The Skeletal System: Functions and Funny Bone Facts

1. Chapter 6 The Skeletal System

2. Functions of Bone • _____________________________ • It provides a framework for the body and gives it shape. • _____________________________ • It supports and protects organs from injury. • _____________________________ • It provides a place for muscles, tendons, ligaments and tendons of the body to attach and make movement possible • ____________________________ • It stores minerals (Calcium) • ____________________________ • It provides a place for hematopoeisis

3. Funny Bone Facts • Bone is the 2nd hardest substance in the body, after ________ • Capable of ______-________ if aligned and kept still! • _________________ = mineralization or hardening of bone • Placement of calcium and phosphorus crystals into bone • Osteoblasts are actually trapped in their _____________ due to the bone that they have made • Remember, when they are done making bone, their name changes • Osteocytes communicate with each other via ____________

4. Bone Structure • Two main types of bone: • _________________________- Light and spongy inner layer of bone. • Consists of tiny spicules with bone marrow between them. • helps reduce the weight of bone and arranged to withstand the forces that bone is subjected to • _________________________- Heavy and dense outer layer of all bones • Composed of haversian systems (small units of bone tissue)

5. Haversian Systems • Concentric layers of bone arranged around a central ____________ _______

6. Blood Supply to Bone • Tiny vessels penetrate the periosteum. • _______________ __________- tiny channels in the bone matrix that vessels pass through. • Are at right angles to Haversian canals • _______________ __________- Where large vessels enter the bone. • Carry blood into and out of bone marrow. • Can be mistaken for fracture on radiographs.

7. NUTRIENT FORAMINA

8. Bone Structure • 3 types of bone cells: • ____________________- cells that secrete the matrix of bone and supply the minerals to harden it • ____________________- inactive cells that have been trapped in the matrix they have created • _____________________- cells that remodel bone by eating it away from places it is not needed. They also allow the body to utilize the calcium that was stored in bone

9. ______________________- fibrous membrane that covers the outside of bone (except at the joint) • ______________________- fibrous membrane that lines the hollow interior surface of bones. • _______________ - the shaft of long bones • _______________ - the ends of long bones

10. Bone Formation • Bone is formed in 2 ways: • __________________________ (cartilage bone formation) • grows into and replaces cartilage • __________________________ (membrane bone formation) • develops from fibrous tissue membranes • Bone formation and growth is stimulated by ___________ _________(GH) from the anterior pituitary gland in the brain.

11. Endochondral Bone Formation • Cartilage to bone formation. • cartilage template is replaced by bone • How most bones develop • Starts in the ____________ growth center • Cartilage rods in the ____________ (shaft) of long bones are gradually replaced by bone. • ______________ growth centers develop in ____________ (ends) of bones

13. Growth plates (epiphyseal plates) • At the time of birth, a plate of cartilage remains at each end of long bones • Located between ____________ and _____________ • Sites of creation of new bone that allows bone to lengthen as animal grows. • ________________ is created on epiphyseal side while __________ is created on diaphyseal side. • When bone reaches full length, all cartilage is replaced by bone and plates “close”. • Remodeling may take place but bone will not get any longer. • Young animals may have epiphyseal ___________ because this area is weaker than rest of bone.

15. Intramembranous Bone Formation • Occurs only in flat _________ bones • Bone forms in the fibrous tissue that covers the brain of the ___________. There is no cartilage intermediary.