Download الشريحة 1

Basic Concepts of animal development:
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Fertilization: Fusion between egg and sperm.
Cleavage: Rapid cell multiplication of zygote.
Blastulation: Ball of cells lined by blastoderm and
enclosed with blastocoele cavity.
Gastrulation: Rapid cell movement of blastula cells
leading to formation of germ layers; ectoderm ,
mesoderm & endoderm.
Neurulation & Formation of organ rudiment:
Formation of primitive organ rudiments.
Organogenesis: Formation of organs
Embryonic Development
Kinds of Embryo Axis
• Superior or cranial and inferior or caudal : Used to determine the
relationships to the head and tail respectively.
• Frontal or coronal section: Any vertical plane that intersects the
median plane at right angles and divides the body into front (anterior
or ventral ) and back (posterior or dorsal).
• Sagital or mid-sagital section: Any vertical plane passing through
the body that is parallel to the median plan.
• Median plane : This is imaginary vertical plane of the section that
passes longitudinally through the body.
• Lateral and medial plane : Refer to the structures that are
respectively farther from or nearer to the median plane of the body.
• Transverse or horizontal section: Any plane that is at right angles
to both the median or coronal planes.