Chapter 6: Bones and Skeletal Tissues - Simple Study Guide

Chapter 6: Bones and Skeletal Tissues – Simple Study Guide 1. Skeleton Overview • Axial skeleton: skull, spine, ribs, sternum • Appendicular skeleton: arms, legs, shoulders, hips • Skeleton starts as cartilage, then turns into bone (ossification) 2. Main Functions of Bones • Support and protect body and organs • Help with movement (act as levers for muscles) • Store minerals (calcium, phosphorus) • Make blood cells (hematopoiesis) • Store fat in yellow marrow • Release hormones for energy and blood sugar 3. Cartilage Types • Hyaline – most common (joints, ribs, nose) • Elastic – flexible (ear, epiglottis) • Fibrocartilage – strong (spine discs, knees) 4. Types of Bones • Long – femur, humerus • Short – wrist, ankle • Flat – skull, ribs, sternum • Irregular – vertebrae, hip 5. Bone Cells • Osteogenic – stem cells that make new bone cells • Osteoblasts – build bone • Osteocytes – maintain bone • Osteoclasts – break down bone 6. Bone Marrow • Red marrow – makes blood cells • Yellow marrow – stores fat • Found mostly in hip bone and sternum 7. Hormones & Bone Control • PTH (parathyroid): raises blood calcium by breaking down bone • Calcitonin (thyroid): lowers blood calcium by building bone 8. Ossification (Bone Formation) • Endochondral – replaces cartilage (most bones) • Intramembranous – forms flat bones (skull, clavicle) 9. Bone Growth • Bones grow in length at epiphyseal plate • Grow in width by adding layers outside • Growth hormones and sex hormones control growth 10. Bone Remodeling • Old bone replaced by new bone all life • Happens because of stress, hormones, or calcium levels 11. Bone Repair 1. Hematoma (blood clot) forms 2. Soft callus (cartilage) forms 3. Hard callus (spongy bone) forms 4. Bone remodeled to original shape 12. Bone Disorders • Osteoporosis – weak bones (common in older women) • Rickets – soft bones in kids (lack of vitamin D) • Paget’s disease – abnormal bone growth 13. Quick Review • Axial vs appendicular skeleton • 4 bone types and examples • Bone cells and what they do • Red vs yellow marrow • PTH vs calcitonin • Steps of fracture repair Tip: Focus on main functions, bone cells, and hormone effects. Know which bones belong to each skeleton and steps in bone repair.