Chemistry Ch 7-8

joints

-site where 2 bones meet

structural classification

-material holding bones together (fibrous, cartilaginous, synovial)

functional classification

-based on art of movement allowed

synarthrosis

-no movement

amphiarthrosis

-slight movement

diarthrosis

-freely moveable

fibrous joints

-2 bones joined by fibrous connective tissue w/ no joint activity

-most are immovable

sutures

-interlocking functions filled w/ connective tissue fibers (bones of skull)

syndesmoses

-bones connected by a ligament (connection btw tibia & fibula)

gomphoses

-a “peg-in-socket” joint (tooth in alveolar socket)

cartilaginous joint

-articulating bones united by cartilage & lack joint activity

synchondroses

-united by bar or plate of hyaline cartilage

-all are synarthrotic (epiphyseal plate in children, joint btw 1st ribs & sternum)

symphyses

-hyaline cartilage covers bone but is fused to pas of fibrocartilage; amphiarthrotic

-in vertebral joints, public symphysis

synovial joints

-bones are separated by fluid-containing cavity

-all are freely moveable diathroses

articular cartilage

-hyaline cartilage covering bone ends to ruduce friction

joint (synovial) cavity

-space w/ synovial fluid

articular capsule

-2 layer enclosure

-outer fibrous capsule is continuous w/ the periosteum

-inner synovial membrane covers the internal joint surfaces

synovial fluid

-reduces friction

-circulates nourishment to chondrocytes

Reinforcing ligaments

-strengthens joints

bursae/tendon sheaths

-reducing friction with “bags of lubricant” containing synovial fluid

articular surfaces

-stability increases the better the bone fits together

ligaments

-unite bones

-prevents undesirable motion

-more ligaments=more stable joints

muscle tone

-keeps tendons tight

-provides stability

non axial

-slipping movements

uniaxial

movementiaxialb in 1 plane

biaxial

movements in 2 planes

multiaxial

movements in/around all 3 planes

gliding

-flat surfaces slip over each other

angular movements

-flexion (decreasing angle)

-extension (increasing angle)

-hyperextension (bending backwards)

Abduction/adduction

-movement away or toward the midline

circumduction

-cone in space

rotation

-turning bone around its own axis (hip, shoulder)

supination & pronation

-parallel vs. crossed radius/ulna (forearm0

dorsiflexion & plantar flexion

-pulling toes vs. pointing toes (foot)

inversion & eversion

-turning sole medially vs. laterally (foot)

protraction & retraction

pushing out vs. pulling in (jaw)

elevation & depression

-raising vs. lowering a part (shoulders & jaw)

opposition

-touching thumb to fingers (hands)

plane

-flat surfaces, non axial gliding (inter carpal joints)

hinge

-cylindrical projection in trough, uniaxial (elbow, knee)

pivot

-rounded end in “sleeve”, uniaxial rotation (atlas, dens)

condyloid

-oval surface in oval depression, biaxial (knuckles, wrists)

saddle

-both surfaces have concave & convex areas, biaxial (thumb, carpametacarpal joints)

ball & socket

-spherical head in cup-like surface, multiracial (shoulder, hip)

arhtritis

-100 types of inflammatory or degenerative diseases that damage joints

osteoarthritis (OA)

-”wear & tear”

-caused by aging

-cartilage destroyed faster than replaced

-leads to bone spurs

rheumatoid arthritis (RA)

-autoimmune disease

-immune system attacks joints

-synovial membrane thickens into pannus that erodes cartilage

Gouty arthritis

-caused by deposition of uric-acid crystals in joints

-often at base of great toe