L5-The-menstrual-cycle.pptx

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1. Menstrual Cycle

2. Use menstrual cycle calendar to determine the nest menstruation and ovulation period. Describe the phases of menstrual cycle. Explain the occurrence of menstruation in female. LEARNING OBJECTIVES

3. List all the changes that occur in males and females during puberty. Female Male

4. Fertilization What is fertilization? Consider what the image above is showing you Why is it important? Fertilization is when a sperm cell joins with an egg cell. It is important because this is how reproduction occurs in most living things including humans

5. The menstrual cycle Why do you think menstruation takes place?

6. The menstrual cycle is the body’s way of preparing for pregnancy. It only happens in females. It is controlled by chemicals called hormones.

7. Several  hormones  are involved in the  menstrual cycle of a woman: follicle stimulating hormone (FSH)  causes the maturation of an egg in the ovary. leutenizing hormone (LH)  stimulates the release of the egg. estrogen  is involved in repairing and thickening the uterus lining Progesterone maintains the uterus lining

8. FSH is secreted by the pituitary gland. It makes eggs mature and stimulates the ovary to produce oestrogen. Uterus lining breaks down - menstruation Lining of uterus builds up Lining maintained The level of oestrogen rises. This inhibits the production of more FSH and stimulates the build up of the lining of the uterus - proliferation LH is secreted by the pituitary gland. When its level reaches a peak it stimulates the release of a mature egg from the ovary - ovulation After the egg is released the level of progesterone rise and maintains the lining of the uterus in preparation for the implantation of the fertilised egg.

9. The Menstrual Cycle 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 The main events in the cycle are: 1) Menstruation – uterus lining breaks down, blood and cells are lost. 2) Proliferation – repair of the uterus lining. 3 ) Ovulation – release of an egg from the ovary – day 14 4 hormones involved: FSH Oestrogen LH Progesterone Cycle starts again

10. Label the key events on this menstrual cycle timeline

11. Using the 28- day menstrual cycle calendar, fill-in the table with hypothetical dates of ovulation and next menstruation.

12. Menstruation (days 1-5) Changes in the uterus Changes in the ovary Follicles immature Pituitary gland releases FSH Uterus lining breaks Changes in hormone levels: