Human Sexual Reproduction 12.1 & 12.2

See diagrams in your book, Human Biology and Health Studies pages 86-89

Aim:

 

To identify and explain the structure and function of the human male and female sex organs.

 

Objectives:

 

Identify on the diagrams provided and explain the significance to reproduction of the following human bio-structures: 

                                                                     Ovary

                                                       Oviduct (Fallopian Tube)

                                                       Uterus

                                                       Cervix

                                                       Vagina

                                                       Penis

                                                       Testis

                                                       Scrotal Sac

                                                       Sperm Duct (Vas Deferens)

                                                       Prostrate Gland

                                                       Urethra

 

To name the two main hormones that control human sexual cycles. Oestrogen, Progesterone

 

Describe how these hormones change with, and in turn effect the female menstrual cycle.

 

 

 

 

 

 

 

 

 

Female Reproductive Cycle

 

All the eggs a woman ever has are present in her Ovaries at birth.

 

Once a female reaches puberty she begins to Ovulate or release Ova form the Ovaries in her reproductive system.

 

From this time on an Ova is released from the Ovaries once every four weeks or so, the Ova is usually released alternately from one Ovary and then the other.

 

Ova are produced through a unique form of cellular division called Meiosis.

 

Meiosis results in the formation of gametes.

 

Gametes contain half the number (Haploid) of chromosomes than do other cells (Diploid) of an organism.

 

Haploid N = 23 chromosomes in human.

Diploid N = 46 chromosomes in human.

 

Ovulation: the release of an ova happens roughly halfway between a woman’s periods.

 

After release, beating cilia move the egg along the fallopian tube along with contractions of the oviducts muscles.

 

Menstrual Cycle: the regular patterns of change that occur in a woman’s reproductive system between one period to another.

 

 

 

 

 

 

Menstrual Cycle

 

Series of changes that take place in the body of a woman to prepare for the possibility of pregnancy.

 

Lasts 25-32 days.

 

Changes occur in  lining of the uterus, development and release of the egg, and levels of the two main ovarian hormones, progesterone and oestrogen.

 

Oestrogen causes an Ova to mature in the Ovary.

 

Oestrogen and progesterone promote the increase in blood vessels of the uterus thickening the organs walls.

 

If progesterone levels get high enough they stop further ovulation.

 

If an ova is fertilized then its corpus luteum goes on producing progesterone in the ovary and this prevents further ovulation.

 

If no fetilzation occurs then the progesterone levels decline and the thickened uterine wall is shed into the menstrual flow which is followed by the start of another cycle.

 

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