2 Learning Objectives(1/3) Outline the general structure of the reproductive system (Male & Female)State the functions of the main parts of the reproductive systemOutline the role of meiosis to produce sperm & ova (egg) cellsDefine the term secondary sexual characteristicsOutline the role of oestrogen, progesterone & testosteroneOutline the nature of birth control to include natural, mechanical, chemical and surgical methodsState the location of fertilisation
3 Learning Objectives(2/3) Outline the events & outline the role of oestrogen and progesterone of the menstrual cycleExplain copulationOutline infertilityState one cause of male infertilityState the availability of corrective measures for male infertilityState one cause female infertilityState the availability of corrective measures for female infertility
4 Learning Objectives(3/3) Explain implantation, placenta formation & functionOutline the birth processExplain In-vitro fertilisation & implantationOutline milk production & breastfeeding including biological benefits
7 Testes A gonad is an organ that produces sex cell in animals. Male gonads are called testesTestes develop inside the body at first, but a few weeks before birth descend into the scrotum.This means they are kept at slightly lower than body temperature (35°) which is the ideal temperature for sperm production.
8 TestesSeminiferous tubules inside the testes are lined with sperm producing cells.Cells between the tubules produce the hormone testosterone.
9 Internal structure of testes Seminiferous tubuleSperm producing cells (2n)SpermSertoli cell – nourishes spermBlood capillaryInterstitial cells – produce testosterone
10 EpididymisAll the seminiferous tubules join to form the epididymis.Sperm mature and are stored here.
11 Sperm duct and urethraThe epididymis leads to the sperm duct (vas deferens)The sperm duct brings sperm to the urethra.The urethra is responsible for carrying sperm and urine out of the body
12 Glands in the male reproductive system Seminal VesicleProstate GlandCowper’s GlandThese glands produce seminal fluid which nourishes the sperm and provides a medium in which to swim.Seminal fluid + Sperm = Semen
13 Bladder Seminal Vesicle Prostate gland Cowper’s Gland Penis Sperm duct Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisProduces1. Sperm 2 Testosterone
14 Bladder Seminal Vesicle Prostate gland Cowper’s Gland Penis Sperm duct Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisStores sperm
15 Bladder Seminal Vesicle Prostate gland Cowper’s Gland Penis Sperm duct Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisCarries sperm from the epididymis to the urethra
16 Produces Seminal Fluid - For sperm to swim in - Nourishment for sperm Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisProduces Seminal Fluid - For sperm to swim in - Nourishment for sperm
17 Tube through which the sperm travel through the penis Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisTube through which the sperm travel through the penis
18 Keeps testes at a lower temperature Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisKeeps testes at a lower temperature
19 Places sperm in the females body Functions of the main parts of the Male reproductive systemTestisEpididymisSperm ductSeminal VesicleProstate glandBladderUrethraScrotumCowper’s GlandPenisPlaces sperm in the females body
20 Seminal vesicles, Cowper’s gland and Prostate gland Summary of functions of main parts of male reproductive systemPartFunctionTestisProduces sperm and testosteroneEpididymisMatures and stores spermSperm ductCarries sperm from the epididymis to the urethraSeminal vesicles, Cowper’s gland and Prostate glandProduces seminal fluid which feeds the sperm and allows them to swim. Sperm and seminal fluid are collectively called semen.UrethraAllows the passage of either urine or sperm.PenisPlaces sperm inside the body of a femaleScrotumKeeps testes at a lower temperature (35°). This is the optimum temperature for Meiosis to occur.
22 Sperm Structure Acrosome (contains digestive enzymes) Head Nucleus (contains 23 chromosomes)Collar (contains mitochondria)MiddleFlagellum (allows sperm to swim)Tail
23 Role of meiosis in sperm and egg production Sperm and egg producing cells are diploid i.e. they contain 46 chromosomes.They divide by meiosis to form sperm and egg cells.Each sperm and egg cell, therefore, has a haploid number of chromosomes i.e. they have 23 each
24 Role of meiosis in sperm and egg production As both a sperm nucleus and an egg nucleus are haploid they combine in fertilisation to form a diploid zygote i.e. the new zygote has 46 chromosomes.23 chromosomes + 23 chromosomes = 46 chromosomesThe zygote now grows by mitosis division ensuring that each new cell has a diploid number of chromosomes.
