Chapter 3: Physical Development Flashcards
What are growth norms?
expectations for typical gains and variations in height and weight for children based on chronological age and (usually) ethnic background
What do growth norms tell us?
- tells us if the child’s growth is normal and on-track with their peers
- tells us if they’re healthy in comparison to kids their age
Describe growth in infancy.
- most rapid growth of lifespan aside from embryonic period
- lose weight when born, quickly regain it, then go through growth spurts
- head is 25% of the length of the body
Describe growth in early and middle childhood.
- growth slows down considerably
- individuals body portions are much more like that of an adult
- as they’re growing, their proportions grow into the size of their head
How do genetics influence physical development in infancy and childhood?
by stipulating the amount of hormones that are released
How do hormones influence physical development in infancy and childhood?
influence cells, and are the way in which genetic instructions are transformed into physical development
How does the environment influence physical development in infancy and childhood?
good nutrition, health care, and clean water = influences better growth
What is puberty?
biological transition to adulthood in which adolescents mature physically and become capable of reproduction
When is puberty complete?
puberty is not complete until reproductive organs are all functional
What is the primary influence of physical development?
puberty
What is puberty regulated by?
regulated by hormones that are part of Hypothalamus-Pituitary-Gonadal Axis (HPG) → causes individuals to go through puberty
When does puberty start?
can start at 8 or 9 years old
girls typically start earlier than boys
How long does puberty take?
whole process takes about 4 years to complete
What is an adolescent growth spurt?
rapid gain in height and weight, can be painful and challenging
When does an adolescent growth spurt occur?
around age 10 (girls) and 12 (boys), and takes around 2 years
What changes do we see in an adolescent growth spurt?
- begin to see sex differences in body shape
- girls increase their fat to body ratio
- boys see an increase in muscle mass
What are secondary sex characteristics?
physical traits that indicate sexual maturation but are not directly related to fertility
ie. breast development, voice deepening, acne, and the growth of body hair
What are primary sex characteristics?
bodily changes directly related to fertility
What are primary sex characteristics in females?
menarche (first menstruation)
suggests that uterus and ovaries have grown and are now functional (ie. releasing an egg)
What are primary sex characteristics in males?
spermarche (first ejaculation)
suggests that testes, penis, and scrotum have grown and are now functional (ie. making and releasing sperm)
What is the biological influence on pubertal timing?
genetics: age at which mothers and fathers go through puberty will predict the onset of puberty in their children
What are the 3 contextual influences on pubertal timing?
- nutrition
- stress
- socio-economic status (SES)
How does nutrition affect pubertal timing in females?
ovulation and menstruation is triggered by specific level of protein called leptin found in fat
- as that protein increases, it increases the production and secretion of hormones which will then trigger the onset of puberty and the release of an egg
- fat leads to menarche