Physical Growth, Maturation, & Aging Flashcards
PRENATAL DEV stages
Embryonic Development (0-8 weeks)
Fetal Development (8 weeks-birth)
embryonic dev functions
Sex cells - ovum/spermatozoon
Fertilization - fusion of sex cells(increase in number of cells)/IMPLANTATION
Differentiation - cells change into specific tissues and organs
what are the 3 germ layers in embryonic stage
Ectoderm, Mesoderm, and Endoderm
fetal dev functions
Hyperplasia - increase in number of cells
Hypertrophy - increase in size of cell
Growth directionality - cephalocaudal/proximodistal
Most influential extrinsic factor to fetal development.
Fetal Nourishment & Exchange -
material blood surrounds to exchange:
- Oxygen/Carbon dioxide diffusion
- Food energy/Excretory byproducts
- Nutrients & Hormones
- Mother and fetus can compete for low supply resources, usually detrimental to fetus.
Ectoderm locations
skin, eyes, nerves
Mesoderm locations
bones, blood, muscles
Endoderm locations
lining of gut, lungs, liver
what are congenital defects?
Anomalies present at birth (detected or not), regardless of whether their causes are genetic or extrinsic.
- Genetic influences occur on our
chromosomes
- Chromosomes - wound up DNA
- Alleles - a gene type for a given trait.
- Phenotype - observable display of genetic
traits.
Genetic cause defects:
Dominant traits
- Inherit from one parent
- EX: Huntington’s Disease
Recessive traits
- Inherit from both parents
- EX: Cystic Fibrosis, Sickle cell
Sex-Linked
- Inherited on a sex-chromosome (X or Y)
Spontaneous mutations
- Occur over time to sex cells from extrinsic factors
Extrinsic cause defects
Virus/Infections
- Ex: Rubella (but vaccination prevents this)
- Nutrients
- Too high or too low
- Hormones
- Too high or too low
- Teratogens
- Any drug or chemical that causes
abnormal prenatal development upon
exposure
- Drugs with molecular weight of over 1000 amu do not cross placenta
- Ex: Fetal Alcohol Spectrum Disorder
- Physical Pressure
- Internal or external pressure on fetus
- Temperature
- Extreme too high (fever) or too low (hypothermia)
- Electromagnetic radiation (EMR)
- X-Rays, gamma rays
- Low Environmental Oxygen - Elevation, atmospheric pressure
- Environmental Pollutants/Smoking - Acts like teratogen
Things that can be done to help with healthy fetal development:
Avoid teratogens.
● Supplement with folic acid (prevents neural tube defects).
● Follow a healthy diet:
○ Avoid: methylmercury in fish (limit seafood), raw deli meats, & unpasteurized dairy
○ Limit caffeine to under 200mg/day
○ Maintain healthy weight (depends on starting weight how
much you can expect to gain)
○ B12 and iron (check levels)
● Prevent infections (check that all your vaccinations are up to date)
Postnatal dev deals with:
Overall Growth
○ Factors Affecting
Growth
● Adulthood and Aging
sex factors affecting growth:
childhood sex differences are minimal for height and weight
- Tendency to stay in “percentile” throughout childhood
- Physiological maturation
- Chronological age may not be indicative of physiological developmental age
- Menarche
- First menstrual cycle
- Follows PHV by a year
- Starting younger than historically
recorded (~12 years old)
Peak height velocity (PHV)
- Females mature sooner and faster than boys
- Males later but longer
- Average onset of puberty girls is 9, boys 11
Weight
- Although follows same
sigmoid as height, more susceptible to extrinsic factors
- Ex: Muscle, diet, exercise, sedentary time
- “Grow up, and fill out” is true
- Peak weight velocity follows PHV
- Boys by 2.5-5 months
- Girls by 3.5-10 months
Adulthood and Aging height and weight:
Height
- Generally done in 20’s
- Can increase slightly into 40’s
- Decreases in older age as compression of
bones occurs
Weight
- Generally excess fat storage starts to occur in
early 20’s
- Largely due to lifestyle changes, genetics
can play role
- Older adults sometimes lose weight
- Inactivity and loss of muscle tissue, loss of appetite
