Chapter 11 Skeletal System What are the functions of the Skeletal System Supports the body Protects the soft body parts Produces blood cells Stores minerals calcium and phosphate and fat Allows for movement by attaching muscles What is the anatomy of a long bone Articular cartilage hyaline cartilage found on the ends of long bones Yellow bone marrow stores fat Red bone marrow makes blood cells found in spongy bone and flat bones Periosteum living outer covering of fibrous connective tissue Ligaments fibrous connective tissue that connects bones Diaphysis shaft of the bone made of compact bone and filled with yellow marrow Epiphysis ends of the bone made mostly of spongy bone Compact bone is composed of osteons with a central canal containing blood vessels Contains living bone cells called osteocytes in chambers called lacunae Spongy bone is made of plates with spaces filled with red bone marrow Important cells in bone growth remodeling and repair Osteoblasts bone forming cells Osteocytes mature bone cells that maintain bone structure derived from osteoblasts Osteoclasts bone absorbing cells Chondroytes cartilage forming cells The axial skeleton Skull made of cranium and facial bones The cranium Protects the brain Has some bones that contain the sinuses Is composed of 8 bones Hyoid bone Vertebral column vertebrae and intervertebral disks Rib cage ribs and sternum The 206 bones of the body Overall functions and components cranium stimuli rib cage vertebral column Types of vertebrae 33 vertebrae Cervical 7 Thoracic 12 Lumbar 5 Sacrum 5 fused Coccyx 4 fused into tailbone Intervertebral disks Fibrocartilage between vertebrae The rib cage Rib s Protect the heart and lungs Flattened bone originating from thoracic vertebrae 12 pairs 7 pairs true ribs start connecting at the Sternum 3 pairs false ribs connected to true ribs 2 pairs floating ribs floating in thoracic cavity Sternum Known as breastbone The appendicular skeleton Pectoral girdle Scapula and clavicle Upper limb Arm and hand bones Pelvic girdle Coxal bone Lower limb Leg and foot bones Fubula is fible skinnier Tibula is wider Types of joints where bones meet bones Fibrous usually immovable such as the sutures between cranial bones Cartilaginous tend to be slightly movable such as the intervertebral disks Synovial freely movable joints such as the ball and socket hip and shoulder joints and the hinge knee and elbow joints How do hormones affect bone growth Vitamin D is converted to a hormone that allows calcium absorption in the intestine to the blood to the bone and bone matrix is hardened and restored Growth hormone GH stimulates general bone growth and the epiphyseal plates Sex hormones increase growth during adolescence Osteoporosis Osteoporosis is a condition where bones are weakened due to a decreased bone mass brittleness Bone reabsorption exceeds absorption usually by age 40 Risk factors include women white or Asian thin family history early menopause smoking diet low in calcium excessive caffeine or alcohol consumption and a sedentary lifestyle Osteoporosis can lead to fractures and other complications It can be treated with drugs hormones and lifestyle change White people have less melanin which increases pigmentation black They are important for combat of ultraviolet radiation Melanin helps in absorption of Vitamin D
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