A&P Chap 8-9 Flashcards
Joints are also called ________?
Articulations
What are the functions of joints?
- Give skeleton mobility
- Hold skeleton together
What are two classifications of joints?
- Structural: based on what material binds the joints and whether a cavity is present
- Functional: based on movement joint allows
What are three types of structural categories of joints?
- Fibrous
- Cartilaginous
- Synovial
What are three types of functional categories of joints?
- Synarthroses: immovable (e.g. axial skeleton)
- Amphiarthroses: slightly movable (e.g. axial skeleton)
- Diarthroses: freely movable (e.g. appendicular skeleton)
What are the characteristics of fibrous joints?
What are the three types?
- Bones joined by dense fibrous connective tissue
- No joint cavity
- Most are immovable depending on the length of connective tissue fibers
- Sutures
- Syndesmoses
- Gomphoses
What are the characteristics of sutures?
- Rigid, interlocking joints of skull
- Allow for growth during youth (short connective tissue fibers allow expansion)
- Ossify and fuse in middle age
- Immovable joints join skull into one unit
- Closes, immovable sutures are called synostoses
What are the characteristics of syndesmoses?
- Bones connected by ligaments, bands of fibrous tissue
- Fiber length varies, and movement varies
- Short fiber = little to no movement
- Longer fibers = larger amount of movement
What are the characteristics of gomphoses?
- Peg in socket joint
- Teeth in alveolar sockets
- Fibrous connection is the periodontal ligament
- Holds tooth in socket
What are the characteristics of cartilaginous joints?
What are the two types?
- Bones united by cartilage
- Lack a joint cavity
- Not highly movable
- Synchondroses
- Symphyses
What are the characteristics of the synchondroses joint?
- Bar or plate of hyaline cartilage unites bones
- Almost all are synarthrotic (immovable)
- E.g. temporary epiphyseal plate joints (becomes synostoses after plate closure), cartilage of 1st rib with manubrium of sternum
What are the characteristics of the symphyses joint?
- Fibrocartilage unites bone in symphysis joint
- Hyaline cartilage also present as articular cartilage on bony surfaces
- Strong, amphiarthrotic joints
- E.g. intervertebral joints, pubic symphysis
What are the characteristics of the synovial joint?
- Bones separated by fluid filled joint cavity
- All are diarthrotic (freely movable)
- Include almost all limb joints
- Have six general features and classified into six types
- Have bursae and tendon sheaths
- Stability is influenced by 3 factors
- Allow several types of movements
What are the six general features of synovial joints?
- Articular cartilage: consist of hyaline cartilage covering both ends; prevents crushing
- Joint cavity: small, fluid filled potential space
- Articular capsule: two layers thick; external fibrous layer (dense irregular) and inner synovial membrane (loose connective)
- Synovial fluid: viscous, slippery filtrate of plasma and hyaluronic acid; lubricates and nourishes; contains phagocytic cells to remove microbes and debris
- Different types of reinforcing ligaments:
- Capsular: thickened part of fibrous layer
- Extracapsular: outside the capsule
- Intracapsular: deep to capsule, covered in synovial membrane - Nerves and blood vessels: nerve detect pain, monitor joint position and stretch. Capillary beds supply blood filtrate for synovial fluid
Others:
- Fatty pads: cushion between fibrous layer of capsule and synovial membrane or bone
- Articular discs (menisci): fibrocartilage separates articular surface to improve fit of bone ends, stabilize joint and reduce wear and tear
What do bursae and tendon sheaths do?
- Bursae: fuid-filled sac; reduce friction where ligament rub against a bone
- Tendon sheath: elongated bursa; wraps around a tendon
