Presentation on theme: "4/29/2015 Clare Hargreaves-Norris 1 Reproductive System ACCESS H.E. Human Biology."— Presentation transcript:
4/29/2015 Clare Hargreaves-Norris 1 Reproductive System ACCESS H.E. Human Biology.
4/29/2015 Clare Hargreaves-Norris 2 Introduction Male and female reproductive systems are different in shape and structure, but both are specifically designed to produce, nourish, and transport either the ova or sperm. Male reproductive system is located both inside and outside the pelvis. Male reproductive system consists of: testes, duct system, accessory glands such as seminal vesicles and prostate, and the penis.
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4/29/2015 Clare Hargreaves-Norris 4 Testes DescriptionFunction The two testes are oval- shaped and grow to about 5 centimeters in length and 3 centimeters in diameter. They are suspended in the scrotum, outside the body. Each testicle contain approximately 200-300 lobules. Testes produce and store millions of sperm cells. Testes are also part of the endocrine system, producing hormone testosterone. Stimulates sperm production. Testosterone is responsible for the development of the secondary sexual characteristics in boys (deeper voices, bigger muscles, body/facial hair).
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4/29/2015 Clare Hargreaves-Norris 6 Duct system DescriptionFunction The duct system consists of : Seminiferous tubule. Epididymis. Vas deferens. Spermatozoa (sperm) is synthesised in the seminiferous tubule. Immature sperm develops in the epididymis, which is connected to the vas deferens. The vas deferens provides a passageway that transports the semen from the testes.
4/29/2015 Clare Hargreaves-Norris 7 Scrotum DescriptionFunction The scrotum is a pouch-like structure that hangs outside the pelvis. It houses the epididymis and the testes. The scrotum helps to regulate the temperature of the testes. The temperature needs to be kept cooler than body temperature to produce sperm. The scrotum changes size and position to maintain the correct temperature.
4/29/2015 Clare Hargreaves-Norris 8 Prostate gland DescriptionFunction Surrounds the ejaculatory ducts at the base of the urethra, just below the bladder. Produces two secretions that are part of the seminal fluid. One keeps lining of urethra moist. One helps semen to travel along the urethra and into the female.
4/29/2015 Clare Hargreaves-Norris 9 Seminal vesicle DescriptionFunction Sac like glands that are found at the base of the bladder and are connected to the prostrate gland. Also secretes seminal fluids that lubricate the duct system and nourish the sperm.
4/29/2015 Clare Hargreaves-Norris 10 Penis DescriptionFunction The penis is actually made up of two parts: the shaft and the glans. The shaft is the main part of the penis and the glans is the tip. Inside the penis is the urethra, the channel that carries the semen to the outside of the body. At the end of the glans is a small slit or opening, which is where semen and urine exit the body through the urethra. The penis, which usually hangs limp, becomes hard when a male is sexually excited. Tissues in the penis fill with blood and it becomes stiff and erect. The rigidity of the erect penis makes it easier to insert into the female's vagina during sexual intercourse. When the erect penis is stimulated, muscles around the reproductive organs contract and force the semen through the duct system and urethra. This process is called ejaculation. Each ejaculation can contain up to 500 million sperm.
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References. Male Reproductive.wmv Baggaley, A. (2001) Human Body. London: Dorling Kindersley. Seely, R. et al. (1989) Anatomy and Physiology. USA: TimesMirror/MosbyCollege. Tortora, G. and Grabolski, S. (1993) Principles of Anatomy and Physiology. USA: HarperCollins. Tucker, L. (2002) Anatomy and Physiology. Cambridge: Holistic Therapy. 4/29/2015 Clare Hargreaves-Norris 13
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4/29/2015 Clare Hargreaves-Norris 15 Ovaries DescriptionFunction The ovaries are 2 oval- shaped organs that lie to the upper right and left of the uterus. Each ovary measures about 4 to 5 centimeters in a grown woman. After puberty one ovum is released each month. This process is called ovulation. The ovaries produce, store, and release ova into the fallopian tubes in the process called ovulation. The ovaries are also part of the endocrine system because they produce the female sex hormones estrogen and progesterone. These hormones are responsible for female secondary sexual characteristics.
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4/29/2015 Clare Hargreaves-Norris 17 Follicle. Small structures on the surface of the ovaries. The follicles contain fluid and an ovum. When an ovum is mature for fertilisation the follicle splits to release the ovum. The mature ovum then travels along the Fallopian tube to the uterus.