26 Male Hormone - Testosterone Testosterone is the male hormone responsible for the development of the primary and secondary male sexual characteristicsThe primary sexual characteristics are the presence of the male and female reproductive partsSecondary sexual characteristics refer to features that distinguish males from females, apart from the sex organs themselves
27 Male Secondary Sexual characteristics The growth of pubic, facial and body hairThe enlargement of larynx and ‘breaking’ of the voiceIncreased muscular development and bone developmentA growth spurt at pubertyAn increased secretion of sebum in the skin
29 The OvaryThese produce the eggs and female hormones.All the eggs in an ovary are present at birth.After puberty 20 eggs mature each month. Only one will be released from the ovary – the rest will die.
30 The Fallopian tube (oviduct) The Fallopian tubes are muscular and approx 12cm long.Funnels at the tip of each tube catch the egg after it is released from the ovary.The egg is moved along the tube by cilia and muscular peristalsis.The egg is either fertilised or dies in the fallopian tube.
31 The Uterus (womb)Muscular structure approximately the size of your fist.Outer wall made of involuntary muscle.Inner lining is called the endometriumThis lining thickens each month with cells and blood vessels to nourish the embryo.The cervix separates the uterus from the vagina.
32 The vaginaElastic muscular tube 10cm long.Allows entry of sperm.Is the birth canal for the exit of a baby.Lined with cells that produce mucous. This serves to protect against the entry of pathogens.
33 Fallopian tube (Oviduct) Structure of the Female reproductive systemFallopian tube (Oviduct)FunnelOvaryOvarian LigamentUterusLining of uterus (endometrium)CervixWall of uterusVaginaVulva
34 Fallopian tube (Oviduct) Functions of the main parts of the female reproductive systemFallopian tube (Oviduct)FunnelOvaryOvarian LigamentUterusLining of uterus (endometrium)CervixWall of uterusVaginaProduces :EggOestrogenProgesteroneVulva
35 Fallopian tube (Oviduct) Functions of the main parts of the female reproductive systemFallopian tube (Oviduct)FunnelOvaryOvarian LigamentUterusLining of uterus (endometrium)CervixWall of uterusVaginaCatches the egg after release from ovaryTransports egg from ovary to wombSite of fertilisationVulva
36 Fallopian tube (Oviduct) Functions of the main parts of the female reproductive systemFallopian tube (Oviduct)FunnelOvaryOvarian LigamentUterusLining of uterus (endometrium)CervixWall of uterusVaginaImplantationHold foetusForms placentaVulva
37 Fallopian tube (Oviduct) Functions of the main parts of the female reproductive systemFallopian tube (Oviduct)FunnelOvaryOvarian LigamentUterusLining of uterus (endometrium)CervixWall of uterusVaginaVulvaAllows entry of sperm into female systemBirth canal to allow exit of baby
38 Summary of functions of main parts of female reproductive system OvaryTo produce the egg (ova). To produce the hormones oestrogen and progesteroneFallopian tube(oviduct)Catches the egg from the ovary and transports it to uterus. Site of fertilisation.UterusSite of implantation. Holds the developing embryo. Has a lining (endometrium) enriched with blood vessels to nourish the embryo.Forms the placenta.VaginaAllows entry of sperm and exit of baby at birth.
39 Female Hormones Oestrogen and progesterone are the female hormones A combination of oestrogen and progesterone at puberty causes the development of the secondary female characteristics:The maturing and enlargement of the breasts.The widening of the pelvis to allow for birth.The growth of pubic and underarm hair.A growth spurt.
40 The OvaryThe ovaries produce the eggs and the female hormones oestrogen and progesterone.The ovaries of a female foetus contains all the potential eggs at birth. These eggs have not yet divided by meiosis and as a result are diploidAfter puberty a number of eggs are produced by meiosis each month. Usually only one egg continues to grow … the rest die
41 The OvaryOnce meiosis is complete the egg is surrounded within a structure called the Graafian follicle.This structure produces the female hormone oestrogenWhen mature the follicle forms a swelling on the outside of the ovary. It bursts at ovulation to release the eggAfter ovulation the follicle fills with yellow cells and becomes the Corpus luteum (yellow body).This secretes the hormone progesterone
42 The Menstrual CycleThe menstrual cycle is a 28 day sequence of events that produces an egg and prepares the body for pregnancy.This cycle begins at puberty and continues until the menopause (the end of the woman’s reproductive life).Summary of events in the menstrual cycleDays 1 – 5The old lining of the uterus (endometrium) breaks down and is shed from the body. The loss of this blood and tissue is called menstruation (period).A new egg is produced in the ovary by meiosis. This new egg is surrounded by the Graafian follicle.
