Final.tendons

Question 0

Tenocytes contain and function

Answer 0

Tendon cells - well-developed RER

Synthesis and turnover of tendon fibres and ground substance.

Question 1

Tenocytes are?

Answer 1

Sumerman like cells.
Quintescent cells
Elongated fibroblast like cells
Important - maintains tendon function

Question 2

Tendon composition

Answer 2

Tenocytes 3% arranged in rows between col fibres
ECM - Col fibre - 65-85%
Elastic 1-2%
Ground substance

Question 3

Tendon ground substance

Answer 3

GAGs, proteoglycans, glycoproteins 0.2-5%

Question 4

Tendon hierarchical structure (5)

Answer 4

Arranged similar to muscle and nerve
Glycine, proline, hydroxy proline
Collagen fibre bundles surrounded by - CT
Only endo and epi tenon. CT
paratenon in fascia surrounding. 3rd. External layer - lct (fatty areolar)

Question 5

Tendon ecm contains?

Answer 5

Collagen, pg and gags

Question 6

Longitudinal and transverse collagen

Answer 6

Longi - 300um. Length. 1.5um height - triple stranded collagen molecule.
Transverse - 2 a2 and 1 a1 strands. Surrounded by pg and gsgs

Question 7

Tendon strength dependent on?

Answer 7

Number, arrangement, position and size of collagen

Fibrillar organisation and thickness

Question 8

Size on tendon depends on?

Answer 8

Collagen fibres

Question 9

Largest tendon and has the?

Answer 9

Achilles

Largest collagen fibres

Question 10

Ruture of tendon->

Answer 10

Decrease in collagen size

Question 11

Tendon -> h and e -> LM

Answer 11

wavy morphology
Collagen strain - sirius red
Crimps - observe at em - wavy morph of coll fiber - due to planar undulations

Question 12

tendon stretches, the muscle function with less change in length, allowing the muscle to generate greater force.

Answer 12

Tendon functions with,uscle

Question 13

Crimps (3)

Answer 13

-Important stretch/stim by mechanotransduction
-Collagen fibres some flexibility - absence of hydroxyproline and proline specific location at aa sequence
Maintain homeostasis of tissue

Question 14

Why tendon not completely elastic?

Answer 14

Lack of elastic fibres - greater amount of collagen

Question 15

What is the crimp angle?

Answer 15

Tendon sinusoidal stretch curve.

Specific for each tendon

Question 16

Ruptured tendon and crimp angle

Answer 16

Lower crimp angle

Question 17

Tendon ecm (2)

Answer 17

Elastic fibres - recovery of waxy collagen fibre

Pg (4)

• bind water - mech stim - water moved from one compartment to another
• lubricate movement
• regulation of fibrillogenesis
• stabilisation of whole collagen system

Question 18

Ligaments (2) difference between them and tendon fibres

Answer 18

Collagen fibres not completely parallel

Greater no. Of elastic fibres

Question 19

Tendons, ligaments, fascia and each connections (3)

Answer 19

T muscle to bone
L bone to bone
F muscle to muscle

Question 20

Tendon load deformation curve

Answer 20

Stress strain.
Physiological - 2%
Overuse - 5%
Rupture - 10

Toe, linear, partial failure, complete rupture

Question 21

Tendon 3 sections

Answer 21

Myotendonous substances - inserted intoo deep recesses - formed by myocyte processes
Midsubstance - t1 (60%), t3-8, GAGS, glycoproteins, PGs
Osteotendinouus substance - same of mid + T2 collagen. Fibrouos ct, immineralised fibrocart, mineralised to cart bone

Question 22

• Two Forms of Tendon Healing may occur:

Answer 22

Intrinsic - w/o blood flow - synovial fluid diffusion - no adhesion

Extrinsic - fibroblast proliferation - adhesion

Question 23

Blood supply of tendons

Answer 23

Limited.
Via peritenon
Digits -> vinicula (folds of mesotenon penetrate tendon)

Question 24

Tendoblasts and under pathological conditions ?

Answer 24

Active, rounded - proliferation (maintains normal homeostasis)

Pathological - increase in no.

Question 25

Tenocytes (1)

Answer 25

Low rate proliferation
Collagen syn, degradation, mechanotranduction (actin), cell to cell occluding junctions.
Gap junctions, adheren junctions

Question 26

Collagen turnover synthesis!

Answer 26

TGF B1 (cytokinin) -> LH

Question 27

Collagen turnover - degradation

Answer 27

MMP pathway - mrna, prommp, mmp, active mmp -> col 1 + ecm degradation.
Timp inhibits mmp
Tissue inhibiting mellatoprotease

Question 28

How does tgf b1 work?

Answer 28

Inhibitor of enzyme involved in col and ecm degradation

Question 29

Tendon not static

Answer 29

When repetitive mechanical loading of tendon:
Cellular matrix response -> adequate -> adaptation.
Inadequate -> transient weakness in tendon -> if cont and exceeding tendon healing capacity -> overuse injury

Question 30

Tendon stress deprivation (4)

Answer 30

Cells round up
Decrease in cell no.
Progressive disruption of collagen architecture
Apoptosis

Question 31

Increase in mechanical load

Answer 31

Increase transcription and translation of collagen.

Decrease in mmp-1

Question 32

Cerebral palsy

Answer 32

In cerebral palsy -> lengthening of tendon

Question 33

Overuse of tendon

Answer 33

Increase in bv, rounded cells, lipid degeneration (accumulation of adipose tissue)

Question 34

Low conc of mgcl2

Answer 34

Stain all pg and gags.

Relate activity of nucleus to mechanical load

Question 35

Highest level of mmp?

Answer 35

No strain

Question 36

Under stress deprivation?

Answer 36

Decrease chance of damage to tendon

Question 37

Tenocyte ecm - cross link - actin cytoskeleton

Answer 37

• Interconnects ecm and neighbouring cells - mechanical coupling - info transported by integrins.
• Mod of gene expression
• imp for mechano transduction

Question 38

Aged teno cytes

Answer 38

Not maintain good homeostasis.

Some cells - cytoskeleton depolymerises

Question 39

Tenocyte primary cilium

Answer 39

Single cilium. Deformaion + bending -> cell response (3)
High mech loading - decrease on size.
Low mech loading - increase in size

Question 40

Tenocytes - cilium - cell response (3)

Answer 40

Ca release
Activation of genes
Signalling molecules active