Bones and Skeletal Tissues Chapter 6 Bones and Skeletal Tissues

Section 1 Skeletal Cartilage

Skeletal Cartilages Skeletal cartilage Made of some variety of cartilage tissue which consists mostly of water. Hyaline cartilages: provide support with flexibility 1. articular cartilages: cover ends of most bones at movable joints 2. costal cartilages: connect ribs to sternum 3. respiratory cartilages: larynx (voicebox) reinforce airways 4. nasal cartilages: support external nose

Skeletal Cartilages Elastic cartilages: contain more stretchy elastic fibers so they are better able to stand up to repeated bending Found in only two skeletal locations: External ear Epiglottis (flap that bends to cover larynx when we swallow) Fibrocartilages: highly compressible and have great tinsile strength Intermediate between hyaline and elastic Padlike cartilage of knee and between vertebrae

Growth Of Cartilage Bone has hard matrix, cartilage has a flexible matrix that can accommodate mitosis Provide new skeletal growth Grows in two ways: Appositional growth: Growth from outside Iterstitial growth Growth from the inside Cartilage growth usually ends during adolescence when the skeleton stops growing

Classification of Bones There are 206 bones in the human skeleton (adult) Divided into two different groups Axial Forms the long axis of body; skull, vertebral column, rib cage Protecting, supporting, or carrying other body parts Appendicular Bones in upper or lower limbs and girdles (shoulder/hips) locomotion

Classification of Bones For the most part, bones are classified by their shape: Long Short Flat irregular

Classification of Bones Long bones Longer than they are wide All limb bones but patella and wrist/ankle bones Short bones Roughly cube shaped Wrist and ankle bones Sesmoid bones: type of short bone (shaped like seseme seed) form in a tendon - patella

Classification of Bones Flat bones Thin, flattened, usually a bit curved Sternum, scapula, ribs, and skull bones Irregular bones Complicated shapes that fit none of the other catagories Vertebrae and hip bones

Functions of Bones Support Protection Movement Provide framework that supports the body and cradles its soft organs Protection Fused bones of skull protect brain, vertebrae protect spinal cord, etc… Movement Use bones as levers to move the body and its parts (walk, grasp, breathe); design of joints determines the types of movement possible

Functions of Bones Mineral and growth factor storage Reservoir for minerals, most importantly calcium Mineralized bone matrix stores important growth factors such as insulin Bone cell formation Most blood cell formation occurs in the marrow cavities of certain bones