43 The Menstrual CycleDaysThe hormone oestrogen is produced by the developing Graafian follicle. This has two functions:- It causes the lining of the uterus (endometrium) to build up again in preparation for implantation.- Oestrogen also prevents the development of any more eggs.Day 14Ovulation. This occurs when the Graafian follicle bursts to release the egg into the fallopian tube.
44 DaysThe Graafian follicle now develops into the Corpus Luteum (yellow body). This has two functions:- It causes the endometrium to thicken even further.- It also prevents new eggs from forming.The egg that was released will die by day 16 if it is not fertilised. Thus days 12 – 16 of the menstrual cycle are referred to as the Fertile Period.(Even though the egg is not released until day 14, sperm, which can survive for a period of time in the female body, may already be present. Thus the fertile period begins on day 12).
45 If fertilisation does not take place the Corpus Luteum starts to degenerate around day 22. This results in a reduction in progesterone levels. As a result the lining of the uterus breaks down again on day 28. The menstrual cycle begins again with day 1.
46 If fertilisation has not occurred the cycle begins again with the breakdown of the endometrium. The Menstrual Cycle12345678910111213141516171819202122232425262728DAY 1-5 : Blood from the womb lining is shed from the bodyAfter day 5 the lining of the uterus repairs and builds up againFertile periodOvulation occurs on Day 14Implantation may happen
47 Inside the Ovary Developing Graafian follicle – secretes oestrogen Potential eggEgg is released from ovary (ovulation)Graafian follicle now changes to the Corpus luteum which secretes progesterone
48 Graafian follicle Corpus Luteum Hormones Endometrium 5 14 Days 28 Oestrogen________Progesterone _____Endometrium514Days28
49 Learning CheckName the main parts of the male reproductive system and give a function for each part named.Name the main parts of the female reproductive system and give a function for each part named.Outline what is happening on each of the following days of the menstrual cycle: 1,5,12,14,26?Outline the role played by oestrogen and progesterone in the cycle
50 Copulation – Sexual intercourse Sexual arousalThe penis becomes erectThe vagina becomes lubricatedCopulationThe penis is inserted into and moved inside the vaginaOrgasmSperm is released from the penis (Ejaculation)Contraction of vagina and uterus
51 Insemination Insemination is the release of sperm into the female Contractions of uterus and fallopian tubes move the sperm to the fallopian tubes within 5 minutesIf an egg is present it releases chemicals to attract the sperm this is called chemotaxis
52 FertilisationFertilisation is the fusion of the egg and sperm nuclei to form a diploid zygote.
53 Fertilisation usually occurs in the fallopian tube.
54 Fertilisation The acrosome releases enzymes to digest the egg membrane A number of sperm may reach the egg at the same time.The sperm loses its tail and the head enters the egg.The sperm and egg nuclei fuse to form a zygoteA chemical reaction at the membrane prevents other sperm cells entering.
55 ImplantationImplantation is the embedding of the fertilised egg into the lining of the uterusThis occurs days after fertilisation.By this time the zygote has grown into an embryo.During implantation a membrane called the amnion develops around the embryo. This secretes amniotic fluid which will surround the developing embryo and act as a shock absorber.After implantation the placenta forms.
56 Zygote Implanted embryo Implantation is the embedding of the fertilised egg into the lining of the uterus
57 Placenta FormationAfter implantation the embryo forms an outer membrane called a chorionThis chorion develops projections (chorionic villi) which, together with the blood vessels of the mother in the endometrium, form the placentaThe placenta allows nutrients, wastes, gases, antibodies and hormones to be exchanged between the blood of the mother and the embryo
58 Placenta Formation The blood of the mother and embryo do not mix This is important as:- The blood groups of mother and baby might not be compatible.- The blood pressure of the mothers system may cause damage to the embryo
59 Placenta Formation The placenta also makes the hormone progesterone The umbilical cord connects the placenta with the embryo. It contains blood vessels which circulate blood between the embryo and the placenta