Sexual Reproduction in Human testis sperms ovary eggs (ova) zygote embryo foetus baby meiosis fertilization

Male Reproductive System testis epididymis vas deferens (sperm duct) Click here

Testes For production of male gametes (sperms) For production of male sex hormones Click here

Epididymis For temporarily storage of sperms During copulation, muscles of epididymis contract to release sperms Click here

Testis and epididymis sperm tubules epididymis vas deferens (sperm duct)

Male Reproductive System seminal vesicle prostate gland Cowper’s gland secrete seminal fluid

Functions of Seminal Fluid To provide a medium for the sperms to swim To activate and nourish the sperms To neutralize the acidity in the female reproductive tract

Male Reproductive System urethra penis

Penis Erected during copulation for insertion into vagina –Dilation of arterioles causes the erectile tissue of penis become turgid –Muscles of epididymis contract –Semen is squeezed from the penis to the top of vagina Ejaculation

The human penisThe human penis –Is composed of three cylinders of spongy erectile tissue During sexual arousalDuring sexual arousal –The erectile tissue fills with blood from the arteries, causing an erection

Female Reproductive System

Video of fertilization vagina cervix uterus oviduct ovary Click here

Functions of Ovary For production of female gametes (ova/eggs) For production of female sex hormones Click here

Oviduct Carries the ovum forward by –the beating action of the cilia on its inner surface –the contraction of muscles of oviduct Click here

Ovulation The release of an ovum from an ovary Video of ovulation Video of ovulation

Smaller (0.05mm) to reduce energy for movement to allow faster movement Larger (0.1mm) with large amount of food for early development of embryo Sperm (male)Ovum (female) Size Position of nucleus Movement In the headTowards centre Very active, moves by its tail Not able to move by itself Structure of human gametes

Sperm (male)Ovum (female) Shape Tadpole-like, with a head and a tail Spherical 0.05 mm 0.1 mm clear membrane plasma membrane cytoplasm nucleus follicle cells head nucleus tail Structure of human gametes II

Oogenesis is the development of mature ovaOogenesis is the development of mature ova

Spermatogenesis - making mature spermSpermatogenesis - making mature sperm

Oogenesis differs from spermatogenesis Oogenesis differs from spermatogenesis In three major ways…….……

First, during the meiotic divisions of oogenesisFirst, during the meiotic divisions of oogenesis –Cytokinesis is unequal, with almost all the cytoplasm monopolized by a single daughter cell, the secondary oocyte Second, sperm are produced continuously throughout a male’s life Second, sperm are produced continuously throughout a male’s life Which is not the case in oogenesis Which is not the case in oogenesis Third, oogenesis has long “resting” periods / arrested at certain stages Third, oogenesis has long “resting” periods / arrested at certain stages While spermatogenesis produces sperm in uninterrupted sequence While spermatogenesis produces sperm in uninterrupted sequence

when sexually stimulated, arterioles dilate and erectile tissue filled with blood, vas deferens testis soft penis not sexually stimulated penis becomes hard and erect Transfer of semen and fertilization

During copulation hard and erect penis muscles of epididymis contract inserts into vagina semen containing millions of sperms is ejaculated into the vagina Transfer of semen and fertilization

Menstrual Cycle Once in about 28 days The uterine lining becomes thickened 14 days after ovulation to prepare for the fertilized ovum to implant in it

Menstrual Cycle Day –Menstruation starts –Uterine lining decreases in thickness to a minimum Day –Lining becomes thicker with increased blood supply –Day 14 : ovulation Day –Lining remains thick to ready for implantation of fertilized ovum Day 28 –No implantation of fertilization ovum –Uterine lining breaks down; menstruation starts Video on change in uterine lining

Transfer of semen and fertilization 1sperms ejaculated into the vagina during copulation 2sperms swim through the cervix 3sperms swim up the uterus 4sperms meet the ovum in oviduct site of fertilization

female nucleus one sperm penetrates the egg membrane male nucleus fuses with the female nucleus clear membrane hardens; no other sperms can enter

20.7 The development of the human embryo 1ovum is released from ovary 2ovum fertilized by a sperm in oviduct 3zygote undergoes repeated mitotic cell divisions 4embryo implants into the uterine wall Stages leading to implantation pregnancy begins

Events Happened after Fertilization Ovum is fertilized at the oviduct Fertilized ovum is carried to the uterus by –the beating cilia on the inner wall of oviduct –the contraction of muscles of oviduct After reaching the uterus, the fertilized ovum fixed firmly onto the thick uterine wall  Implantation

Development of Human Foetus uterus foetus placenta umbilical cord amnion amniotic fluid Click here Video on foetus development

Functions of the Uterus During embryo development –Protect the embryo –Provide a constant environment for the embryo to develop –Allow placenta to attach on During birth of baby – Push the baby out by muscular contraction Click here

Functions of the Amniotic Fluid To keep the foetus moist to prevent dessication As a water cushion to –support the foetus –allow it to move freely –absorb shock –protect the foetus from mechanical injuries To reduce temperature fluctuation To lubricate the vagina during birth Click here

The Placenta oxygenated blood from mother’s artery villus umbilical vein umbilical artery deoxygenated blood to mother’s vein

