Arthrology: Contemporary Classification - Diarthrosis, Common Features Flashcards
What are the synonyms for synovial (diarthrosis) joints?
junctura synovalis or synovial joint
What are the four consistent features of synovial (diarthrosis) joints?
articular or fibrous capsule, synovial membrane, articular cartilage, and synovial fluid
Thickening of the fibrous capsule connective tissue will form the what?
capsular ligament
What generic accessory ligaments may accompany and support the capsular ligament?
intracapsular and extracapsular ligaments
What are examples of intracapsular and extracapsular ligaments?
intracapsular ligaments - cruciate ligaments of the knee; extracapsular ligaments - collateral ligaments of the knee
What is the generic function of ligaments?
stimulate reflex contraction of muscles around the joint
What are the characteristics of the type I articular receptors?
located in the superficial layer of the fibrous capsule, resemble Ruffini endings, most numerous in cervical zygapophyses, and they monitor the joint “at rest”
What are the characteristics of type II articular receptors?
located in deeper strata of the fibrous capsule, resemble Pacinian corpuscles, most numerous in the cervical spine, and monitor the joint during normal range of motion
What are the characteristics of type III articular receptors?
present in collateral and intrinsic ligaments, resemble Golgi tendon organs, not initially observed along the vertebral column, and monitor extreme joint motion
What is the function of type IV articular receptors?
nociceptive, they monitor pain
Type IVa articular receptors would be present in what locations?
fibrous capsule, articular fat pads, or adventitia of blood vessels
Type IVb articular receptors would be present in what location?
accessory ligaments in general, dense in the posterior longitudinal ligament of the spine
Type IV articular receptors would be absent in what part(s) of the synovial (diarthrosis) joint?
synovial membrane, articular cartilage, and synovial menisci or intra-articular discs
What are the three classifications of synovial membrane?
articular, vaginal, and bursal synovial membrane
What are the three modifications of articular synovial membrane?
1) synovial villi, 2) articular fat pads or Haversian glands, 3) synovial menisci and intra-articular discs
What is the generic function of modifications of articular synovial membrane?
aid in spreading synovial fluid
What is the name given to the finger-like extensions of the synovial membrane? What is their apparent function?
synovial villi; increase the surface of synovial membrane available for secretion-absorption phenomena
What role will aging have in synovial villi number?
synovial villi increase with age
What is another name for the articular fat pad? Where are they located?
Haversian gland; in the fibrous layer of synovial membrane; they are absent from articular cartilage, synovial menisci, and intra-articular disc
Articular fat pads are most numerous in what location along the vertebral column?
lumbar zygapophyses
Condensed fibrous connective tissue or fibrocartilage projections of the synovial membrane are called what?
synovial menisci or intra-articular discs
Intra-articular discs are a feature of what joint examples?
temporomandibular, sternoclavicular, acromioclavicular, and radio-ulnar joints
Synovial menisci are a feature of what joint examples?
femur-tibia articulation, cervical zygapophyses and lumbar zygapophyses
What are the layers of the synovial membrane?
outer fibrous layer and an inner (lumenal) cellular layer AKA synovial lamina intima
What are the specific functions of type A synovial cells?
are phagocytic
What are the specific functions of type B synovial cells?
secrete proteinaceous substances and hyaluronic acid
What is the common function of type A and B synovial cells?
formation and absorption of synovial fluid
How does the articular cartilage thickness vary within the joint?
male (convex) surfaces on bone are thicker at the center of the articular region; female (concave) surfaces on bone are thicker at the periphery of the articular region
What is the source of nutrition for articular cartilage?
blood vessels in the synovial membrane, sinuses of the bone marrow cavity, and from synovial fluid itself
What is unique about the surface of articular cartilage?
a true perichondrium is absent
What are the primary constituents of articular cartilage?
water, cells, collagen type II fibers, and a proteoglycan gel
Which collagen fiber type predominates in articular cartilage?
type II
What are proteoglycans composed of?
a core protein and glycosaminoglycans
What are glycosaminoglycans?
relatively long, non-branched carbohydrates formed from repeating units of disaccharides
What are examples of glycosaminoglycans important in articular cartilage?
hyaluronic acid, chondroitin sulfates, and keratin sulfates
What is the architecture of the largest proteoglycans?
a backbone of hyaluronic acid to which core proteins are bound, chondroitin sulfates and keratin sulfates are then bound to the core protein
What is the primary function of bound glycosaminoglycans in articular cartilage?
form a network for water retention
Cartilage is able to change shape due to compression, a characteristic known as what?
deformation
What is implied when cartilage is said to have elastic properties?
cartilage can deform and returns to original volume rapidly, a time independent property
What is implied when cartilage is said to have viscoelastic properties?
cartilage can deform but returns to original volume slowly, a time dependent property
Which theory of joint lubrication implies a loss of fluid from the cartilage into the joint space during compression results in increased viscosity of the synovial fluid?
weeping theory
Which theory of joint lubrication implies water loss from the synovial fluid increases viscosity of the remaining synovial fluid?
boosted theory
Which theory of joint lubrication implies and adsorption of lubricant onto cartilage surfaces is responsible for the low-friction observed during movement?
boundary theory
What are the properties of synovial fluid?
it is yellow-white, viscous, slightly alkaline, and tastes salty
Synovial fluid consists of what specific chemical groups?
fats, salts, albumins, and hyaluronate
Which sustance in synovial fluid was first thought to be responsible for its viscosity and lubricating behavior?
hyaluronate
What substance of synovial fluid has been proposed to be responsible for its viscosity and lubricating behavior?
lubricin
What cells are often observed in synovial fluid?
white blood cells and a few other types of connective tissue cells
What is the function of synovial fluid?
provides a nutritive source for articular cartilage and supply the lubricant for the cartilage surface
