Reproduction is the biological process where new individuals (known as ‘offsprings’) are made from older ones (known as parents). In sexual reproduction genetic material from both parents are combined, so that the offspring is different to either parent. You may have heard some children looking like the mother but having brown hair like his father. This is because he has features of both parents since his/her genetic material is a combination of the two. Thus the offspring will never be identical to just one parent.
The human body is adapted to ensure that sexual reproduction leads to the generation of new offspring. The male and female play different roles in this process. The male body is adapted to produce semen (contains sperms) and deposit this inside the female. The female body provides a suitable environment for the male genetic material to fuse with the female genetic material. Furthermore, the female body is adapted to carry the developing foetus until it is ready to be born. There are a number of processes that must take place in order for a new offspring to be created. It is important to know basic facts of human sexual anatomy and reproduction.
Puberty:
Puberty is the process of physical changes by which a child's body becomes an adult body capable of reproduction. It is the period of rapid growth and development during which a person becomes sexually mature and become capable of reproducing. Increased secretions of certain hormones in the body bring about puberty. Puberty occurs in girls at about 10 to 12 years, and about 2 years later in boys. During puberty, reproductive organs grow and develop to produce sperms or mature eggs. Dramatic physical, emotional and social changes also occur.
The process causes secondary sexual characteristics to surface, and is triggered by:
1) Release of hormones from the brain (pituitary gland) to the gonads. The gonads are the organs responsible for the production of sperm and eggs.
In males, the gonads are the testes, and in females, the gonads are the ovaries
2) In response to the hormonal signals from the brain, the gonads begin secreting sex hormones (such as testosterone and estrogen)
3) The gonads also initiate gametes production. In the testes, sperms are being prodcued while the ovaries begin maturing
Male Reproductive System:
Testis ->Produces male gametes (sperm) and male sex hormones
Prostate gland and seminal vesicle ->Produce nutrients needed for sperms and produce an alkaline liquid, which neutralises the acidic environment vaginal tract.
Penis ->To allow urination to occur in man, and allows the transfer of the sperms (semen) into the female body, through ejaculation.
Epididymis ->Stores sperm produced by testis, and also ejaculates sperms out through muscle contraction
Vas Deferens(sperm duct) ->Transports mature sperms to the urethra in preparation for ejaculation.
Urethra ->Carries the semen to the outside of the body through the penis (ejaculation).
Transfers urine from the bladder to outside of the body
•Sperms and fluid from the sex glands make up semen.
•Semen is deposited in the female passage during sexual intercourse.
•The urethra joins the base of the bladder where urine is stored.
•When a person urinates, the urine passes through the urethra to the outside.
•During sexual intercourse, the opening between the urethra and the bladder is closed so that urine and semen never mix.
Female Reproductive System:
Ovary ->Production of female gametes (ova) and release of mature ovum and female sex hormones.
Oviduct ->Ovary releases mature eggs into fallopian tubes (oviduct) once a month.
A narrow muscular tube that leads from ovary to uterus / Muscular, strong contractions / Fertilization usually occur here
Uterus ->Muscular and elastic, to push foetus out during birth / Soft and smooth endometrium prepares for implantation of fertilised egg
Cervix ->Circular ring of muscles at the lower end of the uterus / Enlarges to allow the foetus to pass through during birth
Vagina ->Birth Canal / semen is ejaculated into the vagina during copulation
•Each ovary produces about 250 mature eggs in the life of the female.
•From puberty onwards, an egg is released from one of the ovaries every month.
•When a woman is about 45 to 55 years old, the egg production slows down and finally stops.
•The woman is said to have reached the stage of menopause.
For more information, refer to my Science wikispace that I did about Sexual Reproduction. It contains mindmaps, images, comics, worksheets all on the topic itself.
http://04600465.wikispaces.com/
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