Chapter 6 Skeletal System

Functions Support Protect Movement and anchorage Mineral storage Ligaments are fibrous bands that connect bones to bones and cartilage and serve as support for muscles Tendons are fibrous cords that connect muscles to bone Mineral storage Hemopoiesis

Structure and Formation of Bone Osteocytes Mature bone cell Organic material (flexibility) Collagen Jellylike material Inorganic material (hardness and durability)

Bone Formation Embryonic skeleton initially consists of collagenous protein fibers secreted by osteoblasts 8th week of embryonic development, ossification begins Mineral matter starts to replace previously formed cartilage, creating bone

Long Bones Shaft or diaphysis Each end is the epiphysis Covered by articular cartilage In center is the medullary canal Yellow bone marrow Endosteum (lining of the marrow canal) Red marrow Ends of long bones Manufacture some red blood cells and some white blood cells Periosteum Covering on outside of the bone

Growth Grow in length Ossify from center outward Osteoblasts Osteoclasts Growth stops when all the epiphyseal cartilage is ossified Females grow until about 18 years of age Males grow until about 20-21 years of age

Types of Bones Long Flat Short Irregular

Axial Skeleton Skull Ribs and Sternum Spinal Column and Vertebrae

Axial Skeleton Skull Cranium houses and protects the delicate brain, while the facial bones guard and support the eyes, ears, nose and mouth Collectively there are 22 bones in the skull

The Skull

The Skull

Ribs and Sternum Ribs and sternum 12 pairs of ribs Sternum or breastbone divided into 3 parts

Spinal Column/Vertebrae Spine consists of small bones called vertebrae which are separated from each other by pads of cartilage tissue called intervertebral disks Five sections: cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacrum and coccyx

Appendicular Skeleton Upper Extremities Shoulder Girdle Arms Hand

Shoulder Girdle 2 clavicles (collar bones) 2 scapulae (shoulder bones)

Arms Humerus Radius Ulna

Hand 8 carpals (wrist bones) 5 metacarpals (hand bones) 14 phalanges (finger bones)

Skeletal System Appendicular skeleton (lower extremities) Pelvic girdle Ilium, Ischium and Pubis Legs Femur (thigh bone) Tibia and Fibula Patella (kneecap) Ankle 7 tarsal bones Calcaneus (heel bone) Foot 5 metatarsal bones (foot bones) 14 phalanges (toe bones)

Joints Called articulations Diarthroses (movable) joints Points of contact between two bones Diarthroses (movable) joints Amphiarthroses (partially movable) joints Synarthroses (immovable) joints

Diarthroses Joints Movable joints consist of three main parts Articular cartilage Articular capsule Synovial membrane Synovial fluid Synovial cavity Bursa sacs 4 types of diarthroses Ball-and-socket joints Hinge joints Pivot joints Gliding joints

Amphiarathroses Joints Partially movable joints Cartilage between their articular surfaces Examples: Ribs to the spine Symphysis pubis

Synarthroses Joints Immovable joints Connected by tough, fibrous connective tissue Example: Adult cranium Cranial joints called sutures

Types of Motion Flexion Extension Abduction Adduction Circumduction Rotation Pronation Supination