THE SKELETAL SYSTEM CH. 6 INTRODUCTION TO CHAPTER

WHY DO WE NEED A SKELETAL SYSTEM? It provides a framework for the body and gives it shape It supports organs and protects them from injury It provides a place for muscles, ligaments, and tendons of the body to attach to It helps to make movement possible It stores minerals It provides a place for hematopoiesis

WHAT IS BONE AND WHAT IS IT MADE OF? Bone is one of the types of connective tissue in the body CONNECTIVE TISSUE is the most widespread tissue and provides a framework for animals. Connective tissue holds organs in place and connects body parts to each other.

WHAT IS BONE AND WHAT IS IT MADE OF? It is also called OSSEOUS tissue It is made up of water and mineral salts OSSIFICATION is the formation of or conversion into bone or a bony substance (calcification is the deposition of calcium in a tissue)

WHAT IS BONE MADE OF? The outer surface is called COMPACT BONE and is very dense. It is the thickest in the midshaft of a long bone to provide strength and prevent bending of the bone The inner layer is called CANCELLOUS BONE and is spongy and latticelike and is less dense than compact bone

WHAT IS BONE MADE OF? The SHAFT (DIAPHYSIS) of the bone contains the MEDULLARY CAVITY It is filled with YELLOW MARROW (fat storage) and RED MARROW (hematopoietic tissue) Yellow marrow replaces red marrow as an animal ages. In an adult, red marrow is found in cancellous bone in the skull, pelvis, vertebrae, ribs, sternum, and epiphysis of the humerus and femur

WHAT IS BONE MADE OF? PERIOSTEUM covers the surface of bone and is a tough, vascular membrane. It is where tendons, ligaments, and muscles attach to the body. It has a nerve and blood supply. The inner layer of the periosteum contains OSTEOBLASTS which are cells responsible for bone growth and repair.

WHAT IS BONE MADE OF ? The medullary cavity of bone has arteries and veins that enter and exit the cavity via the nutrient foramen which are openings in the bone

HOW DO BONES GROW? They grow in LENGTH at the junction of the EPIPHYSIS and the DIAPHYSIS at the epiphysial plate (growth plate). It is also called the PHYSIS They grow in THICKNESS in the layers of the periosteum.

HOW DO BONES GROW? Bones are stimulated to grow via GROWTH HORMONE (GH) which is produced by the pituitary gland.

HOW DO BONES GROW? There is a teamwork between osteoblasts producing bony tissue and osteoclasts eating away bony tissue to prevent the bone from becoming too thick. This process slows as an animal ages.

SHAPES OF BONE LONG (femur, humerus) FLAT (sternum, scapula) SHORT (carpal bones) IRREGULAR (vertebrae)

PARTS OF THE SKELETON Before learning the names of specific bones, think of the skeleton as being made up of 2 parts: AXIAL APPENDICULAR

AXIAL SKELETON SKULL, HYOID BONE, VERTEBRAL COLUMN, RIBS, STERNUM

APPENDICULAR SKELETON BONES OF THE LIMBS: CLAVICLE, SCAPULA, HUMERUS, RADIUS, ULNA, CARPUS, METACARPALS, PHALANGES, PELVIS, FEMUR, PATELLA, TIBIA, FIBULA, TARSUS, METATARSALS