EMBRYONIC DEVELOPMENT

OVERALL IDEAS DEVELOPMENT BEGINS AFTER FERTILIZATION OF THE EGG BY THE SPERM ZYGOTE IS DEFINED AS A FERTILIZED EGG CELLS BECOME MORE DIFFERENTIATED AS THE STAGES OF DEVELOPMENT CONTINUE THE ZYGOTE WILL NOW GO ON TO DEVELOP INTO AN EMBRYO AND EVENTUALLY A FETUS

STAGES OF EMBRYONIC DEVELOPMENT CLEAVAGE BLASTULA FORMATION GASTRULA ORGANOGENESIS EVENTUALLY BIRTH

Our Journey begins at FERTILIZATION-DESCRIBE WHAT HAPPENS HERE?

FERTILIZATION FUSION OF SPERM AND THE EGG A ZYGOTE IS FORMED HAPLOID IS NOW DIPLOID (46 CHROMOSOMES) NOW WE CAN DEVELOP

STAGE 1-CLEAVAGE: DESCRIBE WHAT HAPPENS HERE?

STAGE 1-CLEAVAGE RAPID MITOTIC CELL DIVISION  MAKING MORE CELLS FOR THE INDIVIDUAL NO CELL GROWTH ALL CELLS ARE EMBRYONIC NOT DIFFERENTIATED  NO FATE YET. CAN FORM INTO ANY CELL TYPE THIS STAGE IS WHERE THE ORGANISM IS CONSIDERED AN EMBRYO

STAGE 2-BLASTULA FORMATION- WHAT HAPPENS HERE?

STAGE 2- BLASTULA STAGE ROUND HOLLOW BALL OF WITH A SINGLE LAYER OF CELLS. FLUID FILLED WITH CYTOPLASM CELLS CONTINUE TO DIVIDE

STAGE 3-GASTRULATION

STAGE 3 GASTRULATION INDENTATION OF BLASTULA FORMS 3 DISTINCT LAYERS  ECTODERM: DEVELOPS SKIN,LINING OF ORGANS  OUTER  MESODERM: DEVELOPS MUSCLES,NERVOUS SYSTEM,BLOOD,BONE  MIDDLE  ENDODERM: DEVELOPS INNER SYSTEMS (DIGESTIVE,RESPIRATORY)  INNER

ORGANOGENESIS

STAGE 4 ORGANOGENESIS CELLS OF THE LAYERS NOW HAVE A FATE  DIFFERENTIATED. CAN NOT FORM ANY CELL TYPE THEY WANT.THEY NOW HAVE A JOB LAYERS DEVELOP INTO TISSUES AND ORGANS

FULL GASTRULATION OF EMBRYO MOVING INTO A FETUS

HOW DOES THIS IMPACT PREGNANCY? 0-3 MONTHS  ZYGOTIC/EMBRYONIC STAGE  CLEAVAGE/BLASTULA 3-6 MONTHS  GASTRULA AND SOME ORGAN DEVELOPMENT 6-9 MONTHS  FURTHER ORGAN DEVELOPMENT, MATURITY,AND FUNCTION ~9 MONTHS  FETUS IS BORN

FETUS IN UTERO(IN UTERUS) CERVIX UMBILICAL CORD PLACENTA AMNIONIC SAC OVIDUCT UTERUS

IMPORTANCE OF PLACENTA CONTAINS A NETWORK OF BLOOD VESSELS WHICH SUPPLY THE FETUS WITH OXYGEN AND NUTRIENTS JOINS WITH THE UMBILICAL CORD TO SUPPLY THE FETUS WITH NEEDED NUTRIENTS

THOUGHT QUESTION WHY ARE EMBRYONIC STEM CELLS SUCH A HOT TOPIC IN SCIENCE?

IDEAS TAKING EMBRONIC STEM CELLS CAN HELP MAKE ANY TYPE OF CELL  NOT FATED RESULTS IN GROWING OF NEW TISSUES OR PERHAPS ORGANS PROBLEM IS TAKING IT FROM AN UNBORN CHILD