Embryonic Period/Stage
- Week 3-8
- Possible to distinguish between cephalic and caudal regions
- Limbs have fully developed
- Eyes and ears are visible
Fetal Period/Stage
- Weeks 8-9 to birth
- Major growth in size
- Organ systems and height
- Non-linear growth
SRY Gene
Creates a cascade of 30 different genes that lead to the formation of testes, which produce testosterone.
Just because someone has a copy of the SRY gene doesn’t mean that…
- The SRY gene is functioning
- Testes have formed
- Their body produces testosterone
- The cells and tissues in their body respond to testosterone
Define XO
Turner Syndrome
Define XXY
Klinefelter Syndrome
Congenital Adrenal Hyperplasia
XX individuals have an overproduction of testosterone, leading to masculinization of female traits.
5-alpha-reductase Deficiency
Body cannot fully convert testosterone to DHT, causes ambiguous genitalia at birth.
Androgen Insensitivty Syndrome
Cells and tissues lack or have very few androgen receptors.
Infancy
0-2 years
Childhood and Juvenile
Childhood: 2-puberty
Juvenile: 7-puberty (no longer dependant on mother)
Adolesence
Puberty
Adulthood
Completion of growth
Thrifty Genotype
Traits for energy efficiency selected for due to historical food scarcity (natural selection) become maladaptive when exposed to modern Western diet.
Thrifty Phenotype
Malnutrition in utero causes DNA to be read differently during the lifespan. Using current conditions to predict future ones.
Thrifty Phenotype: Gestation Periods and Exposure Effects
Early Gestation: CVD, general poor health
Mid: Kidney disease associated with diabetes, lung disease
Late: Insulin resistance (diabetes)
Mechanistic Theories of Senesence
Hayflick Limit: a cummulative effect of a natural process, cells flatten and enlarge, become resistant to apoptosis, and increase in membrane rigidity
Telomere Attrition: shortening
Protein damage: Alzheimer’s, cross-linkage and denaturation of proteins
Evolutionary Theories of Senescense
Mutation Accumulation: aging is a by-product of natural selection, natural selection acts on early life success
Antagonistic Pleiotropy: effect of genes change over time, early life fitness for later life harm
System-Specific Theory: menopause could serve as a survival tool (“The Grandma Theory”)
Arterioscelrosis
Wall thickening
Artheroscelrosis
Plaque build-up
