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,BONEMIDDLE

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