Reproduction PDF

# Reproduction The uses of the reproductive system. ## Reproduction Reproduction allows for the continuation of a species. It is a biological process by which off springs of a species are produced. There are two types of reproduction: - Asexual - Sexual ### Asexual Reproduction Involves only one...

# Reproduction The uses of the reproductive system. ## Reproduction Reproduction allows for the continuation of a species. It is a biological process by which off springs of a species are produced. There are two types of reproduction: - Asexual - Sexual ### Asexual Reproduction Involves only one parent where the offspring is genetically identical to the one parent. This type of reproduction is common among plants. Examples of sexual reproduction are: - budding - Fission ### Sexual Reproduction This type of Reproduction involves two parents; 1 male and 1 female. It occurs where a sperm and an egg fuse together during fertilization. This type of reproduction is common among animals. ## Reproduction in humans Sexual reproduction in human beings can only place when a child has reached puberty. Puberty is the stage of growth in a human being when his or her reproductive organs start to produce sex hormones and mature reproductive cells (jamete). ### Puberty Puberty is a period of rapid growth with many physical and emotional changes in the body. ### Changes during Puberty | Boy | Girl | |-----------------------|-----------------------| | Testes produce sperm & sex hormones | Ouaries release mature eggs & produce sex hormones | | Height increases rapidly | Height increases rapidly | | Shoulders widen, body becomes more muscular | Hips become wider | | Facial hair grows, hair grows on chest, armpists & pubic region | Hair grows in the armpits & pubic region | - Asexual Potato bandanya - Sexual human sheep. ## Functions of the parts of the male reproductive system | Parts of the System | Function | |-------------------------------------------|-------------------------------------------------------------------------------------------------| | Bladder | Stores urine | | Seminal Vesicle | Produces and stores fluid that eventually becomes semen. | | Vas deferens (sperm duct) | Transfers sperm from the testes to the urethra in penis. | | Penis | Carries urine from the bladder outside of the body. Releases semen that contains sperm. | | Urethra | Serves as a pathway for the exit of urine and also sperm | | Scrotal Sac | Holds the testis at a temperature slightly lower than body temperature | | Testis (singular) | Produces semen (male gonads) in large numbers from puberty throughout the rest of life. | | | Secretes testosterone that stimulates sperm production and development of secondary sexual characteristics. | ## Female Reproductive System The ovaries are the females gonads. They are the organs that make and release the female gametes (ovum legs). The ovaries also secrete the hormones progesterone and oestrogen. - Ovary - Oviduct - Uterus - Cervix - Vagina ## Male Reproductive System The male reproductive system is less complex than the female reproductive system. The male reproductive system is specialized for the following functions: - To produce and transport sperm and its protective fluid (semen). - To discharge sperm within the female reproductive tract. - To produce sex hormones. The male reproductive organs/gonads are the testes. They produce the male gamete spermatozoa (sperm) and secrete the male hormones testosterone. ## Functions of the parts in the female reproductive system | Parts of System | Function | |------------------|-----------------------------------------------------------------------------------------------------------------------------| | Uterus | Nurture the fertilized egg. Site for implantation. Early development of embryo. | | Cervix | Secrets mucus during menstrual cycle. Allows for flow of menstrual blood from the uterus. Directs the sperm into the uterus.| | Fallopian tube | Tube that moves the egg from ovary to uterus using cilia. Site of fertilization | | Ovary | Produces and releases ovum/egg. Secretes progesterone | | Fimbriae | Small finger-like projections at the end of fallopian tubes, through which the eggs move more easily from ovaries. | | Vagina | Widens during childbirth to make way for the baby | ## Say whether each of the following is true or false. 1. Both semen and urine can exit through the urethra at the same time **T** 2. The prostate gland provides the nutritious fluid for the sperm. **F** 3. The testes must always be kept warmer than body temperature. **T** 4. Oestrogen is the main male hormone. **F** 5. The foetus develops in the uterus. **F** 6. Female sex cells are produced in the ovaries. **T** 7. Sperm are made in the uterus. **F** ## Male & Female Reproductive System: Gametes The ovum and sperm cells are gametes. They are specialized reproductive cells. Each gamete contains half the genetic information to produce a full human. - **Sperm** are produced in the testis. It has a head with a large nucleus and a small amount of cytoplasm, a tail (flagellum) that enables it to move about by lashing its tail. - **Ovum** or ovum has a ball-like structure surrounded by a layer of jelly. It consists of a nucleus and a large amount of cytoplasm that contains energy for the sperm. It cannot move by itself, unlike males. It is a female egg born with a certain number of potential eggs. She will not produce any more during her lifetime. **Ovum** - One released from ovaries. Thousands produced continuously per month from puberty onwards to menopause. - Larger than Sperm - Lives for about 24 hours after ovulation - Can only be moved by cilia in oviduct. **Sperm** - Smaller than Ovum - Lives for about two-three days in the female body. - Swims actively using tail. ## Ovulation After a female reaches about once a month an ovum (egg) is released from one of her ovaries. This is called ovulation. The egg cell travels along a narrow tube called the oviduct or fallopian tube towards the womb (uterus). ## Fertilization Male and female sex cells are adapted to bring about fertilization. They are called gametes. They are deposited in the vagina. A few hundred arrive at the fallopian tube. If sperm is found in the oviduct a mature egg will wander about. After a while one of them will make contact with the egg’s cell membrane and enter into the cell. The egg will close up its cell membrane to stop any more sperm entering. The unsuccesful sperm will soon die off. The egg cell is now called a zygote. ## Pregnancy The female’s first sign she is pregnant is when her monthly periods stop. When her body decides to develop a baby in the uterus it releases hormones to prevent further ovulation. The zygote will travel slowly along the fallopian tube towards the uterus, where it will lodge. The zygote will divide again and again from a single cell. The embryo. Upon reaching the uterus the embryo implants itself into the thicker blood lining of the uterus. After about eleven weeks the embryo will develop into a fetus that has all the major organs. The fetus obtains nutrients from the mother’s blood through the placenta. Waste products from the fetus are passed into the mother’s blood to be removed. A flexible cord called the umbilical cord carries blood between the placenta and the fetus. ## Gestation Period The fetus will continue to develop into a baby and about nine months into fertilization the baby is ready. This period of time is called the gestational period. ## Menstruation Each month the lining of the uterus prepares itself for