The document discusses the process of ossification where cartilage is changed to bone during human development. It explains that ossification is impacted by three key cells: osteoblasts, which build bone; osteocytes, which are trapped osteoblasts that give bone its star-shaped appearance; and osteoclasts, which break down old or damaged bone. The document also outlines factors like nutrition, vitamins, hormones, and growth that influence bone growth and remodeling throughout life.

1. Growth of Bone Lloyd Dean Skeletal System

2. Ossification Humans have 206 bones New born babies have more than 300! In the embryo (our state before birth) most of the skeleton is made up of cartilage Cartilage is a firm, but elastic material

3. Ossification As the embryo grows, cartilage is changed to bone The development of bone from cartilage is termed “ossification” Ossification is impacted by 3 cells “ Osteo” is Greek for “bone” Osteoblasts Osteocytes Osteoclasts

4. Ossification Completed during three stages: Production of an extracellular matrix Osteoblasts produce collagen (Tough elastic) Calcium is utilised Mineralisation of matrix to form bone Osteoblasts fill spaces in bone with matrix, and then become trapped There are then known as Osteocytes and have a star shape appearance Bone remodelling Osteoclasts break down bone and Osteoblasts rebuild them Enables skeleton to repaid, adapt and build strong bones

5. Osteoblasts and Osteoclasts

6. Bone Remodelling

7. Osteoblasts, Osteoclasts and Osteoporosis

8. Bone growth cannot occur without sufficient dietary intake Calcium required for bones Vitamins C (Orange ), A (Milk), K (Wholegrain), and B 12 (Red meat ) are all necessary for bone growth Nutritional Impact On Bone

9. Growth hormone stimulates bone growth Thyroxine (Thyroid gland) increases the rate of osteoblast activity At puberty, sex hormones (estrogens in females and androgens in males) cause osteoblasts to produce bone faster than the epiphyseal cartilage can divide. Commonly know as “growth spurt” as well as the closure of the epiphyseal plate. Estrogens cause faster closure of the epiphyseal growth plate than androgens - Girls grow faster than boys! Hormones Impacting Bone Growth