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Human Reproduction http://www.youtube.com/watch?v=nLmg4wSHdxQ.

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Presentation on theme: "Human Reproduction http://www.youtube.com/watch?v=nLmg4wSHdxQ."— Presentation transcript:

1 Human Reproduction

2 Memory Check Answers 1. a) What is the role of sex hormones?
Sex hormones are messengers that travel through the bloodstream to tell the testes or ovaries when to produce gametes b) Name at least 2 sex hormones - Testosterone, Progesterone, Estrogen

3 2. Describe the changes to the bodies of girls and boys during puberty.
Both: Appearance of pubic hair and increase of other body hair Girls: Development of breasts, menstrual cycle Boys: Larynx causes voice to deepen, lowering of the testies

4 3. a) Describe the life span of a spermatanoon from its birth in a testicle to its death in a fallopian tube. The sperm are produced in the testicles and stored in an organ that lies above it called the epididymis. When ejaculation occurs, the sperm leave the epididymis through a tube called the vas deferens where they are mixed with semen that helps protect and feed the sperm.

5 (3. a) cont.) The sperm and semen then leave the body through the urethra in the penis to enter the female’s vagina. The sperm then travel up the vagina, enter the uterus and continue into the fallopian tube, where most will die but one may successfully fertilize an egg

6 3) b) Describe the life of an unfertilized ovum, from birth to death
Once every 28 days (approx) one ovary will release one ovum in a process called ovulation. This ovum will enter the fallopian tube and start travelling down towards the uterus. Unfertilized ova can survive between 24 and 48 hours in the fallopian tube. If it is not fertilized and dies it will reach the uterus and then be expelled with the now “not needed” thickened uterine lining

7 4) Why does the lining of the uterus thicken during the menstrual cycle?
It thickens in preparation for a fertilized ovum. If it is not needed it will be shed through the vagina. If the egg is successfully fertilized and attaches itself properly to the uterine lining then this thickened lining will serve to protect and nourish the zygote as it begins to develop

8 Human Reproduction Notes
Purpose of Sex Hormones: Send messages between the brain and the genital organs to either begin or continue development or to prepare for reproduction.

9 Male Sex Hormone: Testosterone
Produced in the testes, Key in the development of the testacles and prostate, Increase in the body results in increased muscle and bone mass as well as hair growth. The male body produces 10x more than the female

10 Testosterone FUNCTIONS: C19H28O2

11 Female Sex Hormone: Estrogens
Primary female sex hormone but men also have small amounts, Promotes the growth and development of breasts, Regulates the menstrual cycle, thickens the endometrial lining, Decelerates height growth and reduces muscle mass

12 Estrogen: C18H24O2 -maintain body temp. -delay memory loss
-regulate and prepare the body for sexual and reproductive development -regulate production of cholesterol (liver) -decreases plaque in the arteries -stimulates maturation of the ovaries -stimulate the start of the menstrual cycle once the reproductive system has matured -stimulates the maturation of the vagina -maintains a lubricated and thick vaginal lining -stimulates the development of the breasts -prepares the glands for future milk production -stimulates the maturation of the uterus -helps prepare the uterus for nourishing a developing foetus -helps to preserve bone density Estrogen: C18H24O2

13 Female Sex Hormone: Progesterone
Most important during pregnancy (development of the foetus) and to allow for pregnancy, Inhibits milk production (levels decrease after delivery), A sudden drop during pregnancy can cause false labour


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