Skeletal
osteoblasts
bone bulding cells, synthesize extacellular matrix of bone tissue
most abundant mineral salt
calcium phosphate. can be fluoride, potassium, magnesium.
2. growth of the cartilage
a) inerstitial growth-chondroblasts then mature into chondrocyes allowing for growth in length. b) appositional growth- perichondrium secrets matrix, creating chondroblasts to condrocytes allowing growth in width.
diaphysis
...
ephiphysis
...
histology of bone tissue
4 types are present in done tissue. osteogenic cells, osteoblasts, osteocyes, and osteoclasts
bone deposition
addition of minerals and collagen fibers to bone by osteoblasts
appendicular skeleton
appendages and girdles
movement facilitation
assist muscles to produce movement of body parts
osteons
basic unit, contain blood vessels, nerves, osteoytes, and matrix
hemopoiesis
blood cell production; occurs in red marrow
osteoporosis
bone disorder; done resoprtion outpaces bone deposition
axial skeletal
bones of the midline
haversian canal
center os osteon; contains nerves and vessels
osteons
central(haversian) canal with cocentrically arranged lamellae, lacunae, osteocytes, and canaliculi.
clavicle
collar bone
spongy bone
contains all structures of compact bone EXCEPT osteons
collagen fiber
contribute to tensile strength(flexibility)
periosteum
covering of the bone
mineral salts
deposited and crystalize in the framework formed by the collagen fibers of the extracellular matrix; contribute to hardness of bone.
structure of long bone
diaphysis, epiphysis,metaphysis, articular cartilage, periosteum, medullary cavity, endosteum
pelvic/hip gridle
each side made of three bones that meet at the acetabulum and join at the pubic symphasis. Illium- largest Ishium-posterior and inferior Pubis-anterior inferior
5. secondary ossification center
epiphyseal artery enters the epiphyses( around birth) bone formation only spongy bone.
metaphysis
epiphyseal growth plate
factors affecting bone growht and remodeling
exercise-increases process of osteoblasts sedentary-slows process of bone formation diet- VA-stimulates osteoblasts. VC- synthesis collagen. VD-build bone. hormones. PTH decreases calcium in bone; calcitonin increases calcium, increases osteoblasts
canaliculi
extensions from osteocyte (radiating canals)
3) formation of trabeculae
extracellular matrix forms and develops into trabeculae which fuse together to form spongy bone
epiphyseal and metaphyseal
follow named artery
nutrient veins
follow named artery
nerves
follow vessles into bone and periosteum where they sense damage and trasmit pain messages
intramembranous ossification
formation fo bone directly from or within fibrous connective tissue. forms flat bones of the skull and mandible
endochondral ossification
formation of bone from hyaline cartilage models
1) development of occification center
forms from mesenchymal cells when they convert to osteoblasts and lay down matrix.
function of spongy bone
forms interior structure of shorts, flat, and irregular bones as well as the epiphyses of long bone
Skeletal System
framework of bones and cartilage that protects our organs and allows us to move
medullary cavity
hollow part of the diaphysis; bone marrow
6. articular cartilage and epiphyseal plate
hyaline cartilage covering epophyses becoming articular cartilage; epiphyseal plat is between epiphysis and diaphysis.
osteomalacia
inadequate calcification due to Viatimin d deficiency
endosteum
inside the medullary cavity
bone formation
intramembranous ossification and endochondral ossification
clacification
is initiated by bone building cells called osteoblasts
types of bones
long. short. flat. irregular. sesamoid.
trabeculae
makes bone lighter and is sometimes filled with red bone marrow. oriented along lines of stress; helps bones resist stresses without breaking.
2) calcification
matrix surrounds the cell, then calcifies as osteoblasts becomes osteocytes
osteocytes
mature bone cells, enchance nutrients and waste with the blood
1. cartilage model
mesenchymal cells develop into chondroblasts which then secretes matrix that forms hyaline cartilage periosteum then covers the outside.
3. primary ossification
nutrient artery penetrates perichondrium and catilage about midrang. perichondrium stiumulates osteoblasts to matrix over calcified cartilage, forming trabeculae.
venous supply
nutrient veins, epiphyseals and metaphyseal, nerves.
bone remodeling
ongoing replacement of old bone tissue by new bone tissue
4. medullary cavity
osteoclasts break down some newly formed trabeculae causign a cavity in the diaphysis most of the wall becomes compact bone.
articular cartilage
perforating fibers, prevent friction
4) development of periosteum
periphery of spongy bone forms then eventually is replaced by compact bone; spongy bone is left in the center
triglyceride storage
potential energy reserve
lamellae
produced around osteocytes (hard rings)
support
provides attachment sites for muscles and supports soft tissue
protection
provides bony covering for many of the body organs
nutrient artery
provides nutrients for osteocytes
osteoclasts
releases enzymes that digest the mineral components of bone matrix(resorption); regulate blood calcium level. break down bone tissue.
bone resportion
removal of minerals and collagen fibers from bone by osteoclasts
compact bone
resists the stress produced by weight and movement. components of compact bone are arranged into repeating structural units called osteons or haversian systems.
pectoral/ shoulder bone
scapula, clavicle
lacunae
space that contains osteocytes
scapula
spine-posterios gelnoid fossa- articulates with head of humerus acromion-superior; high point where scapula and clavicle articulate coracoid-anterior and lateral
storage
stores and releases minerals to maintain homeostasis
epiphyseal artery
supplies marrow and osteocells
periosteal arteries
supply compact bone
functions
support, protection, movement facilitation, storage, hemopoiesis, and triglyceride storage.
extracellular matrix
surround widely separated cells. 25% water, 25% collagen fibers, 50% crystallized mineral salts
bone formation (osteogenesis: ossification)
to grown/generate. 1.formation of bone in an embryo. 2.growth of bones until adulthood. 3.remodeling the bone. 4. repairing of fractures
balance must exist between osteoclasts and osteoblast
too much new tissue formed causes bone to be abnormally thick and heavy; excessive loss of calcium weakens the bone as in osteoporosis; may become too flexible, as in rickets and osteomalacia(lack of Vitamin D)
osteogenic cells
undergo cell division, the resulting cells devlop into osteoblasts