Musculoskeletal System

Musculoskeletal System

1. Humans have an endoskeleton composed of bone and cartilage

   • Cauliflower ear: ear cartilage breaks down
   • 3 types of cartilage
     • Hyaline cartilage: tracheal rings, end of nose, end of sternum, and in articulating joints
     • Elastic cartilage: external ear
     • Fibrocartilage: found in intervertebral disks

2. Bone structures and functions

   • Bone functions
     • interact with muscles to move the muscles to move the body
     • support and protect
     • depository for calcium and phosphorous
     • blood production
   • Structures
     • composite bone: found on the outside of the bone
     • osteocytes: bone cells found in compact bone and housed in spaces called lacunae
     • Haversian systems: found in compact bone and are composed of concentric circles called lamellae
     • Haversian canal: found at the center of the Haversian system; contains blood vessels and nerves
     • Canaliculi: tiny channels that connect Haversian canals to osteocytes
     • Spongy bones: found mostly in the epiphysis, and contains red marrow that produces blood cells

3. Skeletal joints

   • joints are areas of contact or near-contact between bones
     • 3 types
       • fibrous joints: have no gap between the bones
         • flat cranial bones
       • cartilaginous: permit only slight movement
         • intervertebral disks
       • synovial joints: move freely
         • stabilized by ligaments
           • ligaments connect bones to bones
         • synovial fluid lubricates the joint
         • ball and socket joints, hinge joints have most range of motion
   • vulnerable to strain
     • ligament tearing is sprain
     • damage to muscle or tendon is strain
     • in osteoarthritis, the cartilage at the end of a bone wears out
     • in rheumatoid arthritis, the synovial membranes become inflamed, the cartilage degenerates, and bone is deposited in the joint
   • osteoperosis
     • osteoblast malfunction

4. how muscles and bones interact

   • each skeletal muscle has hundreds of thousands of muscle cells
   • muscles connect to bone near joints, transmit force to bones via tendons
   • skeletal muscles interact (work with and in opposition to one another) to conduct tasks