This document provides definitions and explanations of key terms in developmental anatomy and embryology. It discusses the early views of embryology in ancient Egypt, India, Greece and the Quran. Some key points covered include the definition of an embryo, fetus, conceptus and zygote. Gestation periods and the trimesters of pregnancy are defined. Fertilization, implantation and parturition processes are summarized. Terms regarding male and female reproductive anatomy and gametes are also defined.

1. EMBRYOLOGY
INTRODUCTION
Dr. Hina Khan
Assistant Professor
Anatomy

2. Objectives
Definition of Developmental
Anatomy
Brief history of Developmental
Anatomy
Nomenclatures in
developmental Anatomy

3. Embryology in the Middle Ages
Holy Quran (seventh century AD), mentions that
human beings are produced from a mixture of
secretions from the male and female. Several
references are made to the creation of a human
being from a nutfa (small drop). It also states that
the resulting organism settles in the womb like a
seed, 6 days after its beginning.

4. Ancient Views of Human Embryology
 Egyptians approximately 3000 B. C., knew of methods for
incubating birds' eggs, but did not produce record.
 Sanskrit treatise Hindi holy book also describes ancient
ideas concerning the embryo.
 Greek scholars made many important contributions to the
science of embryology.
 The first recorded embryologic studies are in the books of
Hippocrates of Cos, the famous Greek physician (circa
460-377 B. C.), who is regarded as the Father of Medicine.
He explained the developed of embryo.

5. Terms

6. Developmental Embryo
It is the field of embryology
concerned with the changes that
cells, tissues, organs, and the body as a
whole undergo from a germ cell of
each parent to the resulting adult.

7. Trait
Any genetically determined
characteristics is called trait

8. HOMOZYGOTE
Relating to a cell that has two identical
alleles for a particular trait at
corresponding positions on homologous
chromosomes.

9. Heterozygote
An individual having different alleles at a
given locus on the homologous
chromosomes is called heterozygote

10. Dominant Triat
A trait expressed in the homozygous as
well as in the heterozygous

11. Recessive triat
A trait expressed only in the heterozygote

12. Genotype
The genetic constitution of an organisum

13. Phenotype
The observable characteristics of an
individual

14. Gene Expression
A process by which the information
contained in the gene is converted to
molecules that determine the properties
of cells.

15. Replication
Production of exact copy of strand of
DNA or (RNA)

16. Transcription
In which the Single strand of RNA is
synthesized from double strand of DNA

17. Translation
The conversion of genetic information
contained in RNA in to (protein)
polypeptide chain

18. In Vivo – In Vitro
In Vitro: any
sequence of
events occur
outside the body
In Vivo: any sequence
of events occur inside
the body

19. Oocyte (L. ovum, egg)
The female germ or sex
cells are produced in
the ovaries. When
mature, the oocytes are
called secondary
oocytes or mature
oocytes.

20. Ovaries
Paired female internal
Reproductive organs,
present near the
Uterus

21. Uterus
Female Internal
Reproductive
organ, divided into:
 Fallopian Tubes
 Body of Uterus
 Cervix

22. Fallopian Tubes
 They are tube like
structures, lying near
to the ovaries, help in
the transport of ovum,
Fallopian tube divided
into four parts
 This tube is also site
for the fertilization of
Ovum by male gametes
the “sperms”

23. Male Gametes
Male Gametes are
called as sperms,
they are produced
in the seminiferous
tubules of testis

24. Testes
 Paired male internal
genitilia present in the
scrotum outside the body
 Containing seminiferous
tubules which provide the
male gametes

25. Fertilization
Male gametes produced by
the Seminiferous tubules
of testis, deposited into
female genital tract and
only one penetrate the
ovum in the ampulla of
fallopian tube to form the
Zygote

26. Zygote.
This cell results from
the union of an oocyte
and a sperm during
fertilization. A zygote
or embryo is the
beginning of a new
human being.

27. Embryo (Gr. embryon)
 The developing human during its
early stages of development.
 The embryonic period extends to
the end of the eighth week (56
days), by which time the
beginnings of all major
structures are present.

28. Size of Embryo
The size of embryos is
given as crown-rump
length, which is measured
from the vertex of the
cranium (crown of head) to
the rump (buttocks).

29. Fetus (L., unborn offspring)
 From 9th week to 40th week of
gestational age or 11th week to
38th week after fertilization the
developing baby is called as the
fetus.
 During the fetal period (ninth
week to birth), differentiation and
growth of the tissues and organs
formed during the embryonic
period occur.

30. Conceptus
 Conceptus (L. conceptio,
derivatives of zygote). The
embryo and its adnexa (L.,
appendages or adjunct
parts) or associated
membranes (i.e., the
products of conception).
 The conceptus includes all
structures that develop
from the zygote, both
embryonic and
extraembryonic.

31. Implantation
The process during which the
blastocyst attaches to the
endometrium, the mucous
membrane or lining of uterus,
and subsequently embeds in it.
The preimplantation period of
embryonic development is the
time between fertilization and
the beginning of implantation, a
period of approximately 6 days.

32. Age of Developing Baby
Gestational Age: the age of
baby from the first day of
last menstrual cycle to the
birth of bay. It is about 40
weeks or 10 lunar months or
380 days.
Fertilization Age: age of
baby after the fertilization up
to birth of baby. It is 38
weeks or 366 days. It is two
week shorter than the
gestational age.

33. Trimester
 The entire pregnancy
divided into three
trimesters, each trimester
consists of three moths.
 The first trimester is very
important in which most of
organs of embryo
developed.
 In second and third
trimester of pregnancy the
differentiation and
morphogenesis of already
formed organs will occur

34. Postnatal Period
The period
occurring after
birth. Explanations
of frequently used
developmental
terms and periods
follow.

35. Abortion (L. aboriri, to miscarry)
 A premature stoppage of
development and expulsion of a
conceptus from the uterus or
expulsion of an embryo or fetus
before it is viable-capable of living
outside the uterus.
 Abortion occurs before the fetus
becomes viable that is before the six
months of development

36. Premature
 Birth of baby, usually
after six months.
 Baby can survive by
keeping in an incubator
by providing the
artificial respiration
 The survival rates
depends upon the age
of fetus

37. Parturition
 It is the process
of birth of baby
through the birth
canal of woman