the human reproduction

THE HUMAN REPRODUCTION

Reproductive System

·       Functions

The major function of the reproductive system is to make sure that the human species survives. The four main functions of the human reproductive system are:

1.    To produce egg and sperm cells,

2.    to transport and sustain these cells,

3.    to nurture the developing offspring,

4.    and to produce hormones.

·       Major Organs

In the human reproductive system, the major organs include the external genitalia and many internal organs including gamete producing gonads.

- The external genitalia are the penis and vulva and the gamete producing gonads are the testicles and ovaries.

- These organs produce the egg and sperm cells (gametes) and produce hormones.

- These hormones are needed in the maturing of the human reproductive system, the development of sexual characteristics.

- In the males, the major organ of the reproductive system is the penis

- In the females it is the vagina.

·         How it works

Reproduction couldn't happen without organs called the gonads. The female gonads are the ovaries, which produce eggs. The male gonads, testicles, produce sperm.

·         Reproduction Stages

1.   Fertilization:  -Occurs in upper 1/3 of Fallopian tube

-Once one sperm enters, egg membrane changes

-Fertilized egg = zygote

2.   Implantation: - Implanted into thick walls of uterus

-Chorion membranes dig into uterus to form placenta

- Embryo supported via umbilical cord

- Once pregnant, progesterone levels stay high in mom

3.     1^st Trimester:

-          Heart develops first

-          Neural tube develops

-          All body systems appear by Week 8 – Now a Fetus

4.     2^nd Trimester:

-          Mostly growth

-          Looks more like a baby

-          Some preemies survive at this stage

5.     3^rd Trimester:

-          More growth

-          Kicking, rolling, stretching

-          Eyes open – Week 32

-          Lungs mature

-          Rotates to head-down   position

6.   Birth

-          Labor

a.     Uterine contractions begin

b.    Cervix dilates to 10 cm.

-          Birth

c.     Uterus pushes baby through vaginal canal

-          Placenta delivered after

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