Joint Capsule, Synovium, Movement & Innervation Flashcards
The joint capsule is a ____ layer of tissue
fibrous
What is the quality of vascularization and innervation of the joint capsule?
high
____ blend with the joint capsule
ligaments
(hence, ligamentous sleeve)
The majority of ligament fibers of a joint capsule run in the ____ direction
same
What is the joint capsule comprised of?
closely packed collagen fibers
What is the function of the joint capsule?
- limit stretch
- proprioception
Why would someone experience chronic/repeated ankle sprains?
destroyed joint capsule ligaments -> decreased proprioception
The internal portion of the joint capsule is lined by ____
synovial membrane (synovium)
What parts of a joint are covered by synovium?
all internal joint structures (including fat pad on post. knee) except bare area & articular cartilage
What is the synovial membrane comprised of?
2-3 layers of synoviocytes (type A and B)
What are type A synoviocytes?
macrophages with lysosomal enzymes
What are type B synoviocytes?
fibroblast-like cells
What type of synoviocytes help to clean up joints?
type A
What type of synoviocytes produce synovial fluid components?
type B
What are the components of synovial fluid?
- hyaluronate
- collagens
- fibronectin
- glycoproteins
Synovial tissue is arranged in ____ and ____
villi (folds)
microvilli
What is the consistency of synovial fluid?
thick, viscous, egg-like
What is the function of villi and microvilli of synovium?
^surface area for fluid production and waste resorption
What are the functions of synovium?
- diffusion of nutrients (fluid –> cartilage) & waste products (cartilage –> fluid)
- ingestion of joint debris
- secrete hyaluronate, Ig’s (immune function), lysosomal enzymes, proteoglycans
- lubrication
What components secreted by synovium provide the lubricative function of synovium?
- hyaluronate
- proteoglycans (eg. chondroitin sulfate)
(large, negatively charged, hydrophilic molecules)
What changes to synovium occur due to Rheumatoid arthritis?
- less lubrication
- less lysosomal enzymes = less breakdown of waste –> jt adhesions
- less diffusion of nutrients –> starve & breakdown cartilage
How much synovial fluid is in a joint?
1-4 mL
What happens to the amount of synovial fluid with inflammation?
increases (eg. ACL tear)
Why is synovial fluid non-clotting?
comes from plasma with NO clotting factors (thromboplastin, fibrinogen)
Movement is essential for joint ____ and ____
development
maintenance
Synovium and other vascularized structure require ____ to maintain optimal function
regular activity
What is the effect of moderate exercise on articular cartilage?
decreased fibrillation and chondrocyte necrosis
(strengthens cartilage)
What is the effect of immobilization on articular cartilage?
decreased proteoglycans & ^atrophy
What is arthrogryposis?
multiple congenital joint contractures (fibrosis) resulting in lack of joint mobility in utero
What is the clinical presentation of arthrogryposis?
- abnormal CT (fibrosis) deposited around jts = stiffness
- muscle weakness due to underdeveloped mm & tendons
- flattened & incongruent jt surface
What is Hilton’s law?
every peripheral nerve supplying a muscle sends a branch to the joint moved by the muscle and to the skin overlying the joint
What law explains the superficial sensations felt with pathology?
Hilton’s law
What are the 4 types of nerve endings in a joint?
- encapsulated endings
- Pacinian corpuscles
- golgi tendon organs (GTOs)
- free nerve endings
What type of nerve endings respond to mechanical stimuli such as pressure and stretch?
encapsulated
(eg. ligament/joint capsule proprioception)
What type of nerve endings respond to initiation and cessation of movement (acceleration & deceleration), and are considered dynamic?
Pacinian corpsucles
What type of nerve endings are a stretch receptor responding to tension generated at the musculotendinous junction?
golgi tendon organs
(eg. deep tendon reflex)
What type of nerve endings mediate pain?
free nerve endings
