Injury Response Process Chapter 10

Why do we care about this process? We must have a basic understanding of how the body responds to an injury.

Great Adaption Syndrome (GAS) 1. Alarm Stage 2. Resistance Stage 3. Exhaustion Stage

GAS: Alarm Stage Flight or fight response Body tries to thwart effects of the stressor by readying defense systems Increase blood supply to areas that need it Cortisol is released to regulate inflammation, stimulate cellular activity, and prepare the body to deal with trauma.

GAS: Resistance Stage Longest phase Plateau in body’s adaption to the stress Body continues to adapt to the stressor Body achieves physiological resistance

GAS: Exhaustion Stage When body can no longer withstand the applied stress; failure occurs. Result: traumatic or overuse injuries

GAS: Relationship to Trauma Beneficial vs. Harmful stress Harmful may be… Too much force in a short period of time- macrotrauma Repeated, low intensity forces- microtrauma

GAS: Relationship to Trauma Amount of stress applied to body must be of proper intensity and duration for body to develop physiological resistance To balance + and – stress, body adapts: Wolff’s Law: applying enough stress but not too much Hypertrophy: increase in muscle cell size Remodeling of collagen fibers (scar tissue): apply stresses so will align properly

Definitions: Ischemia: decreased blood supply Hypoxia: lack of oxygen supply Inflammation: tissue reaction to injury Edema: excessive accumulation of fluids Hemorrhage: bleeding

Injury Process: 2 Parts Primary Reaction Secondary Damage Tissue destruction associated with the traumatic force Secondary Damage Cell death caused by blockage of oxygen supply to the injured area Enzymatic damage and mitrochondrial failure

Three Phases to Healing 1. Acute Inflammatory Response 2. Proliferation Phase 3. Maturation (Remodeling) Phase

Acute Inflammatory Response Delivery of phagocytes and fibroblasts into the area Formulation of granulation tissue: isolates the trauma) Histamine released (increase capillary permeablity)- results in redness, heat, swelling

Inflammation Body’s defense mechanism Body’s reaction to cell injury or death Triggered by mechanical trauma (spraining a ligament, bacterial invasion, chemical irritation, or burns)

Do we want inflammation? Essential part of the healing process However, if the duration or intensity of the inflammation is excessive, the process becomes detrimental and chronic inflammation becomes a debilitating event Body overreacts to trauma

Purpose of Inflammation To control the effects of trauma and return the tissue to its normal state Initially… contains, destroys, dilutes injurious agents and localizes damage Pain that follows… alerts the athlete that damage has occurred Muscle guarding: “Splints” the area

Cardinal Signs of Inflammation Heat Redness Swelling Pain Loss of function

Proliferation Phase 72 hours-3 weeks Number/size of fibroblasts increase Ground substance and collagen to collect in injured area (scar tissue) in preparation to rebuild injured area.

Proliferation Phase Revascularization: proteins produce new capillary beds and granulation tissue. Fibroblasts lay down collagen to form seal over injured area and extracellular matrix is developed (mostly water content to reduce friction) Collagen (Type III) is laid down haphazardly; controlled stress caused fibers to arrange themselves more orderly.

Maturation Phrase 3 weeks- 1 year Collagen and fibroblasts align themselves and attempt to adapt to original tissue orientation. Very important to apply controlled stress in this phase to properly align collagen.