The document outlines the structure and functions of the musculoskeletal system, including bones, joints, and muscles. It describes the components of bones, types of joints, and the role of muscles in movement, emphasizing their importance for support, protection, and metabolic functions. Key details include the process of ossification, types of synovial joints, and the relationship between tendons and muscle movement.

1. THE MUSCULOSKELETAL
SYSTEM
Bones, joints and muscles
Tendons, ligaments and cartilage

2. The human skeleton
• Contains 206 bones
•Initially: flexible cartilage
•Ossification

3. Process of ossification
• Approximately 20 years
• Growth plates
• Bone building: - Osteoblasts
- Osteocytes
- Osteoclasts
• Video
http://health.howstuffworks.com/adam-2001
25.htm

4. 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

5. Micrographs

6. 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.

7. 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

8. Joints
• Meeting of two bones
• Make the skeleton flexible
• Types:
- Immovable or fibrous
- Partially movable, or cartilaginous
- Freely movable, or synovial

9. Joints
• Types of synovial joints:
- Hinge: knees and elbows
- Gliding: wrists and ankles
- Ball and socket: hips and
shoulders
- Pivot: Head

10. Joints consist of the following:
•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.

11. 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.

12. Synovial joints

13. 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

14. 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.

15. How do skeletal muscles work?
http://youtu.be/XoP1diaXVCI