Ligaments And Tendons Flashcards
What do tendons connect?
Muscle to bone
What do ligaments connect?
Bone to bone
What are ligaments function?
*Augment STATIC MECHANICAL STABILITY OF JOINTS
*PREVENTS XS ABNORMAL MOTION
SENSORY SOURCE, PROVE PROPRIOCEPTION FEEDBACK
What is the function of tendons?
TRANSMIT TENSILE LOAD TO BONE
ENABLE MUSCLE TO BE OPTIMAL DISTANCE FROM JOINT
STORE ENERGY
What are ligaments and tendon made of?
PARATENON- loose areolar tissue, protects and facilitates gliding. Major site of remodelling and healing responses- abundant cells and blood vessels (vascular tendons ) some tendons a synovial sheath replaces the paratenon - AVASCULAR tendons
EPITENON- a SYNOVIUM like membrane beneath paratenon for tendons with high frictional forces in Palm - increase gliding, by producing SYNOVIUM form synovial cells
ENDOTENON- binds fascicles ( groups of collagen bundles )
MICRO= Cells-FIBROBLASTS Extracellular matrix- COLLAGEN 1( 70% tendons ) GROUND GLASS ELASTINS ( > LIGAMENTS)
How is collagen synthesised?
As a PRECURSOR, PRO-COLLAGEN by FIBROBLASTS
SECRETED and CLEAVED extracellularly-> COLLAGEN
What type of collagen is within ligaments and tendons?
Type 1- 90%
How does collagen exist?
As 3 POLYPEPTIDE CHAINS
2 alpha 1
1 alpha 2
COMBINED TO FORM A RIGHT HANDED TRIPLE HELIX-> collagen molecule a ROD like shape
What are the x linkage between collagen molecules due to ?
Hydrogen bonds
What do several collagen fibres aggregate to form?
MICROFIBRILS (0.02-2um) in a quarter staggered way
What are further aggregation of MICROFIBRILS called?
Collagen fibres (1-20um) and bundles
What are lined between these bundles?
Fibroblasts in the direction of the ligament/ tendon function
What is the direction of collagen fibres in tendons? Why is this?
Parallel
To allow them to handle UNIDIRECTIONAL TENSILE LOADS
What direction are the collagen fibres in ligaments? Why is this?
Less parallel in layered arrangement with a single layer of fibres lying parallel but in subsequent layers they lie at different directions. Also crimped ( wavy pattern) to increase their capacity to absorb tension
To allow these structures to SUSTAIN PREDOMINANTLY TENSILE STRESSES IN 1 DIRECTION but also SMALLER STRESSES IN OTHER DIRECTION for any applied external force
What does the ground substance consist of? Can you draw it?
PROTEOGLYCANS
GLYCOPOROTEINS
PLASMA PROTEINS
What is the role of the PROTEOGLYCANS ?
That bind Extracellular water making the matrix a highly structured gel like material.
It also STABLISES the collagenous skeleton of the ligaments and tendons and contributes to overall strength
What is ELASTIN?
A HYDROPHOBIC NON GLYCOSLATED PROTEIN secreted by FIBROBLASTS into the Extracellular matrix