Chapter 8: Physical Growth, Maturation, and Aging

KIN 4512

Genotype

46 chromosomes, deoxyribonucleic acid, genes make up 2% of human genome

Genetic mutations

changes in sections of DNA caused by random or environmental factors.

Crossing over

sections of DNA switch from one chromosome to another.

Random assortment

shuffling of the chromosomes that are in the sperm/egg.

Gene expression

genes are controlled vias regulator genes that can turn genes on and off throughout the lifespan.

Polygenic inheritance

traits controlled by more than one gene, applies to most traits and behaviors of interests to behavioral scientists

Recessive gene disorders

PKU, sickle-cell anemia, Tay-Sachs disease, and cystic fibrosis.

Dominant gene disorders

Huntington’s disease and neurofibromatosis

Polygenic inheritance disorders

heart disease, diabetes 1 and 2, asthma, psychiatric, and behavioral disorders

Trisomy 21

chromosomal/genetic disorder caused when abnormal cell division results in an extra full or partial copy of chromosome 21. Causes mold/moderate intelligence deficits, physical growth delays, unique facial characteristics, and motor delay.

Fetal nourishment

placenta allows transfer of oxygen, nutrients, and waste, it also prevents the mixing of blood of mother and baby. Fetal nourishment is an extrinsic factor with the most influence on fetal development.

Maternal diabetes extrinsic factors

can cause chronic hypoxia and intrauterine growth restrictions; causing lower IQ, elevated risk of abnormal glucose homeostasis and insulin resistance, and delays in psychomotor development.

Teratogen

any drug or chemical agent that causes abnormal prenatal development upon exposure, if delivered through nourishment system they will act as an malformation-producing agent

Epigenetic mechanisms

mediated by the environment, alter gene functioning, and creates stable changes in gene expression.

Prenatal development

process in which a baby develops from a single cell after conception into an embryo and later a fetus.

Embryonic growth

conception-8 weeks, cell differentiation occurs, limbs are formed at 4 weeks, body is semi-form becomes noticeable at 8 weeks.

Cell differentiation

process wherein cells become specialized, forming specific tissues and organs

Fetal development

9 weeks+, additional growth and cell differentiation of fetus occurs plus functional capacities, growth occurs via hypertrophy of hyperplasia.

Hypertrophy

increase in relative sizes of individual cells

Hyperplasia

an increase in the absolute number of cells.

Cephalocaudal

direction of growth: head/facial structures→ upper body—> lower body

Proximodistal

direction of growth: trunk→ nearest parts of limbs→ distal part of limbs

Plasticity

the capability to take on a new function

Sigmoid (s-shaped) curve

overall growth follows curve; curve has multiple phases of growth: lag phase→ exponential/log phase→ stationary phase

Weight

a sigmoid pattern growth, very susceptible to extrinsic factors.

Catch-up growth

faster than typical growth patterns which compensates for a transient period of growth inhibition, demonstrates extrinsic influences