Skeletal System and Joints (Components of Typical Long Bone (Endosteum-…
Skeletal System and Joints
Types of Synovial Joints
Ball and Socket Joint- Flexion and Extension, Adduction and Abduction, and Rotation. Ex: Shoulder and hip Joints
Saddle Joints- Adduction and Abduction, Flexion and Extension. Ex: carpometacarpal joints of thumbs
Condylar Joint- Flexion and Extension, Adduction and abduction. Ex: Wrist joints
Pivot Joint- Rotation Ex: Atlantoaxial Joint
Hinge Joint- Flexion and Extension Ex: Elbow Joints
Plane Joint- Gliding Ex: Intercarpal and Intertarsal Joints
Structural Components of Synovial Joints
Tendon Sheathe- specialized bursa that wraps around tendons but not completely.
Bursa(e)- fibrous sac filled with synovial fluid
Synovial fluid- lubricates joints and reduces friction and nourishes articular cartilage
Synovial membrane- produce and secrete synovial fluid which fills the joint cavity
Joint Capsule- Outer is Dense Irregular C.T continuous with periosteum. Inner is Areolar C.T which contains the Synovial membrane
Articular Cartilage- Hyaline cartilage
Synovial Joint- most movable joints in body, all freely movable. Each Synovial joint contains fluid filled joint cavity.
Symphysis (Fibrocartilage)- Slightly movable. Ex: Intervertebral Discs
Synchondrosis (Hyaline)- Immobile. Ex: Manubrium of Sternum
Cartilaginous Joints- Bones united by cartilage. No Joint cavity. 2 types
Gomphoses (Peridontal Ligament)- Immobile, peg in socket joint. Articulation of tooth with its socket.
Syndesmoses (Longer fibers)- Slightly mobile, held together by a ligament.
Suture (short fibers)- Immovable, only found in skull, held together by interlocking fibers.
Fibrous Joints- Bones held together by collagenic fibers. No joint cavity. 3 types
Types of Bone Cells
Osteoclasts- formed from leukocytes, secrete enzymes that break down bone tissue.
Osteocytes- Function to keep bone matrix healthy
Osteoblasts- Cells that produce and secrete new extracellular matrix
Osteogenic cells- Produce stem cells that differentiate into osteoblasts
Components of Typical Long Bone
Endosteum- membrane covering internal bone surfaces including trabeculae of spongy bone and lines central canal of osteons.
Periosteum- membrane covering entire outer surface except location of articular cartilage. Contains two layers an outer dense irregular C.T which resists tension and bending and an inner layer that is osteogenic
Medullary Cavity- Center of diaphysis, filled with yellow bone marrow (fat)
Blood Vessels- Supply nutrients through opening in wall of diaphysis
Epiphyses- Forms bone ends
Diaphysis- Forms shaft
Articular Cartilage- (Hyaline), covers end of most bones at movable joints
Spongy Bone- Internal Layer, contain trabeculae filled with bone marrow.
Compact Bone- External Layer
Long Bone- A shaft and two distinct ends