Growth

Identify 3 types of bone cells

3 types of bone cells Osteocytes (osteons) – mature bone cells, in both spongy and compact bone Osteoclasts- multinucleated & dissolve bone matrix Osteoblasts- build new cells

Osteons Structures Functions Location Parallel to long axis of bone Therefore, limb does not bend Stress from one direction

Composition of bones Compact Spongy Epiphyseal line/plate

What is the main difference between spongy and compact bone? Why is a fracture more likely from the side of a bone? What does the presence of an epiphyseal line mean?

Bones If collagen increases in a bone, how is the strength of the bone affected? What is the anatomical and thus physiological difference between the diaphysis and epiphysis ? If osteoclast activity is higher than osteoblast activity what happens to a bone?

Calcification / ossification

Calcification vs. Ossification Calcification Buildup of Ca Occurs during ossification Can also occur in joints or other ares Ossificiation Intramembranous – bone develops directly Endochondral – bone replaces catilage Epiphyseal cartilage - at ends of epiphysis reduces as growth slows

What affects the growth of bones?

Why do teens grow suddenly? What happens at puberty? Is exercise important to bone development? How?

Primary/Secondary growth Elongation –diaphysis growth Laterally- the periosteum is increasing in osteoblasts, towards the inside, ________ are __________ and marrow cavity is increasing

When does one stop osteoblasting? Skull Toes Long bones Pelvis

What is needed for bone growth? Vitamins and minerals Sex hormones Fractures – will they stop growth? Stress applied to bones- good or bad? Why?

Vitamins A C D

Minerals Ca P

Age Normal loss of bone due to aging= osteopeniaj Hormone levels change Reduction in osteoblast activity Bones become ----? Who is affected more? Men/women Is this equally affecting the entire body or are some areas more affected earlier? What helps to reduce this process? Disorders/ diseases

What type of tissue is replaced by bone during intramembranous ossification? How would an X-ray of a femur tell if a person had stopped growing? Why should a pregnant woman take vitamin and mineral supplements?