Human Reproduction

1. Human Reproduction Female Reproduction Systems

2. Female Sexual Characteristics • Female puberty usually begins around the age of 10 – 12 (so on average about a 1 – 2 before males begin puberty). • During puberty a female will undergo primary and secondary sexual characteristic changes. • Primary sexual characteristics is when the primary organs start to mature. • Secondary sexual characteristics include: growth of underarm hair, pubic hair, and widening of the hips for child birth.

3. Female Sexual Characteristics • Unlike a male – who does not start to produce his sperm until puberty – females have all their sex cells at birth. • A female can be born with approximately two million eggs, but will have only about 400,000 at puberty. • Once sexual maturity is reached during puberty a single egg matures and will be released each month.

4. Female Sexual Characteristics • The primary female reproductive organ is the ovary, this is where the egg cells mature and are released from. • Females have two ovaries located in the lower portion of the abdominal cavity one on either side of their sex organ. • Inside the ovaries are follicles, each follicle contains a single immature egg. The follicles contain cells that nourish and protect the developing egg. • Females are able to produce their own hormones –estrogen and progesterone – in the ovaries.

5. Menstrual Cycle/Path of the Egg • A women goes through a menstrual cycle, each cycle is typically 28 days. • The length of a women’s cycle can change the older they get. It can also change if one women lives with other females (for example in a dorm). This is known as the McClintock synchronization theory. • When a female reaches the age of 40 she goes through menopause and this is when she tends to stop producing mature eggs.

6. Menstrual Cycle/Path of the Egg • Menstruation is the shedding of the endometrium (this happens in the first stage) • There are four main stages a female goes through during a menstrual cycle • Flow Phase • Follicular Phase • Ovulation • Luteal Phase

7. Menstrual Cycle/Path of the Egg • After an egg is developed and mature it is released from the ovary into the fallopian tube – usually one egg from one ovary and the next cycle it will release an egg from the other ovary. • The fallopian tube is a tube that allows the egg to get from the ovaries to the uterus. • The lining of the uterus is called the endometrium, it is filled with rich nutrients, blood vessels and mucus that provides nourishment for the embryo.

8. Menstrual Cycle/Path of the Egg • The cervix is a muscle between the vagina and the uterus – it is clamped relatively shut and only starts to open during child birth. • The vagina has three main functions • Receives the male penis and sperm during sexual intercourse; • Is the birth canal during delivery of an offspring; and • To void the bladder

9. Menstrual Cycle/Path of the Egg

10. Menstrual Cycle/Path of the Egg • If no sperm is found in the fallopian tube to fertilize the egg, the egg will make its way to the uterus and expel through the vagina. • If fertilization does occur, it must happen within 24 hours of ovulation (when the egg is released) or the egg degenerates. • The egg moves to the uterus, and once the uterus realizes that the egg is not fertilized, it then sheds the endometrium and starts to prepare for the next cycle. • Then, once the 28th day arrives, the cycle starts all over again.

11. Pregnancy • If the egg is fertilizedin the fallopian tube, the two haploids fuse together to produce a zygote with 23 pairs of chromosomes. • After fertilization, the mass of cells created in the zygote become an embryo. • The Embryo reaches the uterus where it will implant into the endometrium. • During pregnancy the menstrual cycle stops completely while the mother-to-be awaits for the birth of her baby. • Upon the birth of an offspring, females produce a hormone called prolactin. It causes milk to be produced to feed the baby.

12. Assignment • Textbook Pg 116 – Questions 3, 4, 7, 11, 12, 14, 16