UTPA STEM/CBI Courses/Comparative Embryology/Birth Defects and Their Causes

Course Title: Comparative Embryology, Biol 3407

Lecture Topic: Teratogens; agents that cause birth defects

Instructor: Dr. Tim Brush

Institution: University of Texas-Pan American

Backwards Design

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Course Objectives

• Primary Objectives- By the next class period students will be able to:
  • Explain the effects of different teratogenic agents
  • Explain the concept of sensitive periods
  • Explain the mode of action of selected teratogens

• Sub Objectives- The objectives will require that students be able to:
  • Remember basic developmental stages
  • Understand the concept of induction

• Difficulties- Students may have difficulty:
  • Understanding why particular systems or organs are affected by certain teratogens
  • Understanding the concept of sensitive period

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
  • Understanding causes of birth defects
  • Educating in order to affect preventable birth defects

Model of Knowledge

• Concept Map
  • Basic stages of development and what is happening
  • Factors causing problems with development
  • Miscarriage vs. birth defects
  • Genetic vs. “environmental” (teratogenic) causes
  • Different classes of teratogens—organisms, chemicals, physical factors, other

• Content Priorities
  • Enduring Understanding
    • Causes of birth defects
    • Teratogenic effects
    • Sensitive periods
  • Important to Do and Know
    • Teratogenic modes of action (examples)
    • Reasons for sensitivity
  • Worth Being Familiar with
    • Characteristics of teratogen
    • Commercial uses of teratogens (if any)

Assessment of Learning

• Formative Assessment
  • In Class (groups)
    • Discussion of modes of actions and sensitive period
    • Report on teratogen researched

• • Homework (individual)
    • Quiz on basic knowledge of teratogens and effects
    • Research on a particular teratogen chosen

• Summative Assessment
  • Quiz on teratogens
  • Test (questions on final exam)

Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

• List the major causes of birth defects
• List the types of teratogens and their effects
• Understand the concept of sensitive period

The objectives will require that students be able to:

• Integrate the study of teratogens with earlier material on normal embryonic development
• Connect the concepts and inducers and teratogens
• Remember the basic embryological processes and stages

THE CHALLENGE

You are a medical doctor who is serving as the public health officer for a metropolitan area on the US/Mexico border. In the last two years, there has been a cluster of neural tube defects in newborns in area hospitals. You are responsible for determining the likely causes of this cluster and suggest the best preventative measures to prevent future occurrences.

GENERATE IDEAS

Individually and in groups, discuss possible causes of neural tube defects (NTD's) and how to study this (what kinds of data are needed)

MULTIPLE PERSPECTIVES

Listen to interviews with public health officials, parents of children who were born with varying neural tube defects, epidemiologists, etc.

RESEARCH & REVISE

• What kind of information is required and how would you gather it?

(Field work on environmental causes and via questionnaires of parents before and after/aspects of study design)

• Causes of birth defects in general---neural tube defects in particular—Valley situation.
• Genetic susceptibility among different ethnic groups/geographic locations: how to get this information.
• Role of diabetes/obesity and related metabolic conditions in preventing normal neural tube closure
• Effect of dietary folic acid on neural tube closure—effects of sources of folic acid and information lacks
• Possible environmental agents that may interfere with neural tube closure and their sources: general water and air, diet, workplace environment
• Interactions between above factors
• Why would education and place of birth/living be important?

TEST YOUR METTLE

Pre and post quiz on general concept of induction, embryonic development, and factors causing/preventing neural tube defects

GO PUBLIC

10-15 minute presentation on problem discussion and study proposal to deal with neural tube defect cluster. Will include field and survey-based research and presentation at level appropriate to interested public.

Pre-Lesson Quiz

1. What do the terms induction and competence mean?
2. How does eye development provide examples of induction and competence?
3. How do genes affect embryonic development?
4. What are the main periods of embryonic development in humans?
5. What are some examples of some birth defects?
6. What are some causes of birth defects?
7. What are spina bifida and anencephaly?
8. Are you aware of any clusters of birth defects in the Valley?

Test Your Mettle Quiz

1. How do inducers affect gene activity?
2. What is the difference between a promoter and an enhancer and how are they regulated?
3. What is the interaction between transcription factors and paracrine factors?
4. How do paracrine signaling and juxtracine signaling affect gene activity?
5. What are some teratogens that affect nervous system development and what problems do they cause?
6. Focusing on the neural tube defects (NTD's), what are the known causes of spina bifida and anencephaly?
7. What were the most likely causes for the cluster of NTD's in the Brownsville area in the 1990s?
8. What are the best ways (strategies) to prevent or reduce the occurrence of NTD's?
9. What are some barriers to implementing those strategies?
10. What are some important knowledge gaps in prevention and/or treatment of NTD's?