Post on 29-May-2015
description
THE THE MUSCULOSKELETALMUSCULOSKELETAL SYSTEMSYSTEM
THE THE MUSCULOSKELETALMUSCULOSKELETAL SYSTEMSYSTEM
Bones, joints and musclesBones, joints and musclesTendons, ligaments and Tendons, ligaments and
cartilagecartilage
The human skeleton
• Contains 206 bones
•Initially: flexible cartilage
•Ossification
Process of ossification
• Approximately 20 years
• Growth plates
• Bone building: - Osteoblasts- Osteocytes- Osteoclasts
• Video http://health.howstuffworks.com/adam-200125.htm
Structure of bones
Compact bone
• Outside part of the bone• Extremely strong and hard• Periosteum
Spongy bone
• Mesh-like network (trabeculae)• Red marrow (blood cells)• Yellow marrow (fat)
http://youtu.be/yFJ4iswRiu4
Micrographs
Anatomical classification of bones
• Bones are characterized anatomically as:
– long bones (e.g. humerus, femur)
– flat bones (membrane bones)
– irregular bones (such as the vertebrae)
• All these bone types, regardless of their anatomical form, are composed of both spongy and compact bone.
Functions of the skeleton
• Bone provides the internal support of the body and provides sites of attachment of tendons and muscles, essential for locomotion.
• Bone provides protection for the vital organs of the body: the skull protects the brain; the ribs protect the heart and lungs.
• The hematopoietic bone marrow is protected by the surrounding bony tissue.
• The main store of calcium and phosphate is in bone. Bone has several metabolic functions especially in calcium homeostasis.
• http://youtu.be/8d-RBe8JBVs
• Meeting of two bones
• Make the skeleton flexible
• Types:
- Immovable or fibrous
- Partially movable, or cartilaginous - Freely movable, or synovial
Joints
Joints
• Types of synovial joints:
- Hinge: knees and elbows
- Gliding: wrists and ankles
- Ball and socket: hips and
shoulders
- Pivot: Head
•Cartilage: the bones are covered with cartilage (a connective tissue), which is made up of cells and fibers and is wear-resistant. Cartilage helps reduce the friction of movement.
•Synovial membrane: a tissue that lines the joint and seals it into a joint capsule. The synovial membrane secretes synovial fluid (a clear, sticky fluid) around the joint to lubricate it.
•Ligaments: strong ligaments (tough, elastic bands of connective tissue) surround the joint to give support and limit the joint's movement.
Joints consist of the following:
Joints consist of the following (II)
• Tendons: tendons (another type of tough connective tissue) on each side of a joint attach to muscles that control movement of the joint.
• Bursas: fluid-filled sacs, between bones, ligaments, or other adjacent structures help cushion the friction in a joint.
• Synovial fluid: a clear, sticky fluid secreted by the synovial membrane.
• Meniscus: a curved part of cartilage in the knees and other joints.
Synovial joints
The Muscles
• Pull on the joints, allowing us to move.
• Help the body perform other functions.
• More than 650 muscles ( half of a person's body weight)
• Tendons: tough, cord-like tissues
• 3 different kinds of muscle
How do muscles move?• Contracting and relaxing.
• Work in pairs of flexors and extensors.
• The flexor contracts to bend a limb at a joint.
• The extensor contracts to extend or straighten the limb at the same joint.
How do skeletal muscles work?
http://youtu.be/XoP1diaXVCI