Growth And Development Flashcards
What type of fracture is a young child most likely to attain?
Greenstick
What is the term used for teenagers taller than their parents?
Secular trend
What does allometric mean?
changes shape in response to changes in size
What is the Square / Cube Law?
Surface area (SA) increases as the square of the height (Ht): nSA*Ht^2
Mass (M) or Volume(V) increases as the cube of height(Ht): M or V^3*Ht^3
As a shape grows in size, volume(V) grows faster than SA. describes SA:V ratio
Allometric differences in bones between adults and children?
adult bones are proportionately muchlarger than a child’s; they carry proportionately higher weight
If a person was double their size but kept the same shape, what would their strength be like?
Double the height BUT keep same shape = 1 x muscle power to move 2 x the mass! Instead of having the same relative agility, the double-sized human will only have half
What is strength a function of?
area: strength of a muscle/bone is to its cross-sectional area (CSA)
Ratio of height, strength and body mass in allometric scaling?
Ratio of height (H)=132/120 = 1.10 10% taller
Ratio of strength ≈ H2: (1.10)^2 21% stronger
Ratio of body mass ≈ H3: (1.10)^3 33% heavier
What is thermoregulation?
A process that allows your body to maintain its core internal temperature
or
return your body to homeostasis, i.e., maintain a state of equilibrium
What can effect thermoregulation?
Growth can greatly affect thermoregulation –disruption to homeostasis can affect your body’s ability to function
In regards to thermoregulation, what factors are dependent on mass?
Metabolic heat (food, muscles, endocrine system) and environmental heat
In regards to thermoregulation, what factors are dependent on body surface?
Radiation
Conduction
Convection
Evaporation
How does skin lose heat?
It radiates small amounts of radiant energy, passes heat to cooler objects, evaporation, and cooler air currents remove the heat from the skin
What is heat production dependent on?
Body mass
What is heat dissipation dependent on?
Surface area
Why do children overheat less?
Mass increases as the cube of height
Surface area increases as the square of height
A child will have more SA/mass
What temperature range is hypothermia?
Above 39 degrees
What temperature range is hypothermia?
below 35 degrees
What is the height differential between a 15 year old boy today and a 15 year old boy 130 years ago?
19cm
what is the height differential between an adult man today and an adult man 100 years ago is approximately 4 cm
4cm
How much had Menarche decreased between 1880-1960?
From 1880 to 1960, there has been a decrease in the age of menarche by about 0.3 years per decade (↓ 2.4 years over 80 years). (all countries)
Reasons for trends toward early maturation?
- Better nutrition
- Nutritional status→weight/fatness→timingof sexual development (critical weight hypothesis)
- Improved environmental circumstances (water, housing, etc.)
- Reduction in the incidence of childhood disease
- Second-hand hormones (meat, milk)
- Environmental chemicals (bisposphenolA, PCB etc.)
- Gut microbiota: composition and activity of gut bacteria can vary according to life events: lean vs. obese individuals have different gut profiles
Change in size is due to:
Hypertrophy
•Hyperplasia
•Accretion
Four elements of growth?
Differentiation
Translocation
Maturation
Adaption
