5 - Growth and Development

What is Peak Height Velocity? What factors contribute to this peak growth in height>

Peak height velocity is the period where maximum rate of growth (height) occurs during adolescence.

• genetics

• Nutrition

• Physical activity

What are ossification centres

Region of bone development - A specific place in a developing bone where bone-making cells begin to replace soft tissue or cartilage with hard bones

• What are the stages of bone development

1. Cartilage cell increase in number (hyperplasia) and size (hypertrophy)

2. Tissue is calcified (hardens tissue)

3. Tissue is invaded by nutrients and osteoblasts

4. Osteoclasts remodel the internal structure, harder external cortex (outer layer), less dense internal region (hollow structure)

What are the key differences between. Primary and secondary ossification centres

PRIMARY OSSIFICATION CENTRES - BEFORE BIRTH

• within the shaft of long bones

• Before birth during fetal development

• Initiates the formation of bone by replacing the cartilage model

• Not directly involved in the growth place

SECONDARY OSSIFICATION CENTRES - AFTER BIRTH

• at the ends of long bones

• After birth during childhood/adolescence

• Responsible for growth, shaping of bone ends, contributes to bone lengthening

• Forms the epiphyseal plate (growth plate)

What are the two types of bone

Trabecular Bone -

• greater surface area

• Promotes bone marrow development

• Trabeculae form along lines of stress

Cortical Bon (compact) -

• closely packed bones

• Hard, dense

• Support the body, stores calcium

• Highly organised structure

What is Wolff’s law

States that a bone grows or remodels in response to the demands placed on it