inferior vena cava, bypassing the liver.Fetal circulation

Serves as the lifeline from the embryo to the placenta.Measures 50 cm in length and 2 cm in diameter at full term.Contains two arteries and one veinThe umbilical arteries transport blood from the fetus to the placentaThe umbilical vein returns blood to the fetus from the placenta.Umbilical cord

Contains whartons jelly, a gelatinous substance that helps prevent kinking of the cord in utero.Blood flow through the cord at a bout 400 ml\min. Umbilical cord

Umbilical cord

Chorionic membrane is closest to the uterine wallAmnion is the inner fetal membrane and lines the amniotic sac.The amniotic membranes

Is enclosed within the chorionGradually increase in size and surrounds the embryo.Fuses with the chorion by the 8th week of gestation.Contains fluid, known as amniotic fluid.

Amniotic sac

Helps provide the fetus with a buoyant, temperature controlled environment.Serves as a fluid wedge that helps to open the cervix during birth .Amniotic fluid

Early in pregnancy comes from three sources: - fluid is filtered into the amniotic sac from maternal blood as it passes through the uterus ( most) . - fluid is filtered into the sac from fetal blood passing through the placenta. - fluid diffuses into the sac from the fetal skin and respiratory tract.Amniotic fluid

Later in pregnancy, when the fetal kidneys begin to function, the fetus urinates into the amniotic fluid fetal urine then becomes the major source of amniotic fluid.Amniotic fluid

Replaced every 3 hours - production of amniotic fluid from maternal and fetal sources balances amniotic fluid lost through the fetal GI tract. - normally, the fetus swallows up to several hundred milliliters of amniotic fluid per day. This fluid is absorbed into the fetal circulation from the fetal GI tract. - some is transferred from the fetal circulation to the maternal circulation and excreted in maternal urine.

Amniotic fluid

Contains: albumin, lanugo, urea, creatinine, bilirubin, fat, fructose, protein, enzymes, lecithin, sphingomyelin, and leukocytesPrevents heat loss.Cushion the fetus.Facilitates symmetrical fetal growth and development.Provide a source of oral fluid.Serves as a respiratory for fetal wasteComponent and function of amniotic fluid

At term, the uterus contains 800 to 1200 ml of amniotic fluid, which is clear and yellowish and has a specific gravity of 1.007 to 1.025 and a pH of 7.0 to 7.25.The amount of amniotic fluid

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