Sexual reproduction in human beings

Sexual reproduction

• It is a reproduction which involves male and female sex cells.

Male reproductive system

• The male sex cells are called sperms.
• Parts: Penis - transfer sperms to the vagina
                     - allows urine to leave the body
            Testis - produces sperms and male sec hormones
            Urethra - transport sperms, semen and urine to outside of the penis
            Scrotum - holds the testis outside the body
            Vas deferens - transport sperms to the penis
            Seminal vesicles - produces fluids that mix with sperms to form semen
            Epididymis - stores sperms

Female reproductive system

• The female sex cells are called eggs (or ova).
•           Ovary - produces eggs and female sex hormones
•           Vagina - allows sperms to deposit
• Parts: Uterus - allows the implantation of embryo to occur and nourishes the growth of the foetus
            Fallopian tube - transport eggs from the ovaries to the uterus
                                   - allows fertilization to take place
            Vagina - allows sperms to deposit
            Ovary - produces eggs and female sec hormones

Fertilization

• Fertilization is the fusion of the nucleus of a sperm and the nucleus of an egg to form a fertilized egg called zygote.
• The fertilized egg contains 23 pairs of chromosomes.
• As the zygote contains both parents' chromosomes, the child will inherit certain characteristics from both parents. It is called heredity.
• The zygote develops into a ball of cells called embryo. The embryo implants into the uterus wall. The process is known as implantation.
• The function of the placenta: - provides food, oxygen and water from the mother's blood to the baby's
                                                blood
                                              - removes waster products such as carbon dioxide from the baby's
                                                 blood

Menstruation

• Ovulation and menstruation are parts of the menstrual cycle.
• A menstrual cycle has an average of 28 days.