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Human Reproductive System 1.1 – Sexual Reproduction • Define sexual reproduction • Define fertilization Mrs. Degl 1.2 - Sexual reproduction in humans • Identify and name on diagrams of the male reproductive system: • Identify and name on diagrams of the female reproductive system: • Describe fertilization • State process of early development an functions • Outline the growth and development of the • Outline the processes involved in labor and birth 1.3 - Sex hormones in humans • Describe the roles of testosterone and oestrogen • Describe the menstrual cycle Sexual Reproduction • Definition: – A process involving the fusion of the nuclei of two different gametes (sex cells) to form a zygote. – The production of offspring that are genetically different from each other. What are Gametes (sex cells)? • Simply: the sperm and the egg Female Reproductive System Mrs. Degl Male Reproductive System Ova Sperm Cell Gamete Production • Sperm – Millions • Eggs – much less – Humans – 1 – Mammals - 1-20 – Fish/ Amphibians – A lot Ovulation • Mature egg cells bursts into oviduct • Humans – once a month In the Beginning • When egg and sperm nuclei fuse they form a zygote. • Zygote is a single cell and eventually develops into an embryo. In the Beginning • The embryo is a ball of cells that implants into the wall of the uterus. Fertilization • Definition: – Fusion of gamete nuclei Fertilization • Definition: fusion of the nuclei from a male gamete (sperm) and a female gamete (egg) • Click me fertilization. Fertilization • Occurs in upper 1/3 of Oviduct • Only 1 sperm can fertilize an egg • Fertilized egg = zygote • An average woman is pregnant (gestational period) for 9 whole months. Fertilization Continued • After ovulation, egg caught in the funnel of the oviduct • Funnel lined with cilia to move it along • Muscles in the wall of the oviduct help move it by peristalsis Fertilization continued • Close to the top of the oviduct so sperm must meet it there • If the egg is not fertilized (824 hrs.) – it dies Implantation • Fertilized eggs are implanted into thick walls of uterus • Zygote grows into an embryo • Embryo gets air and nutrients through the umbilical cord • Mom’s uterus grows with the baby Placenta and Amnion • Placenta grows as embryo grows • Connects to wall of uterus • Where nutrients , gases, and excretory materials are exchanged Placenta and Amnion • Provides a barrier to toxins and pathogens • Some toxins like nicotine and pathogens like rubella virus, can pass across the placenta and affect the fetus Placenta and Amnion • Amnion surrounds the fetus • Makes liquid called the amniotic fluid • Helps support and protect the embryo Placenta and Amnion • After 11 weeks, embryo into a fetus • Placenta joined to fetus by umbilical cord with two arteries and a vein Ante-Natal Care (before birth) – Diet – calcium, iron, carbohydrates, protein – Exercise – swimming, walking – No smoking – Avoid diseases Birth 1st Trimester = 1st 12 weeks • Heart develops first • Neural tube develops • All body systems appear by Week 8 – Now a Fetus 2nd Trimester = up to 24 weeks • Most growth • Looks more like a baby • Some preemies survive at this stage 3rd Trimester = Up to 40 weeks • • • • • More growth Kicking, rolling, stretching Eyes open – Week 32 Lungs mature Rotates to head-down position, unless baby is breech Labor and Birth • Labor – Uterine contractions begin – Cervix dilates to 10 cm. Labor and Birth – Amniotic fluid breaks – Contraction of muscles in uterus walls – Dilation of the cervix – Passage through the vagina – Tying and cutting umbilical cord – Delivery of the afterbirth Sex Hormones • Testosterone • Estrogen Secondary Sexual Characteristics - Male • Produced by testosterone – Deeper voice – Chest and facial hair – Lengthen bones – Increased size of testes for sperm production Secondary Sexual Characteristics - Female • Induced by increased LH, FSH, estrogen, and progesterone hormone levels – Pubic hair – Widen pelvis – Enlarge mammary tissue (breasts) – Begin menstrual cycles