Microscopic Structure of Compact Bone What are osteocytes

Microscopic Structure of Compact Bone • What are osteocytes? • Osteocytes and layers of intercellular material form concentric rings around a central canal, forming a cylindershaped unit called an osteon (Haversian system). • Each central canal contains blood vessels and nerve fibers surrounded by loose connective tissue.

Label Femur Diagram Handout • Review the following terms: – Distal – Proximal

Microscopic Structure

Bone types • 1. 2. 3. 4. Remember: Bones differ greatly in size and shape, but are similar in structure. Long Bones – work as levers; EX: bones of upper and lower limbs Short Bones – short and cubed shaped; found in wrist and ankles Flat Bones - broad surfaces for protection of organs and attachment of muscles; EX: ribs, cranial bones Irregular Bones – vertebrae and some bones in skull

Skeletal Organization • The skeleton is divided into two major parts: 1. Axial (? ? ? ) skeleton 2. Appendicular (? ? ? ) skeleton

Axial Skeleton • Consists of the bony and cartilage portions that support and protect the organs of the head, neck, and trunk.

Axial Skeleton parts: 1. Skull – made of the cranium and facial bones 2. Hyoid bone – found in the neck between the lower jaw and the larynx (this bone supports the tongue) 3. Vertebral column – vertebrae, sacrum, and coccyx 4. Thoracic cage – ribs (12 pair) and sternum

Appendicular Skeleton • Consists of bones of the upper and lower limbs and the bones that anchor the limbs to the axial skeleton.

Appendicular Parts: 1. Pectoral Girdle – scapula and clavicle 2. Upper Limbs – humerus, radius ulna, carpals, metacarpals, phalanges 3. Pelvic Girdle – pelvis 4. Lower Limbs – femur, tibia, fibula, patella, tarsals, metatarsals, phalanges

• Which portion, axial or appendicular, do you think would have the largest number of bones? • Table 7. 1, p. 137, shows the skeletal organization in a semi-outline format. • ***Important bone terminology: Table 7. 2, p. 137

Skeletal Diagram • Label together • Use 4 different colored highlighters to highlight by TYPE of bone (long, short, flat, irregular)