Chapter 8 Physical Growth, Maturation, and Aging

Genetic factors

genetics that can be passed on from parents and can impact development

Extrinsic factors

Primarily environmental factors that contribute to aging and the appearance of aging.

Universality

Patterns that apply to all humans.

Specificity

Individual variations in growth patterns.

Growth

Physical size increase.

Maturation

Functional and structural changes.

Embryonic period

Stage (conception to 8 weeks) when cell differentiation occurs, limbs form, and the human shape becomes visible.

Fetal Period

8 weeks to birth- Continued growth by hyperplasia (cell number) and hypertrophy (cell size)

- Cephalocaudal (head to toe) and proximodistal (near to far)- Plasticity (capability of taking on a new function)

- Cephalocaudal (head to toe) and proximodistal (near to far)- Plasticity (capability of taking on a new function)

Plasticity in fetal development

The ability of cells to adapt and take on new functions if needed.

Differentiation

process in which cells become specialized in structure and function, creating specific tissues and organs

Fetal nourishment

Oxygen and nutrients diffuse between fetal and maternal blood via the placenta.

Teratogens

Harmful substances that can cause malformations in fetal development.

Alcohol

Drugs

Cigarettes

Lead Mercury

Postnatal growth pattern

Growth follows a sigmoid (S-shaped) pattern with periods of rapid and steady growth.

Hyperplasia

increase in number of cells

hypertrophy

increase in cell size

Peak height velocity for girls

Occurs at 11.5-12 years, growth ends around 16 years.

Peak height velocity for boys

Occurs at 13.5-14 years, growth ends around 18 years.

Factors influencing weight growth

Diet, exercise, and genetic predisposition.

Body proportions during growth

Infants have a head-heavy, short-legged body; proportions change to adult form during development.

Secondary sex characteristics

Traits that appear during puberty, such as facial hair in boys and breast development in girls.

Aging and height

Height remains stable but may decrease due to cartilage compression and osteoporosis.

Weight gain in adults in their 20s

Due to diet, decreased activity, and loss of muscle mass.

Extrinsic factors in postnatal growth

Become more influential over time, especially during infancy and adolescence.

Catch-up growth

The body's ability to recover growth after a period of deprivation.

Role of maturation in athletic performance

Early maturers may have an initial advantage in sports, but long-term performance depends on various factors.

Causes of abnormal prenatal development

Genetic mutations, inherited disorders, and extrinsic factors like teratogens.

Relationship between height and weight growth

Weight gain typically follows height growth by a few months.

Structural constraint in aging individuals

Changes in muscle mass, joint flexibility, and bone density impact movement efficiency.