Reproductive system day3
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The document discusses human reproduction and the menstrual cycle. It describes the processes of spermatogenesis and oogenesis, in which haploid gametes are produced through meiosis. Spermatogenesis results in four sperm cells from each meiosis event in males, while oogenesis results in a single ovum and three polar bodies from each meiosis event in females. The document then explains the menstrual cycle, which occurs monthly in females and involves the thickening of the uterine lining in preparation for pregnancy, ovulation of a single ovum, and shedding of the uterine lining if fertilization does not occur.
Reproductive system day3
- 1. Reproductive System Day 3: Spermatogenesis, oogenesis and the menstrual cycle
- 2. Gametes reproductive cells (sperm and egg) haploid (single set of unpaired chromosomes) In humans we have 23 pairs or 46 chromosomes are packaged DNA formed by gametogenesis spermatogenesis oogenesis
- 3. Mitosis cell division undergoes several phases: interphase* prophase prometaphase* metaphase anaphase telophase cytokinesis* results into two identical daughter cells IF a diploid cell undergoes mitosis, the result is a diploid cell.
- 5. Meiosis Cell division results into two daughter cells with half the number of chromosomes IF a diploid cell undergoes meiosis, the resulting cells are haploid cells Meiosis only happens in gametes.
- 9. Oogenesis
- 11. Differences in gametes sperms male Meiosis results in four sperms. Sperms are motile. relatively small in the millions ova Female Meiosis results in one mature ovum and three polar bodies The ovum is nonmotile. relatively large Just one ovum is released every month.
- 12. The Sperm Cell
- 13. Parts of a sperm head: acrosome has enzymes to penetrate the egg cell triggers acrosome reaction prevents other sperms from fusing with the egg midpiece: ATP production (energy) fructose from seminal fluid tail: flagella for movement
- 14. The Ovum
- 15. Parts of an ovum yolk cytoplasm and nutritive germinal vesicle nucleus zona striata or zona pellucida protection in between the cytoplasm and corona radiata corona radiata outer protection, 2 or 3 cell layers thick
- 17. Menstrual cycle monthly cycle ~28 days In adults 21 to 35 In teens 21 to 45 “ bleeding” shedding of the endometrium of the uterus lasts 3 to 5 days
- 18. What happens in the menstrual cycle? follicle-stimulating hormone (ripening) increase of estrogen prepares the uterus for pregnancy the lining grows and thickens luteinizing hormone (release) Day 14, the ovum is released from the ovary. Progesterone prepare and maintain the endometrium Pregnancy can occur 3 days before or during ovulation.
- 19. IF fertilization does not occur: ovum breaks hormones drop the uterine lining is shed
- 20. IF fertilization occurs Egg is “planted” in the endometrium Human chorionic gonadotropian (HCG) Continues secretion of progesterone *provide the blood vessels (endometrium)
- 21. Complications of the menstrual cycle amenorrhea Lack of menstruation Excessive weight loss Stress Excessive exercising dysmenorrhea painful menstruation, cramps excess prostaglandin contracts and relaxes smooth muscles
- 22. Menopause the menstrual cycle stops happens at age 45 -55 What happens at menopause? Ovulation stops.