The Female Reproductive Cycle Dr Rania Abd El
The Female Reproductive Cycle Dr Rania Abd El Hamid Hussein MBBSch Master’s degree in Internal Medicine Doctor in Nutrition and Public Health Assistant Professor of Nutrition Faculty of Applied Medical Sciences KAU dr Rania Hussein
The onset of menarche starts the female reproductive cycle, which continues until menopause. dr Rania Hussein
The menstrual cycle The female reproductive years are characterized by monthly changes in the female hormones and corresponding changes in the ovaries and uterus. Each cycle lasts about 28 days. dr Rania Hussein
Follicular/ Proliferative phase • It starts with the onset of menstruation. • FSH and LH secretion ↑ → ovum enlarges → mature follicle, and cells around the ovum secrete estrogen. dr Rania Hussein
Luteal (Secretory phase) Corpus luteum is formed from cells of the follicle that remained after expulsion of the ovum. It secretes estrogen and progesterone → ↑ nutrient reserves in endometrium for fertilized ovum. dr Rania Hussein
dr Rania Hussein
The ovum is released from one ovary each month. • If fertilization → fertilized ovum (zygote) is implanted in the endometrium within the first 2 weeks. • If no fertilization → ovum is released and endometrium is discarded dr Rania Hussein
Growth and development during pregnancy dr Rania Hussein
dr Rania Hussein
Conception and implantation • Fertilization occurs in the fallopian tube to form the zygote. Several stages of division occur from zygote , to morula, to blastocyst. dr Rania Hussein
Conception and implantation • Trophoblastic cells develop over the surface of blastocyst • They are responsible for: 1. Implantation. 2. They secrete proteolytic enzymes → liquify the endometrial cells → Fluid and nutrients released from these cells are absorbed into the blastocyst. dr Rania Hussein
The Placenta • Formed as an interweaving of fetal and maternal BV embedded in the uterine wall. • It is the major source of nutrition to the fetus after 12 weeks gestation. dr Rania Hussein
The Placenta It allows: 1. diffusion of oxygen and nutrients from maternal blood to fetal blood 2. diffusion of carbon dioxide and excretory products from the fetus back to the mother. dr Rania Hussein
Umbilical cord • It extends from abdomen of the fetus to the placenta. • It is the structure through which the fetus veins and arteries reach the placenta. dr Rania Hussein
Amniotic sac The bag of water in the uterus in which the fetus flows. dr Rania Hussein
Embryonic development • Implantation (2 nd w)-8 thw • Growth results from hyperplasia • Under nutrition results in congenital anomalies • wt gain is minimal Fetal growth and development • 8 th w- labor • Hypertrophy and hyperplasia • Under nutrition results in preterm birth or fetal growth restriction • >2/3 preterm birth wt is gained dr Rania Hussein
Embryosis: Critical period • It is a period of rapid cell division → irreversible effects on later developmental stages • Why critical? 1. Those cellular activities occur only at these times → irreversible effects on later developmental stages 2. a woman is even unaware that she is pregnant. 3. Food intake may be ↓ by nausea of early pregnancy. dr Rania Hussein
• Eg: critical period for neural tube development is 17 - 30 days gestation • Malnutrition or toxins in this critical period→ NTD (neural tube defects)→ anencephaly or spina bifida dr Rania Hussein
A mother who has adequate nutrient reserves at time of conception will be at lesser risk. dr Rania Hussein
In addition • Malnutrition and starvation → ↓ fertility in men and women • If a malnourished woman gets pregnant → poor placental development → Infant physical and cognitive abnormalities dr Rania Hussein
References • Brown JE, Isaacs J, Wooldridge N, Krinke B, Murtaugh M. Nutrition through the lifecycle, 2007. 3 rd ed. Wadsworth publishing. • Mahan LK, Escott- Stamp S. krause’s food, and nutrition therapy 2008. 12 th ed. Saunders Elsevier. Canada. dr Rania Hussein
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