6.1-6.3 Flashcards
Support, protection, assistance in movement, mineral homeostasis, blood cell production, and triglyceride storage
Functions of skeletal system
The skeleton serves as the structural framework for the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles
Support
The skeleton protects the most important internal organs from injury
Protection
Most skeletal muscles attach to bones; when they contract, they pull on bones to produce movement
Assistance in movement
Bone tissue makes up about 18% of the weight of the human body. It stores several minerals, especially calcium and phosphorus which contribute to the strength of bone. Bone tissue stores about 99% of the body’s calcium. On demand, bone releases minerals into the blood to maintain critical mineral balances (homeostasis) and to distribute the minerals to other parts of the body
Mineral homeostasis
Within certain bones, connective tissue called red bone marrow produces red blood cells, white blood cells, and platelets, a process called hemopoiesis. Red bone marrow consist of developing blood cells, adipocytes, fibroblasts, and macrophages within a network of reticular fibers. With age, much home marrow changes from red to yellow
Blood cell production
Yellow bone marrow consists mainly of adipose cells, which store triglycerides. The stored triglycerides are a potential chemical energy reserve
Triglyceride storage
The bone’s shaft or body; long, cylindrical, main portion of bone
Diaphysis
Proximal and distal ends ends of the bone
Epiphyses
In a growing bone, each metaphysics contains and epiphyseal plate, a layer of hyaline cartilage that allows the diaphysis of the bone to grow in length. When a bone ceases to grow in length at about ages 14 to 24, the cartilage in the epiphyseal plate is replaced by bone; the resulting bony structure is the epiphyseal line
Metaphyses
Thin layer on hyaline cartilage covering the part of the epiphysis where the bone forms an articulation (joint) with another bone; reduces friction and absorbs shock at freely movable joints. Lacks blood vessels and perichondrium
Articular cartilage
Tough connective tissue sheath and its associated blood supply that surrounds the bone surface where ever it is not covered by articular cartilage
Periosteum
Hollow cylindrical space within the diaphysis that contains fatty yellow bone marrow and numerous blood vessels in adults
Medullary cavity
Thin membrane that lines the medullary cavity. Contains a single layer of bone-forming cells and a small amount of connective tissue
Endosteum
Contains an abundant extracellular matrix that surrounds widely separated cells
Osseous tissue (bone)
Deposition of mineral salts, primarily hydroxyapatite, in a framework formed by collagen fibers in which the tissue hardens
Calcification
Unspecialized bone stem cells derived from mesenchyme. They are the only bone cells to undergo cell division; resulting cells develop into osteoblasts
Osteoprogenitor cells
Bone building cells; synthesize and secrete collagen fibers and other organic components needed to build the extracellular matrix of bone tissue and initiate calcification
Osteoblasts
Mature bone cells, are the main cells in bone tissue and maintain its daily metabolism such as the exchange of nutrients and waste from the blood
Osteocytes
Carve out bone. Huge cells derived from the fusion of monocytes and are concentrated in the endosteum
Osteoclasts
Strongest form of bone tissue; found beneath the periosteum of all bones and makes up the bulk of the diaphyses of long bones
Compact bone tissue
Basic unit of structure in adult compact bone
Osteons
Circular plates of mineralized extracellular matrix of increasing diameter, surrounding blood vessels and nerves located in the central canal
Concentric lamellae
Spaces between the concentric lamellae that contain osteocytes
Lacunae
