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Human Reproduction, Development and Ageing - Week 10 Lecture Notes (2)

Topic = Human Growth, Adolescence and Maturity

Plan Overview for Developmental Origins of Health and Disease (DOHaD)

  • Topics to be covered:

    • Development of newborns

    • Understanding adolescence

    • Growth & puberty.

Human Growth Definition

  • Growth: Biological process focusing on the physical changes in an individual (height, weight, organ size), notably rapid during childhood & adolescence, slowing at maturity. Influences from environmental and genetic factors exist.

  • Development: Continual process of cognitive, emotional, social, and moral progression affecting thoughts, behaviors, and interactions throughout life.

Research Context for Adolescence

  • Community Role: Enhancing youth understanding and wellbeing globally through high-quality research on biological, psychological, and sociocultural developmental aspects.

  • Meetings: Highlighting diversity and inclusion in discussions; aiming to change traditional paradigms.

Reproductive Developmental Plasticity – Key Findings

  • Menarche: Earlier onset linked to higher mortality rates and risks (unintended pregnancies, STDs).

  • Young Motherhood: Indicators of poorer outcomes in pregnancy & infancy.

  • Sub-optimal Fetal Growth: Related growth and health issues can lead to health outcomes in adulthood.

Factors Influencing Age at Menarche

  • Influencing Factors:

    • Socioeconomic Status

    • Genetics

    • Nutrition

    • Exercise

  • Potential Effects:

    • Increased risks for developing breast, ovarian, and endometrial cancers

    • Mental health effects and adult diseases.

The Barker Hypothesis (DOHaD)

  • Key Concepts: Birth weight directly ties to lifelong health outcomes. Lower birth weights (e.g., under 2,268 grams) associate with heightened risk for conditions like coronary heart disease.

  • Evidence: Studies tracking health from birth weight data indicating long-term implications on heart disease and other health conditions.

Newborn Development - Key Processes

  • APGAR Test: Evaluates newborns based on Appearance, Pulse, Grimace, Activity, and Respiration at birth.

    • Each parameter scored from 0-2, with interpretation for required interventions based on scores:

    • Scores:

    • >7 Normal

    • 4-6 may need assistance

    • <4 critical intervention required.

  • Reflexes:

    • Rooting, Sucking & Swallowing, Grasping, Moro reflex, Walking & Stepping reflex, all indicating newborn's neurological health.

Assessment through Brazelton Neonatal Assessment

  • Focuses on the neonatal capabilities, scoring various aspects of development within the first weeks after birth.

Growth Trajectories in Puberty

  • Growth Patterns: Continued growth for 15-20 years post-birth with observational criteria including height, weight, organ weights, etc.

  • Percentiles: Charts depict child growth relative to age to determine appropriate growth benchmarks (e.g., below 3rd or above 97th percentile warrants further investigation).

Hormonal Control during Puberty

  • GnRH Mechanism: Hypothalamus controls the release of gonadotrophins and is less sensitive to feedback mechanisms as puberty onset reaches.

    • Influences steroid levels necessary for developing male and female characteristics (FSH & LH influence).

Age and Developmental Influences

  • Global Trends: Shifts in menarche timings highlighted by nutrition and health standards shape developmental expectations. E.g., assessments across decades show trends vary by region and societal conditions.

Significance of Healthy Childhoods

  • Emphasis on how improved health conditions mark transitions from puberty into adulthood for females, impacting reproductive health and self-image in future generations.

Concluding Notes

  • Understanding the connections between childhood conditions, social factors, and developmental timings is crucial for shaping health policies and educational programs to enhance the future trajectory of youth development.

  • Continuous review and adaptive learning in understanding sex differentiation and the biological basis of puberty are essential to comprehending socio-health dynamics.