Chapter 6 Review - Bone Flashcards
Bone Function
1 Support 2 Protection 3 Movement 4 Mineral Storage/Homeostasis 5 Hemopoiesis 6 Triglyceride Storage
Support
structural framework for the body.
Protection
protects vital organs & tissues.
Movement
tendons insert into bone & produce movement at joints.
Mineral Storage/Homeostasis
Stores & releases minerals into blood.
Hemopoiesis
Red Bone Marrow produces all the blood elements.
Triglyceride Storage
Yellow marrow of diaphysis stores & releases fat.
Gross Anatomy
206 bones in the body characterized by their shape.
Bone Shape
Long Bones Flat Bones Sutural Bones (wormian) Irregular Bones Short Bones Sesamoid Bones
Long Bones
slender bones of arms, legs, hands, fingers, feet, toes, etc.
Diaphysis, Epiphysis, Metaphysis
Diaphysis
cylindrical shaft of compact bone with a central yellow marrow containing fat. Made up of osteons running in a parallel direction.
Epiphysis
tips of long bone made of spongy (cancellous) bone w/ osteons. Spongy bones are made of struts of bone called trabeculae and the space between is red marrow which functions in hemopoeisis.
Metaphysis
is the region which joins the epiphysis to the diaphysis and contains the growth plate (epiphyseal plate) in growing bone.
Articular Cartilage
tips of epiphysis which articulates with other bones will contain hyaline cartilage:
- Shock absorption
- Reduce friction during movement.
Periosteum
Outermost layer covering the whole bone (except at articulations which have a perichondrium covering articular cartilage). It serves as site of attachment for tendons & ligaments where they are reinforced to the bone by Sharpey’s fibers. Made of two layers:
- Outer layer
- Inner layer
Endosteum
incomplete cellular layer lining the medullary cavities (red & yellow) and participates in bone growth, repair & remodeling
- Osteogenic progenitor cells are present to replace bone
- Osteoclasts present in endosteum spaces to breakdown bone.
Shock Absorption
displacing the weight load over larger surface.
Periosteum Inner Layer
- cellular layer w/osteogenic progenitors to form osteoblasts.
Periosteum Outer Layer
- dense irregular CT
Flat Bones
thin parallel surfaces of roof of skull, scapula, ribs, coxa bone, etc.
Sutural Bones (Wormian)
small flat irregular shaped bones between flat bones of skull (fit like jigsaw puzzle).
Irregular bones
have complex shape as with vertebrae.
Short bones
short boxy bones seen in carpal & tarsals of wrist & ankle.
Sesamoid bones
flat irregular bones which develop in tendons (eg- patella)
Surface Markings
appear on surface owing to physical demands of a given region:
- Rough irregular raised surfaces
- Depressions (fossa) & Grooves (sulcus)
- Tunnels (foramen or canal)
Rough irregular raised surfaces
point of attachment for tendons or ligaments seen as tuberosity, trochanter or tubercle.
Depressions and Grooves
indicates site for nerves or blood vessels.
Depressions
fossa
Grooves
sulcus
Tunnels
foramen or canal
- serves as passageway for nerves or blood vessels.
Histology of Bone
Bone is either compact or spongy. It is largely a calcified matrix with a relatively small number of cells.
Matrix of Bone
50% crystallized mineral salts, 25% collagen & 25% water.
- Collagen
- Hydroxyapatite
- Ossification
Collagen
the fibrous protein that provides the framework for bone.
Hydroxyapatite
crystal from calcium phosphate & calcium hydroxide.
Ossification
process by which minerals crystallize to harden the matrix.
Cells of Bone
Four cells in bone:
- Osteoprogenitor cells
- Osteoblasts
- Osteocytes
- Osteoclasts
Osteoprogenitor cells
mitotically mesenchymal stem cells which differentiate into osteoblasts. Important for growth & repair.
Osteoblasts
responsible for osteogenesis by synthesizing both osteoid matrix & collagen. After laying down osteoid material, they mature into osteocytes.
Osteocytes
are the mature bone cells that sit in lacunae and communicate via canaliculi to help maintain bone metabolism by exchanging nutrients & wastes.