Developmental Biology Study Notes

Genetics Overviews

  • Discussion on the completion of genetics material with focus on upcoming content.

  • Chapters one and two will no longer be explicitly tested on future exams, as students have already been quizzed on those topics.

Introduction to New Material

  • Transition into new topics focusing on actual development.

  • Emphasis on storytelling as a teaching method.

Personal Anecdotes Connect to Developmental Stages

  • Introduction of "babies" to be discussed throughout the semester:

    • My nieces: Sydney and Devon, now late teenagers (turning 21 in May 2024).

    • Focus on early childhood, middle childhood, and adolescence experiences.

    • Denali: Turning 7 soon, discussion on temperament and physical disabilities, with a focus on Denali having a specific disability.

    • Sierra: Denali's little sister, also mentioned in discussions about childhood.

    • Twiblings: Henry (biological child) and Laurel (adopted from Henry's 16-year-old pregnant relative).

    • Discussion points include gender differences and rapid growth during the first year, illustrated with week-by-week growth slides for Henry.

    • Silas and Nia: Marco's children; connection to attachment topics and the zone of proximal development.

    • Experiences shared such as Silas's first nervous school day.

Family Backgrounds

  • Adolescence experiences shared relating to the speaker's sister and their family dynamics (no photos included).

  • Parents: Discussing the speaker’s mom as an only child due to family struggles with pregnancies (11 miscarriages and one stillborn).

    • Mom’s wedding at a botanical garden with a cost of $35.

Conception and Pregnancy Development

  • Introduction to pregnancy, noting there are differing opinions on when life begins:

    • Biologically, life begins at conception, but that does not equate to pregnancy.

  • Ovum Release:

    • Released approximately every 28 days (subject to individual variability).

  • Ovum Survival and Sperm Lifespan:

    • Ovum survives for about 1 day post-ovulation while sperm can survive up to 6 days in the fallopian tube.

    • Misconception regarding excessive frequency of intercourse for conception; having regular unprotected sex around ovulation is effective without exhaustion.

Timeline of Conception and Pregnancy

  • Germinal Period:

    • Spanning 0-2 weeks post-conception.

    • Overview of zygote formation and its journey to implantation in the uterine wall (10-14 days duration).

    • Pregnancy Testing and Miscarriages:

    • Miscarriages are common at this stage; usually occur before detection.

Key Stages of Pregnancy

  • Embryonic Period (Weeks 3-8):

    • Major prenatal changes; development of vital organs like heart, brain, sensory organs.

    • Cephalocaudal development’s prominence; head develops prior to limbs, creating characteristic formation.

  • Fetal Stage (after 8 weeks):

    • Focus on completing organ development and readiness for external life post-birth.

  • Neurosensory Development:

    • Second trimester is notable for increased activity and responsiveness; babies can recognize sounds and react to stimuli.

Viability and Premature Births

  • Fetal viability generally begins around 20-26 weeks gestation.

    • Historical anecdote about a baby born at 20 weeks; importance of medical practices associated with extreme premature births.

Teratogens and Their Impact on Development

  • Definition of Teratogens:

    • Environmental agents leading to fetal harm, including substances from outside the body and stress.

  • Implications of Timing on Teratogenic Exposure:

    • Critical periods affecting heart/lung development, external genitalia, etc.

    • Germinal vs. Embryonic: Different types of damage and outcomes depending on exposure timing.

  • Common Agents:

    • Drugs (prescription and illegal), environmental pollutants, stress, infectious diseases (e.g., Zika), radiation.

  • Discussions on the risks of specific substances, effects on fetal development, and recommendations for prenatal care and medication.

    • Notably, many recommendations include reaching out to healthcare professionals for guidance on medication and habits if pregnancy is desired.

Key Discussion Points

  • Current Knowledge Gaps in Teratogenic Risks:

    • Need for heightened awareness concerning timing and nature of risks, especially before pregnancy is confirmed. The tendency for women to take preventative health measures only once pregnancy is known can lead to preventable issues.

Feedback and Conclusion

  • Encouragement of continued engagement in understanding developmental phases and prenatal health.