Bone Structure I Flashcards
6 Functions of the Skeleton
support, protection, movement, mineral storage/homeostasis, blood cell production, lipid storage
function of the skeleton - support - 2 points
framework to support soft tissue, point of attachment of muscles
function of the skeleton - protection - 1 point
to protect internal organs
function of the skeleton - movement - 2 points
bones = levers which muscles are attached, muscles contract to allow movement
function of the skeleton - mineral storage/homeostasis - 2 points
calcium/phosphorus, distributed on demand to maintain mineral balance
function of the skeleton - blood cell production - 2 points
Red marrow in certain bones produce RBCs, some WBCs and platelets
function of the skeleton - lipid storage - 1 point
yellow bone marrow serves as chemical energy reserve
2 types of connective tissue
cartilage and bone (the proportions of these 2 change as you grow)
Differences between cartilage and bone - 3 points
cartilage = tough/flexible/relatively light, bone = rigid/heavier/more resistant to deforming forces
Diaphysis
shaft of the bone
Epiphysis - 3 points
extremities of the bone, covered in articular cartilage, thin layer of hyaline cartilage where bone forms a joint with another bone
Metaphysis
where the diaphysis and the epiphysis meet
Epiphyseal Plate
only found in growing bone, where the metaphysis includes a layer of hyaline cartilage, where bone growth occurs
Epiphyseal Line
in adult bone, the hyaline cartilage at the metaphysis is replaced by bone
Medullary Cavity - 3 points
lies within diaphysis, lined with thin membrane = endosteum, contains fatty yellow bone marrow in adults
Periosteum - 2 points
tough sheath of dense irregular connective tissue, covers surface of bone not covered by articular cartilage
Role of Periosteum - 4 points
contains bone forming cells which enable bone growth in diameter (not length), protects the bone & assists in fracture repair, nourishes the bone tissue, serves as a point of attachment for muscles and tendons
Bone tissue
made up of matrix of extracellular material which surrounds widely separated cells
Matrix contains … 3 points
mineral salts (mainly Calcium Phosphate & some Calcium Carbonate), framework formed by collagen fibres, water
Ossification/Calcification
Salts are deposited in framework, they crystallise and the tissue hardens - initiated by osteoblasts
4 types of bone cell
Osteogenic cells, osteoblasts, osteocytes, osteoclasts
Osteogenic Cells - 2 points
found within periosteum, endosteum & canals within bone carrying blood vessels, cell division creates daughter cells which develop into osteoblasts
Osteoblasts - 4 points
bone-building cells, synthesise and secrete collagen & other components required to build matrix, initiate ossification, as osteoblasts secrete the matrix they become trapped - become osteocytes
Osteocytes - 3 points
mature osteoblasts which no longer produce new bone tissue, have long branching arms that connect them to neighbouring osteocytes - facilitates communication between them and metabolism of bone tissue by exchange of nutrients/waste with blood
Osteoclasts - 4 points
huge cells, mainly found in endosteum, derived from fusion of up to 50 monocytes (a type of WBC), where they face the bone surface their plasma membrane is folded to forma ruffled border, here powerful enzymes and acids breakdown underlying bone matrix - reabsorption (normal part of bone development/growth/maintenance/repair
Spaces in Bone act as …
storage areas - for red bone marrow, channels - for blood vessels supplying bone with nutrients
whether a bone is compact or cancellous depends on …
size and distribution of spaces in the bone
