Structure and Function Joints Structure and Function

Joints Joint = Site where any two bones bones meet Some joints don’t move (Immovable) Fibrous Joints Cartilaginous Joints Most joints provide movement (Movable) Synovial Joints

Joint Types – Immovable Fibrous Joints Skull Tibia/fibula Cartilaginous Joints Ribs/sternum Intervertebral discs Fibrous Cartilaginous

Joint Types - Moveable Synovial Joints Structure Includes: Most joints in body Move freely because of lubricating secretion (synovial fluid) Each sub-type has specific movement Structure Includes: Articular cartilage Ligaments Joint capsule lined with synovial membrane Synovial fluid

Joint types – Moveable/synovial Each type has a specific movement Ball and Socket* Hinge* Condylar Plane Pivot Saddle *we will look closely at these two types

Joints – Macroscopic Structure Knee = Hinge Joint

Joints– microscopic structure + Tissues Macroscopic Joint Structure Tissue Type Bone Compact Spongy Articular Cartilage (end of bone) Hyaline Cartilage Meniscus Cartilage (between bones) Fibrocartilage Ligament(bone to bone) Dense (regular) connective Tendon (bone to muscle)

Joints – Microscopic Structure + Tissues Joints are primarily composed of connective tissue Connective Tissue Non- Fibrous Bone Compact Spongy Adipose Cartilage Hyaline Elastic Fibro Fluid Blood Fibrous Dense Regular Irregular Loose

Joint Structure – Cartilage Cartilage – 3 types Hyaline cartilage Fibrocartilage Elastic cartilage Functions Smooth movement Absorbs force Flexibility Support

Joint Structure - meniscus Fibrocartilage Structure Cells and matrix similar to hyaline cartilage Addition of collagen fibers to matrix Found in menisci and vertebral discs Fibrocartilage Function Strength to provides support and flexibility to absorb force Fibrous matrix provides strength Cartilage matrix provides flexibility

Joint structure - ligaments Dense regular connective tissue (same as tendons) Fibers oriented in same direction for strength Function Connects bone to bone Provides stability and proper movement Prevents instability and improper movement Dense regular connective

Joint structure - Tendons Dense regular connective tissue (same as ligaments) Fibers oriented in same direction for strength Function Connects bone to muscle Pulls on bone when muscle contracts Produces movement Dense regular connective