Mechanisms of Injury Flashcards
How are injuries classified?
Cause-based or tissue-based
What are the cause-based classifications of injuries?
1) Primary
- Direct/extrinsic
- Indirect/intrinsic
- Overuse
2) Secondary (re-injury)
- Short term
- Long term
What is the cause of a primary direct/extrinsic injury?
External causes, such as a collision with another athlete or piece of equipment
What can primary direct/extrinsic injuries result in?
Fractures, joint dislocation, ligament/muscle injury and skin abrasions
What is a primary indirect/intrinsic injury?
An injury caused by the athlete to themselves, e.g. inadequate warm-up
What is a primary overuse injury?
When apposing structures are in constant contact resulting in frictional wear between the structures e.g. bursitis
What are secondary short term and long term injuries?
Short term: Injury following previous mismanagement
Long term: Injury that leads to degenerative problems e.g. osteoarthritis
What are the tissue-based classifications of injuries?
Soft tissue, hard tissue, special tissue/organ
What is classified as soft tissue?
- Skin
- Musculotendon unit/tenoperiosteal
- Muscle compartments
- Joints (ligaments/tendons)
- Intervertebral discs
What is classified as hard tissue?
- Bone
- Cartilage (hyaline, articulate, epiphyseal)
What is classified as special tissue/organs?
- Brain/nerves
- Eyes/nose/sinus/larynx/teeth
- Thoracic/abdominal/pelvic organs
Describe the characteristics of collagen
- Most abundant protein in the body
- Linear, stable, water insoluble
- Cross-linked fibres
- Withstands high longitudinal stress
What are the 6 forms of collagen based on?
Molecular chain structure, location and function
Where is type 1 and 2 collagen located?
Type 1: Synovium, bone, tendon, skin and eyes
Type 2: Cartilage, eyes
What is the relationship between the collagen type number and the fibre diameter?
As the collagen type number increases, the fibre diameter decreases (e.g. type 1 is the largest)
What type of collagen is used for repair injuries?
Type 3
What are the three phases of general pathology repair?
- Acute inflammation response
- Matrix and cellular proliferation
- Remodelling and maturation
When does the acute inflammation response phase occur and how long does it last?
0-72 hours post injury, can last up to 6 days
How is acute inflammation treated?
RICER
What are the steps of the acute inflammation response phase?
1) Damaged tissues release histamines, increases blood flow to the area
2) Histamines cause capillaries to leak, releasing phagocytes and clotting factors into the area
3) Phagocytes engulf the bacteria, dead cells and cellular debris (phagocytosis)
4) Platelets move out of the capillary to seal the wounded area
What is the effect of aspirin on the healing process?
It delays the healing process
What are the steps of phagocytosis?
1) Microbe adheres to phagocyte
2) Phagocyte forms pseudopods
3) Phagocytic vesicle containing antigen fuses with a lysosome (phagolysosome)
4) Microbe in fused vesicle is killed and digested by lysosomal enzymes
5) Indigestible and residual material is removed by exocytosis
What are the functions of inflammation?
- Destroys injurious agents
- Dilutes toxic chemicals
- Cleans up necrotic waste
- Paves the way for repair
What are the steps of the matrix and cellular proliferation phase?
- Proliferation of capillaries and fibroblasts
- Collagen/proteoglycan matrix production
- Formation of granulation tissue
- Capillary network budding
- Fibroblasts produce type 3 collagen
- Contraction of wound
What is the role of fibronectin in the matrix and cellular proliferation phase?
Acts as an anchoring compound