teratologyand embryology- common conditions during daily life activities may lead to teratological changeds during early weeks of pregnancy. If knowledge is given it can be easily prevented!

1. TERATOLOGY &
EMBRYOLOGY
BY
DR. ABDUL WAHEED ANSARI
CHAIRPERSON &PROF. ANATOMY
RAK COLLEGE OF MEDICAL SCIENCES
2/6/2014
1

2. If normal embryology is disturbed
• It resulted in teratology. It is the study of
abnormal congenital development resulting in
defects and monsters.
• Teratogens can be mechanical, thermal, drug
induced, bacterial or viral induced or
radioactive induced.
2/6/2014
2

3. Cleft lip & cleft palate
2/6/2014
3

4. Cleft lip/palate is a congenital
deformity
• Caused by abnormal facial development
during gestation.
• A cleft is a fissure or opening—a gap.
• It is the non-fusion between the frontonasal
process with the maxillary processes.
• Approximately 1 in 700 children born have a
cleft lip and/or a cleft palate.
2/6/2014
4

5. Tutankhamen
• Egyptian pharaoh who
may have had a slightly
cleft palate according to
diagnostic imaging.
• The research also showed
that the Tutankhamen
had "a slightly cleft
palate" and possibly a
mild case of scoliosis, a
medical condition in
which a person's spine is
curved from side to side.
2/6/2014
5

6. During the first six to eight weeks of
pregnancy
• Embryo's head is formed, & Five prominences
grow:
• One from the top of the head down towards the
future upper lip; (Frontonasal Prominence)
• Two from the cheeks, which meet the first
prominence to form the upper lip; (Maxillary
Prominence)
• Just below, two additional prominences grow
from each side, which form the chin and lower
lip; (Mandibular Prominence)
2/6/2014
6

7. 2/6/2014
7

8. The fertilized egg starts dividing
• A ball of cells get accumulated within the zona
pellucida and it enlarges and breakthrough the
zona liberating the cells to be rearranged in to
inner cell mass and outer cell mass.
• The outer cell mass give rise to trophoblastic cells
which penetrate the endometrium and anchors
the embryo to mother’s uterine wall.
• The inner cell mass forms the embryo blast or
formative cells.
• The germ disc is formed during second week,
bilaminar germ disc.
2/6/2014
8

9. The bilaminar germ disk on 12th day of
gestation
2/6/2014
9

10. The trilaminar germ disc
• The tall cells will be facing the amniotic cavity and
the cuboidal cells will form the roof of the yolk
sac cavity during second week of development.
• The gastrulation occurs during the third week of
development, the primitive streak is formed.
• The cells migrating from the surface embryoblast
after passing through the “pit” acquire the
features of mesoderm and make their presence
felt between surface ectoderm and endoderm.
2/6/2014
10

11. THE GASTRULATION
2/6/2014
11

12. Siamese twins are the conjoint twins resulting
from a single fertilized egg which has not
undergone complete division
• If the embryonic disc splits vertically in to two,
and grows further, then two maternal twins
will be the result of such development.
• If part of the embryonic disc does not
separated out and still it is one then the so
called Siamese twins or conjoint twins
develops; with two heads/or common
thorax/abdomen/or extra limbs/two backs
sticks together.
2/6/2014
12

13. Twins that are dicephalic parapagus have one trunk and two
heads
2/6/2014
13

14. Thoracopagus
2/6/2014
14

15. These twins share the abdomen regions
and organs
2/6/2014
15

16. Cephalopagus- they share their heads
2/6/2014
16

17. Craniopagus
• Craniopagus: Fused skulls, but separate bodies.
These twins can be conjoined at the back of the
head, the front of the head, or the side of the head,
but not on the face or the base of the skull.
• Cephalopagus: Two faces on opposite sides of a
single, conjoined head.
• These twins generally cannot survive due to severe
malformations of the brain.
2/6/2014
17

18. 2/6/2014
18

19. Archeology and teratology
• In Arabia, the twin brothers Hashim ibn Abd
Manaf and 'Abd Shams were born with Hashim's
leg attached to his twin brother's head.
• Legend says that their father, Abd Manaf ibn
Qusai, separated his conjoined sons with a sword
and that some priests believed that the blood
that had flown between them signified wars
between their progeny (confrontations did occur
between Banu al'Abbas and Banu Ummaya ibn
'Abd Shams in the year 750 AH).
2/6/2014
19

20. During early periods of gestation if
mothers are infected with
cytomegalovirus/mumps/measles
• It result in defects in brain development, holes
in their fetal hearts and abnormal
malformations.
• Microcephaly
2/6/2014
20

