Chapter 6 & 7 - Bone Tissue + Axial Skeleton Flashcards
Distinguish between **bone **as a **tissue **and as an organ
bone is composed of several different tissues working together: bone, cartilage, dense connective, epithelium, adipose & nervous tissue
therefore, each bone in your body is considered an **organ **
Functions of **Bone & Skeletal System **(6)
1) support - structural framework
2) protection - protects internal organs
3) assistance in movement - skeletal muscle contract & pull on bones to produce movement
4) mineral homeostasis (storage & release) - bone tissue stores mineral
5) blood cell production
6) **triglyceride storage **- yellow bone marrow consists of mainly adipose cells
**Structure of Bone (7) **
1) Diaphysis
2) Epiphyses
3) Metaphyses
4) articular cartilage
5) periosteum
6) medullary (marrow) cavity
7) Endosteum
1) Diaphysis
bone shaft or body
2) Epiphyses
proximal & distal ends of bone
3) Metaphyses
regions between diaphysis & epiphysis
contains epiphyseal (growth plate)
when bone stops growing in length ,cartilage in epiphyseal plate is replaced by bone - epiphyseal line
4) articular cartilage
thin layer of hyaline cartilage covering part of epiphysis where bone forms an articulation (joint) with another bone
5) periosteum
tough connective tissue sheath and its associated blood supply that surrounds bone surface wherever it is not covered by articular cartilage
outer fibrous layer & inner osteogenic layer
6) medullary (marrow) cavity
hollow, cylindrical space within diaphysis that contains fatty yellow bone marrow & humerus blood vessels in adults
7) Endosteum
thin membrane that lines medullary cavity
- contains a single layer of bone‐forming cells and small amount of connective tissue.
Like other connective tissues, **bone (osseous tissue) **congtains an abundant ..?
extracellular matrix that surronds widely separated cells
**Extracellular Matrix **
made up of?
15% water
30% collagen fibers
55% crystallized mineral salts
The most abundant mineral salt in bone is?
calcium phosphate
calcification
calcium phosphate combines with calcium hydroxide to form hydroxyapatite
as crystals form, they combine with other mineral salts (calcium carbonate, Mg, F, K & sulfate ions)
as these mineral salts are deposited & crystalzie in framework formed by collagen fibers of ECM
initiated by **osteoblasts **(bone-building cells)
Calcification is initiated by?
**osteoblasts **- bone-building cells
Bone’s flexibility depends on?
collagen fibers
(4) types of cells present in bone tissue
1) osteogenic
2) osteoblasts
3) osteocytes
osteoclasts
osteogenic cells
Undergo cell division
the resulting cells develop into **osteoblasts **
(unspecialized bone stem cells)
osteoblasts
Bone-building cells
synthesize extracellular matrix of bone tissue
become osteocytes
Osteocytes
mature bone cells
exchange nutrients & wastes with blood
(main cells in bone, maintain daily metabolism)
Osteoclasts
huge cells derived from fusion of as many as 50 **monocytes **(type of white blood cell)
Release enzymes that digest the mineral components of bone matrix (resporption)
regulate blood calcium level
(2) categories of bone
1) compact
spongy
Compact bone
resists?
components?
these consist of?
Resists the stresses produced by weight and movement Components of compact bone are arranged into repeating structural units called **osteons **(Haversian systems)
Osteons consist of a central (Haversian) canal
- run longitudinally through bone
- with concentrically arranged lamellae, lacunae, osteocytes, and canaliculi
Lamellae
part of osteon, concentric **lamallae **are around central canals
rings of calcified matrix (like rings of tree trunk)