16. Age Flashcards
What are the phases called associated with foetal growth/pubertal growth?
Foetal growth - hyperplasia (cell multiplication)
Pubertal growth - hypertrophy (cell expansion)
What are the 4 phases of growth and development - with years and key point?
Infancy (0-2yrs)
- skeletal growth greatest up to 4months.
Early childhood (3-8yrs)
- fine motor skills 3-5yrs
- body proportions refined 5-8yrs
Middle childhood (9-11yrs) - slow and steady physical development
Adolescence (12-18yrs)
- growth spurts= 2 years fast, 3 years slow
- testosterone and oestrogen influence anabolic effects
When does adolescence happen for girls vs boys?
Girls: 12-18yrs
Boys: 14-20 yrs
What causes a loss of coordination/injury in children?
Bones grow first and muscles/tendons become inflexible.
Longer limbs and lack of muscular structure.
At what age do girls have larger muscles than boys?
12-13yrs
Long bones ____ through ______ at ______ and increase in width through ________
Long bones length through addition of bone tissue at the epiphyseal plate and increase in width through appositional growth.
What age is ossification complete?
18-13 years
Describe appositional bone growth
- Osteoblasts lay down calcium and phosphate crystals around the shaft of the cartilage.
- Osteoclasts remove old bones that line the medullar cavity.
- Osteoblasts produce new bone tissue beneath the periosteum.
- Erosion of old bone along medullar cavity and deposition of new bone beneath the periosteum = increase diameter of the diaphysis/medullar cavity.
Describe longitudinal bone growth
- Cartilage is formed on epiphyseal side [top] of epiphyseal plate (growth plate)
- On diaphysial side [bottom] cartilage is ossified allowing the diaphysis to grow in length.
What does the growth hormone do?
- Elongation of limbs by osteoblasts and closure of epiphyseal plate
- Absorbs amino acids and protein
- Breakdown fat for energy
- Body fat levels decrease/increase among males/females
How does body composition change for teen females? %
Lean body mass falls from 80% to 74%
Body fat increases from 16% to 27%
What is testicular testosterone secretion associated with?
Increases in fat free mass
What are training-indued strength gains related to in children?
Neural mechanisms rather than hyperthropic factors
What happens to amount of red blood cells/haemoglobin concentration in pre and post puberty in males and females? %
RBCs: 47% boys and 42% girls
Haemoglobin: increases for boys, remains stable for women
What substrate do children rely on for exercise?
Fat (rather than glycogen as lower stores)