Skeleton Flashcards
What is a skeleton?
Comprised of cartilage and bone- both are rigid tissues
however only bone is mineralised
What is cartilage
Consists of:
chondoblast cells which secrete ground substance and collagen- Rigid gel
The cells remain in situ as CHRONDOCYTES
Structural glycoproteins- it is the glue holding the fibres and proteoglycans together
perichondrium- surrounds the cartilage- bringing nutrients to it
ECM- deformable- so when cartilage deforms, proteoglycans (hydrophilic) give away some some of the fluid . But when pressure is removed, proteoglycans take in some fluid
There are no neurovascular elements within cartilage-
hence it gains nutrients through diffusion- therefore
cartilage tend to be thin in certain area
What is the function of bone?
Support- rigid framework for the support of the body
Movement- bones are acting as the levers for muscles
Protection- bones can form a box to protect delicate strictures
Homophioesis-principle the blood cells are formed in bone marrow
Storage- Calcium and Phosphorus are stored in the body-
Calcium in the blood must be kept constant- required for muscle contraction and required in junctions between cells. Therefore it must be stored until required
What are the two types of bones in regards to region
Axial- core- trunk skull
Appendicular- everything which sticks out
What are the different types of bone in regards to shape
long bone (humerus) short bone (trapezoid, wrist bone) flat bone (sternum) irregular bone (vertebra) sesamoid bone (patella- responsible for straightening the leg- inside the quadricep muscle and is part of the tendon- this decreases the wear and tear of the muscle)
How do you classify bone by origin
Endochondral - the precursor is cartilage which is used as a template
intramembrous
What are the two parts of mature bone?
Compact- appear relatively solid
Trabecular- appear as an open network of struts
(Needs a blood supply)
Describe compact tissue structure
Highly organised tissue osteon forming functional unit - within each osteon, osteocytes are arranged in concentric layers around a central canal containing a blood vessel which supplies the osteon.
These canals run parallel to the surface of the bone-perforating canals which are roughly perpendicular to the osteons delivering blood deeper into the bone
Overall its structure allows it to resist the stress that comes form limited number of directions. (shaft of a bone)
THICKEST WHERE THE FORCES ARE GREATEST
Describe the trabecular tissue structure
its elements form struts and plates- is lighter than compact
The trabeculae are organised to ensure that the bone is strong enough to resist forces that act on it
The structure allows it to resist stresses in more than one direction- found in the epiphysis of long bones where trabeculae are aligned along stress lines. The structure allows it to protect bone marrow
HEAD
The expanded head of the epiphysis separated from the shaft by a narrow neck
NECK
a narrow connection between epiphysis and the diaphysis
CONDYLE
a smooth round articular process (condylus - knuckle)
TROCHLEA
type of condyle- smooth grooved articular process shaped like a pully
FACET
a small flat articular surface
PROCESS
any projection/bump
