Transcript
EMBRYOLOGY Study of developmental process amazing integration of increasingly complex
phenomenon EMBRYOGENESIS (Organogenesis)
period of first eight (08) weeks from a single cell to establishing organ primodia.
FOETAL PERIOD from 9th week to birth in which differentiation
continues while foetus grows and gains weight.
REPRODUCTION OF CELLS
Meiosis and cyto differentiation Reduce number;diploid (46 ) to haploid (23) Alteration in shape of germ cells
Fertilization of spermatozoa and oocyte Zygote formation
Somatic cell: 23 pair or diploid chromosome
22 pair of matching chromosome “autosome”
One pair of “sex chromosome” XX--genetically female XY-- genetically male
Pairs not in proximity closer in meiotic division
CELL DIVISIONInterphase – Between
G1;1 to several hrs Respond to growth factors
S; 6-8 hrs DNA replication
G2; 2-4 hrs Preparing for division
Mitosis: (1 – 2hrs)
Prophase – Before Metaphase – After Anaphase – So much Telophase – End of relationship.
MEIOSIS (DECREASE IN NUMBER)Meiosis-1 (HETEROTYPICAL) Prophase
Leptotene Stage (RIBBON) Zygotene Stage (YOLKED TOGETHER) Pachytene Stage (THICKNESS) Diplotene Stage ( DOUBLE) Diakinesis Stage
Metaphase 1 Anaphase 1 Telophase 1Meiosis-2 (HOMOTYPICAL)
SIGNIFICANCE OF MEIOSIS
1. Haploid number of chromosomes2. Half the amount of DNA3. Genetic Variability
1. Cross overs2. Random distribution
Crossovers Chiasma formation
THANK YOU
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