TISSUE TYPES- BONE Flashcards
Where is the periosteum found
Covers the outer surfaces of bones
What is the structure and function of the periosteum
- Is a tough fibrous membrane
- Forms bone during development (also in the healing of a fracture )
What is compact bone
Solid bone consisting of lamellar bone arranged around closely packed osteons or haversian systems
What is cancellous bone
Spongy bone
Has varying density
What is the medullary cavity
Contains bone marrow - fat in older animals
Produces red and white blood cells
What is the axial skeleton
The bones forming the axis or centre of the animal.
E.g. bones f the head, neck, vertebrae column, ribs, (pelvis) and tail.
What is the appendicular skeleton
Regions that are attached
E.g. bones of the forelimbs and hind limbs
What are visceral bones
Develop inn the soft tissues, away from the rest of the skeleton
Give 2 examples of visceral bones
Os penis. Inn the dog and cat
Os cordially in the heart of ruminants
What are the different types of bones
Long bones Short bones Flat bones Sesamoid bones irregular bones
What are the main features of a long bone
Cylindrical shape
Main part of bone is a column providing strength, expanded ends providing transfer of load
Resist compression when loaded, act as levers and resist tension during uncle contraction
Which cells make up bone
Osteoblasts
Osteocytes
Osteoclasts
What do osteoblasts do
Synthesise and secrete osteoid
What do osteocytes do
Maintain matrix
What do osteocytes do
Responsible for bone reasorbtion - get rid of old bone to make new osteons
Where would you find osteocytes
Scattered within matrix
Reside within lacunae (little holes) which are interconnected by canaliculi
What do osteoclasts look like
Are large cells with multiple nuclei
What makes up the inorganic component of bone
Minerals
Calcium and phosphorous
Make bone radio-opaque
What makes up the organic part of the bone matrix
Osteoid
Glycoproteins
Proteoglycans
Bone sialoproteins
What makes up the osteoid
Collagen type 1
Strong inert fibrils
What does glycoproteins do in the bone matrix
Binds collagen and mineral
What do proteoglycans do in the bone matrix
Bind growth factors
What do bone sialoproteins do in the bone matrix
They are associated with cell adhesion
What are the 2 types of bone tissue
Woven Bone
Lamellar bone
What is woven bone
Quick and dirty formation
Occurs in young growing animals and during fracture repair
Mineralises quickly
What is lamellar bone
Replaces woven bone
Parallel fibres make this type of bone structurally superior
What is another name for a haversian system
Osteon
How are primary osteons formed
Formed when bone is growing
Osteoclasts excavate cylindrical tunnel
Osteoblasts follows, form concentric lamellar of lamellar bone on walls, surrounding a centrally in- growing blood vessel
What is different about secondary osteons
Formed the exact same way just come off the primary osteon
What are the two types of ossification
Endochondral ossification
Intramembranous ossification
What is endochonral ossification
In direct
Cartilage is invaded by vessels and undergoes mineralisation
Occurs in the growth plates
What is intrmembranous ossification
Direct
Mesenchymal cells differentiate into osteoblasts and produce bone directly
No pre-existing cartilage model
What does endochonral ossifaction form
Length growth in long bones
What does intramembranous ossification form
Flat bones ( e.g. most of skull ) Width growth in long bones
What are the main parts of the haversian system
Haversian canal Lamellae Lacunae Osteocytes Canaliculi
What is the Haversian canal
Longitudinal canal in the center of haversian systems. Contains blood vessels and nerves
What are lamellae
Concentric rings of calcified matrix around the Haversian canal
What are lacunae
Cavities within lamellae that contains osteocytes
What are canaliculi
Small canals that radiate from he Haversian canal and interconnect lacunae with each other
Why is bone remodelling important
Changes the bone shape
Changes the bone material
Repairs damaged bone
Releases mineral ions
What is the main differences between bone and cartilage
Bone is highly vascularised however cartilage is a vascular
Bone is very strong and cartilage is flexible and resistant to compressive forces
What are stress fractures
Syndrome involving localised bone injury associated with fatigue damage subsequent to repetitive loading
