A PPT presentation about the musculoskeletal system that I have prepared for my students of 3rd of ESO

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