21. Fetal alcohol syndrome
• Fetal Alcohol Syndrome (FAS) is a pattern of
mental and physical defects which develops in
some unborn babies when the mother drinks too
much alcohol during pregnancy.
• A baby born with FAS may be seriously
handicapped and require a lifetime of special
care.
• Some babies with alcohol-related birth defects,
including smaller body size, lower birth weight.
2/6/2014
21

22. 2/6/2014
22

23. 2/6/2014
23

24. The effect of smoking during
pregnancy
• Babies born prematurely, babies born too
small, babies die before they can be born at
all.
• Cigarette smoke contains more than 4,000
chemicals.
• Nicotine and carbon monoxide work together
to reduce your baby's supply of oxygen.
• Nicotine chokes off oxygen by narrowing
blood vessels.
2/6/2014
24

25. 2/6/2014
25

26. The effect of thalidomide
• The birth defects includes extremely short or
missing arms and legs, missing ears (both
outside and inside), and deafness.
• There is also a risk of other problems such as
heart defects, missing or small eyes, paralysis
of the face, kidney
abnormalities, gastrointestinal
abnormalities, poor growth and mental
retardation.
2/6/2014
26

27. Thalidomide is a sedative agent
• It is now being used for treatment of several
medical conditions including leprosy, cancer,
and complications from HIV infection.
• In the late 1950's-1960's the thalidomide was
used by pregnant women in their first
trimester to treat nausea and vomiting caused
by morning sickness.
• It resulted in phocomelia, Amelia and other
birth defects.
2/6/2014
27

28. 2/6/2014
28

29. The radiation hazards
• Ionizing radiation is the kind of electromagnetic
radiation produced by x-ray machines, fluoroscopy, or
radiation therapy.
• Most diagnostic procedures expose the embryo to less
than 5 rad or 50 mSv.
• This level of radiation exposure will not increase
reproductive risks (either birth defects or miscarriage).
• According to published information, the reported dose
of radiation to result in an increased incidence of birth
defects or miscarriage is above 20 rad or 200 mSv.
2/6/2014
29

30. The embryo is very resistant to the
malforming effects of x rays during
• The first two weeks post conception or the
second two weeks from the last menstrual
period.
• The embryo is, however, sensitive to the
lethal effects of x rays, although doses much
higher than 5 rad or 50 mSv are necessary to
cause a miscarriage.
2/6/2014
30

31. From the third to the eighth week of
pregnancy
• The embryo is in the period of early embryonic
development but is not affected with either birth
defects, pregnancy loss, or growth retardation
unless the exposure is substantially above the 20
rad (200 mSv) exposure.
• From the eighth to the fifteenth week of pregnancy,
the embryo or fetus is sensitive to the effects of
radiation on the central nervous system.
2/6/2014
31

32. 8th week of pregnancy
2/6/2014
32

33. Beyond the 20th week of pregnancy
• The fetus is completely developed, it has
become more resistant to the developmental
effects of radiation.
2/6/2014
33

34. Patients who were exposed to
radiation in Hiroshima and Nagasaki
• After 50 years of studying this
population, there has been no demonstrable
increase in genetic disease.
2/6/2014
34

35. The Hot tubs and saunas can produce
NTD
• The type of birth defects that might arise
affect the brain and spine.
• These are called neural tube defects (NTD).
• Spina bifida is one example of a NTD.
2/6/2014
35

36. 2/6/2014
36

37. If a person drives for 2 hours
continuously
• Then his testicular temperature will be raised
by 2 degrees more and this will effect the
process of spermatogenesis.
2/6/2014
37

38. The common sources of formaldehyde
vapors
2/6/2014
38

39. Apart from dissection halls and
operation theaters
• Sources of Formaldehyde Gas are common
throughout most homes and can be steadily
off-gassed from lit cigarettes, particle board
storage cabinets, subflooring, carpeting,
wallboard, electronics, furniture, ceiling and
flooring materials, door casings, insulation,
and open stoves or heaters.
2/6/2014
39

40. The health effects of
formaldehyde
• Birth defects, fetal
abnormalities, spontaneous abortions, short
term miscarriages, and reduced fertility and
other negative pregnancy outcomes.
• It is a carcinogen.
• It effects spermatogenesis, sperm count is
reduced and abnormal sperms will be more.
2/6/2014
40

41. So teratology has a major role
• In different phases of life, influencing the
embryology.
• Every thing under the sun and including the
sun the teratogen effects influences the
embryology.
• Teratology and embryology are inseparable
entity.
2/6/2014
41

42. 2/6/2014
42