NM702 MODULE 3: PRINCIPLES OF TERATOLOGY EXAM
QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS
VERIFIED LATEST UPDATE
What is a teratogen
A teratogen is any substance, organism, physical agent, or deficiency state present
during gestation that is capable of inducing abnormal postnatal structure or function
(biochemical, physiologic, or behavioral) by interfering with normal embryonic and fetal
development.
what are some substances that can act as teratogens?
-Infectious agents (such as toxoplasmosis, cytomegalovirus, syphilis), ionizing radiation,
hyperthermia, pesticides, metal (e.g., mercury and lead), organic solvents, excess or
deficient nutrients, effects of maternal chronic disorders (such as diabetes and
phenylketonuria), as well as over-the-counter, prescribed, and abused drugs. Some
herbal agents are also contraindicated in pregnancy, including those that have the
potential to act as abortifacients and/or uterine stimulants (black cohash, chamomile,
chasteberry, goldenseal, white horehound, licorice, mistletoe, nettle, pennyroyal, rue,
tansy, and yarrow).
-Heavy metals such as lead and mercury, organic solvents, alcohol, and ionizing
radiation are confirmed environmental teratogens, and exposure could contribute to
pregnancy loss
, Is it easy to identify a teratogen? Why or why not?
Teratogenesis is often difficult to prove. To detect a defect due to a specific agent, an
increase in a specific anomaly or group of anomalies over what would be expected by
chance must be documented.
What is an embryonic alteration in morphogenesis due to an intrinsically
abnormal developmental process such as may occur with a chromosome or
multifactorial disorder.
Malformation
What defects are the abnormal form, shape, or position of a body part arising
from extrinsic mechanical forces (e.g., clubfoot due to fetal restraint or lung
hypoplasia with congenital diaphragmatic hernia);
Deformation
What is caused by an external force that alters a previously normal tissue (e.g.,
teratogenic effects or amputation of a fetal part by an amniotic band).
Disruption
What is the cause of the majority of birth defects?
Sixty-five to seventy percent of birth defects are idiopathic with no known etiology
What are Wilson's Six Principles of Teratology
•Principle 1: Susceptibility to teratogenesis depends on the genotype of the conceptus
and the manner in which this interacts with environmental factors
•Principle 2: Susceptibility to teratogenic agents varies with the developmental stage at
the time of exposure.
•Principle 3: Teratogenic agents act in specific ways (mechanisms) on developing cells
QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS
VERIFIED LATEST UPDATE
What is a teratogen
A teratogen is any substance, organism, physical agent, or deficiency state present
during gestation that is capable of inducing abnormal postnatal structure or function
(biochemical, physiologic, or behavioral) by interfering with normal embryonic and fetal
development.
what are some substances that can act as teratogens?
-Infectious agents (such as toxoplasmosis, cytomegalovirus, syphilis), ionizing radiation,
hyperthermia, pesticides, metal (e.g., mercury and lead), organic solvents, excess or
deficient nutrients, effects of maternal chronic disorders (such as diabetes and
phenylketonuria), as well as over-the-counter, prescribed, and abused drugs. Some
herbal agents are also contraindicated in pregnancy, including those that have the
potential to act as abortifacients and/or uterine stimulants (black cohash, chamomile,
chasteberry, goldenseal, white horehound, licorice, mistletoe, nettle, pennyroyal, rue,
tansy, and yarrow).
-Heavy metals such as lead and mercury, organic solvents, alcohol, and ionizing
radiation are confirmed environmental teratogens, and exposure could contribute to
pregnancy loss
, Is it easy to identify a teratogen? Why or why not?
Teratogenesis is often difficult to prove. To detect a defect due to a specific agent, an
increase in a specific anomaly or group of anomalies over what would be expected by
chance must be documented.
What is an embryonic alteration in morphogenesis due to an intrinsically
abnormal developmental process such as may occur with a chromosome or
multifactorial disorder.
Malformation
What defects are the abnormal form, shape, or position of a body part arising
from extrinsic mechanical forces (e.g., clubfoot due to fetal restraint or lung
hypoplasia with congenital diaphragmatic hernia);
Deformation
What is caused by an external force that alters a previously normal tissue (e.g.,
teratogenic effects or amputation of a fetal part by an amniotic band).
Disruption
What is the cause of the majority of birth defects?
Sixty-five to seventy percent of birth defects are idiopathic with no known etiology
What are Wilson's Six Principles of Teratology
•Principle 1: Susceptibility to teratogenesis depends on the genotype of the conceptus
and the manner in which this interacts with environmental factors
•Principle 2: Susceptibility to teratogenic agents varies with the developmental stage at
the time of exposure.
•Principle 3: Teratogenic agents act in specific ways (mechanisms) on developing cells
