W3 Lecture 1 6/3 Flashcards
How does the human body move?
Via leverage i.e. we are composed of lever systems that facilitate movement
What is bone?
A living and dynamic tissue that is continually remodelled by the forces that act on the body.
How many bones are in the body? (2 subdivisions?)
206 bones in the body divided into axial skeleton and appendicular skeleton
What are the three mechanical functions of the bone?
Support, protection, anchorage
What is support?
Bones in lower body support trunk.
What is protection?
Vertebrae protect the spinal column.
What is anchorage?
For skeletal muscles and ligaments e.g. via bone projections like tubercles.
What are the bone tissue categories?
Compact bone & spongy bone
What is stress?
Measure of the internal force acting. Compact bone withstands greater stress i.e. withstands larger internal forces
What is strain?
Measure of deformation. Spongy bone can withstand greater strain i.e. has more “give” or ability to bend.
What are the bone types?
Long, irregular, flat & short
Long bones?
The bones that form our limbs (levers)
Key structural elements: Diaphysis/shaft
Forms the long axis of the bone. Constructed of compact bone.
KES: Epiphyses
Ends of long bones. Constructed of spongy bone.
KES: Epiphyseal plate (growth plate)
Site of longitudinal bone growth.
KES: Epiphyseal line
Former site of epiphyseal plate
Bone Remodelling
Replaces 5-10% of our skeleton through bone resorption and deposition.
Bone Resorption
Carried out by osteoclast activity (osteoclast=cell that breaks down bone)
Bone Deposition
Carried out by osteoblast activity (osteoblast=cell that forms bone)
Common fracture types
Comminuted, compression, spiral, depressed, greenstick
Bone fracture treatment
Step 1: Reduction (realignment of bones), S2: Immobilisation
Osteoporosis - homeostatic imbalance
Imbalance between resorption & deposition - bone decenty reduced with age due to imbalance
3 ways a joint can be injured
Cartilage tears, sprains (3 grades), dislocations
Joints/articulations
Where 2 or more bones meet
2 fundamental functions of joints
Mobility, hold bones together
Degree of mobility influenced by?
The joints stability & an individual’s flexibility
Joints are classified as being:
- Immovable joints (fibrous) e.g. skull sutures
- Slightly movable (cartilaginous) e.g. pubic symphysis
- Free movable or synovial joints e.g. hip joint
6 types of synovial joints
Pivot, hinge, saddle, plane, condylar/condyloid, ball & socket
Key elements of synovial joint structure (4)
- Joint cavity - filled with synovial fluid
- Articular cartilage - protects bone ends
- Synovial fluid - reduced friction
- Reinforcing ligaments - add stability
3 factors that impact stability of synovial joints
- shapes of articulating surfaces - greater contact = greater stability
- ligaments - more ligaments=stronger joint BUT if ligaments are primary source of stability the joint isn’t particularly stable
- muscle tone - strength/health of tendons that cross joints
2 common homeostatic imbalances
fractures & osteoporosis
Remodeling is regulated by?
Maintaining adequate calcium levels, ensuring the bone is regularly loaded i.e. exercise