After implantation uterus embryo embryonic villus which grows into the uterine wall blood capillaries of embryo mother’s blood space placenta temporary disc-shaped organtemporary disc-shaped organ allows exchange of materials between embryo & motherallows exchange of materials between embryo & mother connected to embryo via umbilical cordconnected to embryo via umbilical cord umbilical cord umbilical vein umbilical artery close contact

secretes amniotic fluid as embryo develops, amnion is formed After implantation uterus embryo protects embryo against shockprotects embryo against shock keeps a constant environmentkeeps a constant environment prevents desiccationprevents desiccation allows embryo to move easilyallows embryo to move easily amniotic fluid

Functions of the Placenta As a place of exchange of materials between mother and the foetus For secreting hormones

Adaptations of the Placenta Finger-like villi – to increase the surface area for efficient diffusion Maternal blood and foetal blood flows in opposite direction –to speed up diffusion of materials between them Maternal blood capillaries and foetal blood capillaries are separated by thin membrane –to shorten the distance of diffusion of materials

Adaptations of the Placenta Maternal blood is separated from foetal blood by capillary wall –to prevent high pressure of maternal blood to break the delicate foetal blood vessels –to prevent harmful substances to enter the foetus –to prevent clotting of maternal and foetal blood if their blood groups are incompatible Click here

      How is the baby born? foetus changes its position, so that the head is downward A few weeks before birth As birth approaches uterine muscles start to make rhythmic contractions  labour begins

How is the baby born? Birth process (3 stages) 1The dilation stage cervix dilates uterine & abdominal muscles contract amnion breaks amniotic fluid comes out abdominal muscles uterine wall amnion amnion fluid

How is the baby born? Birth process (3 stages) 2The expulsion stage muscular contractions push the foetus out (usually head-first) umbilical cord is tied and cut

How is the baby born? Birth process (3 stages) 3The placental stage placenta is pushed out of the body placenta (partially detached) uterus umbilical cord

The Birth Process Onset of labour –Uterine muscles begin to make rhythmic contractions –Contractions gradually become stronger and closer

The Birth Process Dilation of cervix allow the head of the foetus to pass through Uterine contractions causes amnion to break and amniotic fluid to escape out of the vagina Muscular contractions push the foetus head first through the vagina, and the umbilical cord is cut and tied Further contractions push the placenta out of the body –“After birth”

How is the baby born? baby begins to breathe a few seconds after being born After birth umbilical cord shrivels and falls away  a scar (navel) is left navel

Parental Care To increase the chance of survival of the young Mother feeds milk to the baby –Milk provides the babies with a balanced diet –It also contains antibodies which defend the babies against infection

Parental care Importance ensures better development of the babies increases the chance of survival of the young starts from suckling of the baby –milk is produced by mammary glands in breasts –milk contains antibodies which protect the babies from pathogens

Birth Control Human population increases exponentially –leads to storage of resources –problem of pollution becomes more serious –overcrowding

Contraceptive methods work by: 1 stopping sperms from meeting the ovum 2 preventing implantation of zygote rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD)

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) rhythm method restricts sexual intercourse until ‘safe period’ when no ovum is present in oviducts clues to when ovulation occurs –mucus secretions from cervix become more fluid –sudden rise in body temperature an unreliable method

Rhythm Method Prevent copulation during 7 days before and after ovulation (fertile period)

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) contraceptive pills contain synthetic hormones which prevent ovulation may have bad side effects

Contraceptive Pills Contains hormones which inhibit ovulation Must be taken regularly May have side effect

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) barrier methods 1condoms and female condoms a sheath of thin rubber  prevents sperms from getting into vagina often coated with spermicide  kills sperms

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) barrier methods 2diaphragm dome-shaped disc of thin rubber with a metal spring around it  prevents sperms from entering the uterus It should be used with spermicide.

Condom Male and female condom As a barrier to prevent sperms from entering the vagina

Diaphragm Fitted over the cervix To be used together with spermicides

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) surgical methods 1vasectomy cutting and tying the vas deferens of a man vas deferens on each side is cut and tied  sperms cannot be passed to the female body a permanent sterilization method

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) surgical methods 2tubal ligation cutting and tying the oviducts of a woman each oviduct is cut and tied ovary uterus  ovum and sperms can no longer meet a permanent sterilization method

Surgical Methods Vasectomy Cutting and tying of sperm ducts Tubal ligation Cutting and tying of oviducts

Contraceptive methods rhythm method contraceptive pills barrier methods surgical methods intra-uterine device (IUD) prevents implantation inserted into the female’s uterus by doctor

Concept Concept diagram Reproduction can be can be asexual reproduction sexual reproduction

Concept Concept diagram asexual reproduction can be by can be by binary fission budding vegetative propagation spore formation stem tuber bulbrhizomecormcutting by the formation of by the formation of artificially achieved by artificially achieved by

Concept Concept diagram in flowering plants in flowering plants male gamete flower copulation or IVF fertilization sexual reproduction forms forms female gamete in mammals in mammals pollination fertilization involves involves by by fusion is called and and after after for for

Concept Concept diagram copulation or IVF fertilization produces produces fertilization for for forms forms zygotefruit contains contains menstruationpregnancy if if fertilization fertilization occurs occurs if no if no fertilization fertilization occurs occurs menstrual cycle contraceptive methods seeds embryo new organism protect protect develops into develops into finally into finally into repeats in prevented by