3: Joint Structure and Function Flashcards
define a synarthrosis joint
- essentially no movement
- functions to bind and transfer forces b/w bones
- reinforced by a combo of cartilaginous and connective tissues
define a diarthrosis (synovial) joint
- allows moderate to extensive motion
- synovial fluid-filled cavity
what are 2 types of synarthroses?
- fibrous joints
- cartilaginous joints
what are some examples of fibrous joints?
- sutures of the skull
- distal tibiofibular joint (syndesmosis)
- radioulnar interosseous membrane
what are some examples of cartilaginous joints?
- pubic symphysis
- interbody joint of spine
- manubriosternal joint (in the young)
what are some examples of diarthroses (synovial joints)?
- GH joint
- apophyseal (facet) joints of the spine
- knee
- ankle
what elements are always associated with synovial joints?
- synovial fluid
- articular cartilage
- joint capsule
- synovial membrane
- ligaments
- blood vessels
- sensory nerves
what elements are sometimes associated with synovial joints?
- intra-articular discs or menisci
- peripheral labrum
- fat pads
- bursa
- synovial plicae (overlapped pleats of tissue)
describe the articular capsule of a synovial joint
- composed of CT that encloses the joint
- fibrous layer
- synovial layer or membrane
describe the synovial membrane of a synovial joint
internal layer of articular capsule
describe synovial fluid
- produced by cells within synovial membrane
- coats surfaces of joints, decreases friction, and provides nourishment
what is the function of synovial joint ligaments?
protect from excessive movement
intra-articular discs increase ____ and improve ____
- congruency
- force dispersion
describe the peripheral labrum of a synovial joint
- deepens concave joint
- supports attachment of joint capsule
describe the fat pads of a synovial joint
- reinforce internal aspects of capsule
- fill non-articulating joint spaces
describe the bursa of a synovial joint
- extension of synovial membrane
- filled with synovial fluid
- absorb force
- protect periarticular connective tissue
what are the 3 main functions of synovial joints?
- allow for motion
- bear body weight
- provide stability
what 5 things does connective tissue form?
- capsules
- ligaments
- tendons
- articular cartilage
- fibrocartilage
connective tissue components
- fibrous proteins
- ground substance
- cells
fibrous proteins
- collagen (type I and II)
- elastin
ground substance
- glycosaminoglycans (GAGs)
- water
- solutes
cells
- fibroblasts
- chondrocytes
types of periarticular connective tissue
- dense CT
- articular cartilage
- fibrocartilage
dense CT includes…
- ligaments
- fibrous layer of joint capsule
- tendons
dense CT has a limited ____
blood supply
primary function of dense CT
resist tension
ligaments and joint capsules ____ and ____ the joint
protect and bind
tendons transfer forces between ____ and ____
muscle and bone
describe irregular dense CT
- irregular and haphazard orientation of collagen within ground substance
- suited to resist tensile force in multiple directions
- ex: joint capsule
describe regular dense CT
- more orderly
- nearly parallel orientation of collagen fibers
collagen fibers function most effectively when stretched parallel to _____
- long axis of ligament
- ex: ligaments and tendons
in tendons, the arrangement of collagen fibers is suited to…
high directional tensile loads
in ligaments, the arrangement of collagen fibers is suited to….
variable load direction
hyaline cartilage
- articular cartilage
- distributes and absorbs joint forces and reduces joint friction
- varies in thickness (1-4mm in low compression, 5-7mm in high compression)
- classified as avascular and aneural
- receives nutrition with compression
fibrocartilage
- mixture of dense and articular cartilage
- includes mensici, labrum, discs
- aneural
- limited blood supply (outer rims of some fibrocartilage do have direct blood supply)
primary functions of fibrocartilage
- supports and mechanically stabilizes joints
- dissipates loads across multiple planes
- guides complex arthrokinematics
bone consists of…
- type I collagen
- osteoblasts
- hard ground substance
primary function of bone
- rigid support to body
- systems of levers for muscles
bone can accept tremendous ____ loads
compressive
bone is richly ____ and ____
vascularized and innervated
compact bone
outer cortex of long bones
cancellous bone
end of long bones w thinner layer of compact bone surrounded by a network of cancellous bone
wolff’s law
bone is laid down in areas of high stress and reabsorbed in areas of low stress
define anisotropic
cortical bone responds differently depending on the direction of the force applied
an immobilized joint will demonstrate changes in ____ and ____ of connective tissues if immobilized for prolonged time
structure and function
rate of decline of CT is dependent on ____ of the tissue
metabolic activity
rapid loss of ____ occurs with prolonged reduced loading and recovery is ____
- strength
- slower