4/29/2015 Clare Hargreaves-Norris 18 Fallopian tubes DescriptionFunction There are 2 Fallopian tubes, each attached to a side of the uterus. The Fallopian tubes are about 10centimeters long and about as wide as a piece of spaghetti. At the other end of each Fallopian tube is a fringed area, (fimbriae ends), that wrap around near the ovary. When an ovum exits an ovary, it enters the Fallopian tube. Once inside the Fallopian tube the ovum is transported towards the uterus by peristalsis and tiny hairs (cilia) in the tube's lining help push the ovum down the narrow passageway toward the uterus.
4/29/2015 Clare Hargreaves-Norris 19 Uterus DescriptionFunction The uterus is shaped like an upside-down pear. It has three layers: - Endometrium (mucus membrane – columna epithelial lining). - Myometrium (thick smooth muscle – thickest in the body). - Perimetrium (serous membrane). Receives the fertilised ovum which develops in the uterus. The uterus grows with the foetus until birth. The muscle expands and contract to accommodate a growing foetus. The muscle helps to push the baby out during labour.
4/29/2015 Clare Hargreaves-Norris 20 Vagina DescriptionFunction The vagina is a muscular, hollow tube that extends from the labia to the uterus. Muscular walls enable it to expand and contract. This allows the vagina to accommodate something as wide as a baby. The vagina's muscular walls are lined with mucous membranes. Lubricating fluids keep the vagina protected, moist and assist with penetration. The vagina serves 2 purposes: It is where the penis is inserted during sexual intercourse. It is the pathway that a baby takes out of a woman's body during childbirth.
4/29/2015 Clare Hargreaves-Norris 21 External genitalia DescriptionFunction Mons pubis: The fleshy area located above the top of the vaginal opening. Labia (Major and Minor): Two pairs of skin flaps that protect the external genitalia and urethral orifice. Clitoris: Small sensory organ located toward the front of the vulva where the folds of the labia join. Mons pubis and labia protect the internal structures such as the clitoris.
4/29/2015 Clare Hargreaves-Norris 22 Mammary glands DescriptionFunction The mammary glands are located in the breasts. They consist of 15-20 glandular lobes. Inside each lobe are several smaller lobules. The mammary glands act as reservoirs for the milk. They secrete the milk when stimulated during lactation.
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4/29/2015 Clare Hargreaves-Norris 25 Menstruation When a baby girl is born, her ovaries contain hundreds of thousands of ova. The ova remain inactive until puberty begins. At puberty the pituitary gland starts making hormones. The hormones stimulate the ovaries to produce female sex hormones, including oestrogen. The secretion of these hormones causes a girl to develop into a sexually mature woman.
4/29/2015 Clare Hargreaves-Norris 26 Mensturation flows. Towards the end of puberty, girls begin to release ova as part of the menstrual cycle. Approximately once a month, during ovulation, an ovary sends a tiny ovum into one of the fallopian tubes. Unless the egg is fertilised by a sperm while in the fallopian tube, the progesterone levels drop causing the egg to dry up. The dried up ovum leaves the body about 2 weeks later through the uterus. This process is called menstruation. Blood and tissues from the endometrium of the uterus combine to form the menstrual flow. This which usually lasts from 3 to 5 days. On average, the monthly cycle for an adult woman is 28 days, but this may range from 23 to 35 days.
4/29/2015 Clare Hargreaves-Norris 27 Dysmenorrhoea. Painful periods. Many women also experience abdominal cramps during the first few days of their period. These are caused by prostaglandin, a chemical in the body that makes the smooth muscle in the uterus contract.
4/29/2015 Clare Hargreaves-Norris 28 Fertilisation Sexual organs of both sexes are required for reproduction. The female ovaries produce female gametes (ova). The male testes produce male gametes (sperm). Natural fertilisation occurs after sexual intercourse when the penis deposits seminal fluid into the vagina. The sperm have a tendency to swim towards the fallopian tube containing the ovulated ovum due to chemical signals that the sperm respond to. They are also assisted in their journey by the cilia that are located in the cervix, wafting them along. Once the sperm fuses with the ovum, the ovum membrane adjusts to prevent any other sperm from entering. Zygote is the name given to a fertilised ovum. The zygote develops into a foetus. Pregnancy will develop over a 40 week period.