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Week 2 – Bone Structure & Classification
• Although bones appear lifeless, they are alive, and like any other cell in the body, they require food and oxygen to live.
• Water actually makes up 1/3 of a bone’s total mass.
• The rest of the bone is made up of minerals, such as calcium and phosphorus, as well as a protein called collagen.
• The minerals provide hardness for the bones, while the protein gives the bone strength.
Structure continued…
• This means that if the bone was low in minerals it would be very soft and bend easily.
• If they were low in protein then the bones would just snap under any pressure.
• Bone is a very strong structure but is quite light.
• This works out well because the muscles are not equipped to support heavy skeletons.
Types of Bones (Classification)
• There are five different types of bones in the body.
• Each name gives you an indication of what that bone may look like.
• The five different types of bones are long, short, flat, irregular bones and sesamoid.
Long Bones
• Long bones are hard, dense bones.• They provide strength, structure and mobility.• A long bone has a shaft and two ends.• Long bones contain yellow bone marrow and
red bone marrow, which produced red blood cells.
• Examples of long bones include; the femur, humerus and radius.
Short Bones
• In humans, are cubelike in shape.• The length, width and height measurements
are all about the same.• Short bones include; the carpals and tarsals.
Flat Bones
• Made up of a layer of spongy bones between two thin layers of compact bones.
• Their shape is flattened, not rounded.• Flat bones have marrow, but not a bone
marrow cavity.• They protect vital organs or are attachments
sites for large muscles.• Examples of flat bones include; the skull and
ribs.
Irregular Bones
• Have a non-uniform shape.• As such, they do not fall into any other
category.• They consist of cancellous bone, with a thin
layer of compact bone.• Examples of irregular bones include the facial
bones and vertebrae.
Sesamoid Bones
• Is a bone embedded within a tendon.• They are found where tendons pass over a
joint.• This bone causes the tendon to be situated
further away from the joint and as such increases the movement arm.
• They also prevent the tendon from flattening into the joint as tension increases.
Specific Bone Function…
• Skull:– The skull is designed to protect the brain from
injury and shape the face.– There are 29 bones that make up the skull.
Specific Bone Function cont…
• Spine– The spine is responsible for protecting the spinal
cord from injury.– The spinal cords is made up of 36 different bones.
Specific Bone Function cont…
• Ribs– These also serve a protective purpose, these
bones protect the lungs from damage.– They attach to the vertebral column at the back
and the sternum at the front.
Week 3 – Classification of Joints & Anatomical Terms
• There are three different types of joints.• They are called:– Cartilaginous Joints– Fibrous Joints and– Synovial Joints
The joints are classified based on their degree of movement.
Fibrous Joints
• Occur where bones are united.• There is no movement.• For example: the skull and pelvis
Cartilaginous Joints
• Occur where bones are united by intervening cartilage.
• They have limited movement.• For example: the ribs or the vertebrae.
Synovial Joints• Freely moveable joints.• Are directly involved in producing skilled
movement.• For example: knee and shoulder.
Characteristics of a Synovial Joint
• Free movement in at least one direction.• Has cartilage that aids in protection and
cushioning.• Have ligaments that secure bone in place and
allow increased range of movement.• Enclosed by a joint capsule (a synovial
membrane that secretes synovial fluid which promotes lubricated movement).
Hinge Joint
• Has only one axis and allows only flexion and extension.
• Examples: elbow, knee, fingers and toes.
Anatomical Terms• Flexion: joint angle is decreased.• Extension: joint angle is increased.• Abduction: movement away from the midline of the body.• Adduction: movement towards the midline of the body.• Pronation: rotation of the wrist inwards, so palm is facing
down.• Supination: rotations of the wrist outwards, so the palm is
facing down.• Medial rotation: rotation towards the middle of the body.• Lateral rotation: rotation away from the midline.• Inversion: rotation of the foot inwards. Sole is faced outwards.• Eversion: rotation of the foot outwards. Sole is faced inwards.
Skeletal System Questions…
1. List some structures of the skeletal system.2. What are ‘connective tissues’? 3. What is the difference between ligaments, tendons
and cartilage?4. What are the name of the minerals stored in the bone?5. List the functions of the skeletal system.6. What are the biggest and smallest bones in the body?7. Which bones are important for protecting vital organs?
Skeletal System Answers1. The skeletal system is made up of 206 bones. Some of the main structures are
the skull, ribs, femur, humerus etc2. Connective tissues are the ligaments, tendons and cartilages. They are involved
in connecting the system.3. Ligaments: Connect bone to bone and stabilise joint.
Tendons: Connect muscle to bone so the body can move.Cartilage: Surround the end of the bone to prevent grinding.
4. The minerals that are in a bone are calcium and phosphorus for hardness.5. The functions of the skeletal system include:
- Protection- Support- Movement- Production & Storage6. The biggest bone in the body is the femur and the smallest is the stirrup.7. Cranium: Brain Sternum/Ribs: Heart Ribs: Lungs