Introduction to embrylogy
Lecturer Dr. Firdous M. Jaafar
HHDTD Module
Objectives
1- Define Embryology
2- Evaluate the importance of studying
embryology.
3- Define some terms of embryology.
Embryology
From a single cell to a baby in 9 months,
a developmental process that represents an
amazing integration o f increasingly complex
phenomena. The study o f these phenomena
is called embryology
Why we study embryology?
• 1- provide knowledge essential f o r creating
health care strategies for better reproductive
outcomes.
• 2- help in prenatal diagnoses and treatments.
• 3- provide mechanisms to prevent birth
defects, the leading cause o f infant mortality.
Terminology of Embryology
• Gametes are derived from primordial germ
cells (PGCs)
• 1- Male gamete: is the sperm.
• 2- Female gamete: is the oocyte.
• Gametogenesis: is the process of meiosis in
the germ cells
• fertilization, the process by which the male
gamete, the sperm , and the female gamete,
the oocyte , unite to give rise to a zygote.
Oocyte
Sperm
Terminology in embryology
• Follicle: is an oocyte that surrounded by
epithelial(follicular) cells.
• Ovulation: is the process of release of oocyte
after rupture of follicle, under the effect of LH
hormone.
• Cleavage: is a process of mitotic divisions of
the zygot to produce small blastomeres.
Terminology of embryology
• Morula : is a 16 cell stage of division of
embryo.
• Blastocyst: Is a structure formed when a
cavity(blastocele) is formed within the inner
cell mass of morula.
Morula, and Blastocyst
Terminology of embryology
1-Trophoblast;: is the part of embryo which
will form placenta.
a- cytotrophoblast
b-syncytiotrophoblast.
Terminology of embryology
• Germ layers of the embryo:
• 1- Ectoderm.
• 2- Mesoderm
• 3- Endoderm.
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