Physical Growth, Maturation and Aging

Question 1

What constraints effect growth and aging?

Answer 1

Genetic and extrinsic factors combine to influence growth and aging
We observe two patterns (universality and variety)

Question 2

What is prenatal development?

Answer 2

Early development is controlled by genes
-Normal development
-Inherited abnormal development
Embryo is sensitive to extrinsic factors (positive and negative)

Question 3

What is embryonic development?

Answer 3

Conception to 8 weeks
Differentiation of cell form specific tissues
Limbs form at 4 weeks
Human form noticeable at 8 weeks

Question 4

What is fetal development?

Answer 4

8 weeks- birth
Growth is by hyperplasia and hypertrophy
They grow cephalocaudal (head to toe) and proximodistal (near to far)
Plasticity (capability to take on new function)

Question 5

How does fetus get nourishment?

Answer 5

Oxygen and nutrients diffuse between fetal and maternal blood
Poor maternal health can affect fetus
Placenta acts as babies digestive and pulmonary system

Question 6

What causes abnormal prenatal development?

Answer 6

Genetic or extrinsic
Congenital defects can derive from genetic or extrinsic source
Congenital: present from birth

Question 7

What are the top five genetic birth defects?

Answer 7

1) heart defects
2) neural tube defects (spinal bifida)
3) blood disorders
4) down syndrome
5) G6PD (glucose 6 phospahte dehydrogenase) ( enzyme deficiency causes anemia)

Question 8

What are genetic causes of abnormal development?

Answer 8

Result from mutation of genes

effect on growth and maturation are variable

Question 9

What are extrinsic causes of abnormal development?

Answer 9

Teratogens: any drug, chemical, or virus that causes abnormal development
Delivered through the nourishment system
Mal-formation-producing agents
Can result from too much or too little of something
Placenta screens from some substances but not all

Question 10

What extrinsic factors cause abnormal development?

Answer 10

Harmful environmental factors –> pressure, temperature, x and gamma rays, oxygen deficient atmosphere, pollutants
Tissue undergoing rapid development at time of exposure are most vulnerable

Question 11

What are the top ten teratogens?

Answer 11

1) Alcohol
2) Nicotine
3) Cocaine
4) Viruses
5) Syphilis Bacteria
6) Toxoplasma
7) Category x Drugs ( anti-cancer, anti-seizure)
8) Category D drugs (antibiotics)
9) Chemicals
10) Ionizing radiation

Question 12

What is postnatal development?

Answer 12

Overall growth follows sigmoid pattern
Timing of spurts and steady periods can vary among individuals
Timing differs between sexes

Question 13

What is the pattern of height in girls?

Answer 13

Follows sigmoid pattern
Peak height velocity occurs at 11.5 - 12 yrs
Growth in height tapers off around 14 and end around 16

Question 14

What is the pattern of height in boys?

Answer 14

Peak velocity occurs around 13.5 - 15 yrs.
Growth height tapers off around 17 and end at 18
Longer growth period contributes to height difference

Question 15

What are individual variations of height?

Answer 15

Average ages fro peak height velocity and tapering of growth are based on groups
Individuals can differ from averages

Question 16

What is the pattern for weight in girls?

Answer 16

Sigmoid pattern
susceptible to extrinsic factors (diet/exercise)
Follows peak height
3.5-10.5 months after

Question 17

What is the pattern for weight in boys?

Answer 17

Sigmoid pattern
Susceptible to extrinsic factors
Follows peak height
2.5-5 months after

Question 18

What is the assessment of extent and rate of postnatal growth?

Answer 18

Distance curves show extent of growth
Velocity curves show rate of growth
Peaks on velocity curves show ages at which rate of growth changes from faster to slower

Question 19

What is relative growth?

Answer 19

Body as a whole follow sigmoid pattern; specific parts tissues and organs have different rates
Body proportions change from head heavy, short legged form at birth to adult proportions
In adolescence, boys increase in shoulder breadth

Question 20

What was there a rapid rise in between 1980 and 2004?

Answer 20

Obesity doubled from 15% to 30%

Overweight children tripled from 5.5% to 17%

Question 21

What are some trend of OW and OB rates in US adults?

Answer 21

1) 2005-2006 first time prevalence of OB (35.1%) greater than OW (32.2%)
2) OB% has doubled from 1960 but OW% has stayed stable
3) OW% is stable because the number of people from normal to OW equal number of people from OW to OB
4) Appearance of extreme OB

Question 22

What are some trends of OW and OB rates in Canada?

Answer 22

1) OW% IS STABLE BECAUSE # OF PEOPLE CHANGING FROM NORMAL TO OW = SAME # OF PEOPLE FROM OW TO OB
2) Greatest increase over time is Class II and III obesity (425%)
3) Trends appear to be continually movement up through the classes from normal weight to class II and II

Question 23

What are some trend in female OB rates?

Answer 23

1) Canada lower than the US in all ages
2) Pattern of OB is the same as you progress from 18-74
3) Drop in PB rates in 65-74yrs because people are dying

Question 24

What does the Canadian Physical Activity Index say?

Answer 24

1995-2005

1) increase in # of active Canadians
2) stable # of moderately active Canadians
3) Reduction in the number of inactive Canadians

Question 25

What are points about the level of physical activity by age?

Answer 25

1) moderate active category similar for all ages of Canadians
2) Increase age = steady decrease in activity
3) Increase age = steady increase in inactivity

Question 26

What are patterns of OB rate of genders and races?

Answer 26

1) men of different ethnic background have little difference in OB rates
2) African -American and Hispanic women have higher prevalence

Question 27

What are patterns of OB rate by education?

Answer 27

1) The higher the education the lower the lower the BMI

2) all levels of education increase at the same rate

Question 28

What are the patterns of OB rates by income?

Answer 28

1) lower socio-economic = increase BMI
2) Least expensive food = increase level of sugar and fat
3) Most calories for least money = high in sugar
4) interaction of biology and economics

Question 29

What is physiological maturation of the body?

Answer 29

Tissue of the body can advance without necessarily increasing in size
As children grow, they grow in size adn mature
Maturation rates can vary
Difficult to infer maturity from size and age alone

Question 30

How are chronicle age, growth in size and physiological maturation related?

Answer 30

As children and youth become older, they grow in size and mature
But they proceed with their own timing.
Two children at the same age can be dramatically different in maturation status

Question 31

What are secondary sex characteristics?

Answer 31

Appear as a function of maturation

They appear at younger ages in early maturers

Question 32

What are extrinsic influences on postnatal growth?

Answer 32

Individuals are especially sensitive during periods of rapid growth
Catch up growth demonstrates extrinsic influences

Question 33

Patterns of height and weight in adulthood and aging

Answer 33

Height is stable but may decrease in older adulthood
-compression of cartilage pads
-osteoporosis
Average adult starts gaining weight in the 20s
-diet and exercise
-loss of muscle mass