6 main functions of the skeletal system Support: support of soft tissue and attachment points for tendons Protection: internal organs from injury Assistance in movement: skeletal muscles pull on bones upon contraction to produce movement Mineral Homeostasis: storage of Ca and P to strengthen bone. Release from bone into blood to Maintain critical mineral balances and distribute to other parts of the body Hemopoiesis: blood cell production Triglyceride Storage: yellow bone marrow
What types of tissues make up the skeletal system? Bone, cartilage, dense connective tissue, epithelium, various blood forming tissues, adipose tissue, and nervous tissue.
How do red and yellow bone marrow differ in composition and function? Red bone marrow: produce red blood cells, white blood cells, and platelets Yellow bone marrow: adipose cells that store triglycerides and potential energy reserve
Describe the structure and functions of each part of a long bone Diaphysis: main portion of bone, the shaft Epiphyses: proximal and distal end of bone Metaphyses: regions between Diaphysis and Epiphyses, contains epiphyseal plate Articular cartilage: thin layer of hyaline cartilage covering part of epiphysis where joint is to reduce friction and absorb shock at freely movable joints Periosteum: surrounds external bone surface wherever articular cartilage is not. Protects bone, assists in fracture repair, nourish bone tissue, and attachment for ligaments & tendons Medullary Cavity: marrow cavity within Diaphysis Endosteium: thin membrane lining internal bone surface facing medullary cavity Why is bone considered a connective tissue? Bone is made of many cells connected together by an extracellular matrix made of collagen fiber adding in support and elastic fibers adding in flexibility
What factors contribute to the hardness and tensile strength of bone? Hardness: crystallization of inorganic mineral salts Tensile Strength: collagen fibers and other organic molecules
List the four types of cells in bone tissue and their functions
Osteoprogenitors: immature bone cells from mesenchyme, can become osteoblasts Osteoblasts: from Osteoprogenitors, build bone, on surface of bone Osteocytes: from osteoblasts, mature bone cells, maintain bone tissue Osteoclasts: break down bone via alkaline phosphatase, remodeling
What is the composition of the extracellular matrix of bone tissue? Mineral Salts: 40% dry mass Calcium Hydroxyapatite (most abundant) Ca10(PO4)6(OH)2 Calcium Carbonate CaCO3 Magnesium Hydroxide Mg(OH)2 Protein fibers: 60% dry mass Collagen (most common): flexible and tensile strength
How are spongy and compact bone tissues different in microscopic appearance, location, and function? Compact Bone: located in surfaces of shafts, gives strength and support, arranged with osteons Spongy Bone: located interiorly, site for Hemopoiesis, arranged with trabecule, surrounded by red bone marrow, with no true osteons
Describe the blood and nerve supply of bone. Periosteal Arteries: supply periosteium Nutrient Arteries: enter through nutrient foramen, supplying compact bone of diaphysis and red marrow Metaphyseal & Epiphyseal Arteries: supply red marrow and bone tissue of epiphyses
Which part of a bone contains sensory nerves associated with pain? Describe one situation in which this is important. The periosteum, pain from a bone tumor would be an indicator of the cancer that without pain a diagnosis may not have occurred.
Where do periosteal arteries enter bone tissue? Through the nutrient foramen
Describe the steps of intramembranous and endochonral ossification. Intramembranous Ossification: 1. Development of the ossification center: mesenchymal cells differentiate into osteogenic cells and then into osteoblasts 2. Mineralization: extracellular matrix stops, Osteocytes lie in lacunae. Ca and other mineral salts are deposited