Hereditary influences on development

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Hereditary influences on development

  1. 1. HUMAN GROWTH AND DEVELOPMENT SSYM 1023
  2. 2. HEREDITERY INFLUENCES ON DEVELOPMENT
  3. 3. PRINCIPLES OF HEREDITERY TRANSMISSION We must start at conception to understand the working of hereditery.  Ovum released by a women’s ovary and on its way to the uterus via the fallapion tube .  Then fertilized by a man’s sperm.
  4. 4. THE GENETIC MATERIAL • Sperm cell begins to disintegrate and releasing genetic material. • Ovum also release genetic material. • New cells nucleus (zygote) forms which contain hereditery • Zygote is about 1/20th the size of the head of pin.
  5. 5. What hereditery material is present in human zygote? • Hereditery information provided by the father’s sperm n the mother’s ovum. • Contains 46 elongated threadlike bodies called chromosomes.
  6. 6. M Genetic XY Genetic XX
  7. 7. GROWTH OF THE ZYGOTE AND PRODUCTION BODY CELLS Zygote moves through fallopian tube Towards uterus Begins to replicate itself through process of mitosis
  8. 8. Zygote divides into two cells, then become four, become eight, become sixteen and so on. New cells with has identical 23 pairs of chromosomes(46 in all). Same genetic material as the original cell. Makes up muscles, bones, organs and other bodily structures.
  9. 9. Male germ cells in the testes produce sperm. Female germ cells in the ovaries produce ova. Undergo meiosis process. Crossing over takes places
  10. 10. DOMINANT TRAITS RECESSIVE TRAITS Dark hair Blown hair Full head of hair Pattern baldness Curly hair Straight hair Facial dimples No dimples Normal vision Color blindness Normal blood clotting Haemophilia Normal blood cells Sickle-cell anemia
  11. 11. EXAMPLE:
  12. 12. HEREDITERY UNIQUENES: MULTIPLE BIRTH • Two people share a genotype. • A zygote split into separate but identical cells. • Called as monozygotic ( or identical twins) because developed from a single zygote and have identical genes. • Occurs in 1 of of every 125 births.
  13. 13. SOURCES OF CONGENITAL DEFECTS Congenital defects Inherited defects Chromosomal abnormalities Too many 0r too few chromosomes Broken or damaged or chromosomes Environmental defects Genetic abnormalities Recessive genes for a disorder Dominant genes for a disorder Genetic mutation Prenatal exposures to damaging effects Complications of the birth process
  14. 14. Four common sex chromosomes abnormalities Female abnormalities Male abnormalities TURNER’S SINDROME KLINEFELTER’S SYNDROME ( XO) ( XXY, XXXY ) 1 in 2500 births 1 in 750 births POLY-X or “SUPERFEMALE” SYNDROME SUPERMALE SYNDROME ( XXX, XXXX, XXXXX ) 1 in 1000 births 1 in 1000 births ( XYY, XYYY, XYYYY )
  15. 15. Mentally retarded Once in every 800 births Slopping forehead, protruding tongue, Extra at 21st chromosomes -IQ average is 55 -normal children is 100 characteristics short stubby Slightly flattened nose, and almond-shaped nose. Congenital eye, ear and heart defects
  16. 16. Diabetes Cystis fibrosis (CF) hemophilia MAJOR RECESSIVE HEREDITERY DISEASES Duchennetype muscular dystrophy Phenylketonuria ( PKU ) Tay-Sachs disease Sickle-cell anemia

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