Skeletal

Quiz on the sketal system

Skeletal System Functions

Support, Protection, Movement, Mineral Storage, Site of Blood Cell Production, and Energy Storage

Components of Compact Bone

Few Spaces

External Portion of Bone

Compact Bone

Shaft of Long Bone

Consisted of Compact bone—offers protection and support, Nutrients arteries through canals

Haversian Canals vs

Haversian canals provide nutrition and support to bone cells, while Volkmann's canals connect Haversian canals to the bone's surface

Lamellae

Layers around the Haversian Canal

Periosteum

Membrane on the surface of the bone

Spongy Bone

Usually does not contain osteons

Latticework of Bones

Trabeculae (also contain osteocytes and lacunae)

Spaces within Trabeculae

Red Bone Marrow

Location of Spongy Tissue

Short, flat, irregular bones, epiphyses

Central Medullary Cavity

Contains bone marrow

Marrow

Contains two types of stem cells, produces hematopoietic stem cells (HSC) prior to birth

Daily Blood Cell Production

Several million

Components of Red Marrow and Yellow Marrow

Red marrow contains all blood cells, platelets form; Yellow marrow contains 30% lymphocytes, may revert to red if blood deficiency

Osteoporosis

Bone decay

Types of Bones

Long, short, flat, irregular (also sutural and sesamoid)

Diaphysis

Shaft of long bone

Epiphyses

Ends of bone

Metaphyses

Where epiphyses and diaphyses meet

Articular Cartilage

Hyaline cartilage at the end of epiphysis that connects to another bone, helps with friction

Outer Layer of Periosteum

Contains blood vessels and nerves, not covered by cartilage

Inner Layer of Periosteum

Elastic fibers, cells necessary for growth and repair

Medullary Cavity

Cavity within diaphysis, contains yellow bone marrow

Endosteum

Medullary Cavity, contains osteoprogenitor cells which will become osteoblasts

Short Bones

Cube-shaped, equal in length and width, spongy with surface of compact bone (e.g wrists and ankles)

Flat Bones

Thin, composed of two parallel plates of compact bone that enclose spongy bone, protect (e.g cranial, sternum, ribs)

Irregular Bones

Vary in shape, amount of spongy (e.g vertebrae, hip, some facial bones)

Sutural Bones

Small bones between joints of some cranial bones, number varies person to person

Sesamoid Bones

Small bones in tendons where pressure develops, number varies by individual (e.g patellae, kneecaps)

Osteoprogenitor Cells

Cells that produce osteoblasts through mitosis

Osteoblasts

Form bone, maintain collagen, repair

Osteoclasts

Develop from white blood cells, secrete digestive enzymes to break down bone

Matrix

Consists of salts (calcium phosphate, calcium carbonate)

Intramembranous Growth

Originate in sheet-like layers in CT, usually flat bone

Steps of Intramembranous Growth

Cells in mesenchyme form into osteoprogenitor cells, osteoblasts and vessels surrounded by calcified matrix, trabeculae result, osteoblasts become trapped lacunae and form osteocytes, CT becomes periosteum

Endochondral Growth

Cartilage decomposes, periosteum forms from CT around developing structure, cells form spongy bone where cartilage once was, osteoblasts form compact bone around spongy bone, band of cartilage remains between epiphyses

Remodeling

Only bone tissue replaced by new bone tissue

Hematomas

Blood pocket around break

Homeostasis

Maintained between osteoclasts (extracting calcium) and osteoblasts (producing calcium)

Bone's Role

Calcium storage for the body

Bone Tissue Destruction

Osteoclasts remove calcium from bone when needed