Stress & Compensation

Question 1

Origins of stress: External vs Internal

Answer 1

External: posture and movement habits, short duration high impact (MVA), long direction low impact

Internal: thoughts, emotions, past experiences

Question 2

3 types of nociceptors:

Answer 2

• Temperature
• Mechanical (pressure, sharp/dull)
• Chemical (from torn tissues, metabolic waste stasis, ischemia, hormones)

Question 3

Dorsal Root Ganglion (DRG)

Answer 3

Dorsal Root Ganglion (DRG) is the first judge of the meaning of the information, either:

• Handling info at spinal cord levels OR
• Relaying potential threat to the brain

Question 4

Factors affecting the brains response:

genetic and non-genetic

Answer 4

Non genetic:

• Past experiences (learning, culture, previous trauma)
• Present perception of injury (sight, sound, smells, perception of threat)
• Internal chemical environment (neural, endocrine, immune system)

Genetic

• Diathesis: the inherent vulnerability of a person under stress to become dysfunctional (they are not a whiner, it’s genetic, they feel more pain)
• Synthesis of proteins affecting plasticity of the nervous system (may be decreased and take longer to get to pre-injury state)
• Variability in nociceptive sensitivity (some people nociceptor fir more easily than others)
• Production and effect of endogenic opiates

Question 5

Systemic responses / compensations

Answer 5

• Protection: immune response/inflammation, thought, movement, pain, endocrine response, autonomic response, chemical
• external motor reaction (take hand off burner)
• cognitive reasoning (how bad is the burn? Do I need to go to the hospital?)
• activation of the autonomic nervous system (sympathetic/parasympathetic)
• endocrine system - fight or flight (adrenaline) OR rest and heal (endorphins, melatonin, PTH – vit D)

Question 6

Local tissues responses

Answer 6

• Blood vessel constriction, coagulation, production of healing factors (sympathetic NS)
• Secondary vasodilation: erythema, edema, heat (inflammation vs immune system)
• Pro-inflammatory cytokine and chemical release (Immune system) to hypersensitize local C-fibers
• C-fibers (located in skin, muscle, bone, CT, viscera, blood vessels) actively release substance P and other peptides to trigger local inflammation
• Activity during healing creates enhances collagen turnover, collagen synthesis, increased collagen cross sectional area, decreased stress susceptibility and load resistance