Are you familiar with the fight or flight response? You will have experienced it many times in your life: when you get a fright, running late or jumping out of a plane! This feeling is important, one that has enabled the survival in all animals including humans.
We are constantly learning more about the complexity of the human body, and a new study published in the journal of Cell Metabolism by Berger et al., has identified the mechanism by which the skeleton becomes essential in the rapid response to fear.
In essence, the animal senses fear triggering the amygdala, often referred to as the fear centre of the brain. The amygdala produces glutamate which signals the skeleton to release a molecule called osteocalcin to be released from the bone within minutes of a stressful event.
This osteocalcin molecule results in the inhibition of the parasympathetic pathway, resulting in increased sympathetic tone – enabling an increase in temperature and energy expenditure, higher heart rate, faster respiration– all necessary for a quick reaction to survive. This response happens at a much faster rate than the glucocorticoid pathway, involving the production of adrenaline which largely takes hours to regulate the physiological processes. In fact this study found that osteocalcin allows the flight or fight response to occur even in adrenal-insufficient patients who can’t produce adrenaline.
In summary, this study found evidence that the skeleton acts as an endocrine organ in that it produces molecules that act of other cells.
Why is this important? As Osteopaths, we consider the body and all of its systems to be part of a whole, rather than just muscles and tendons moving about on bony scaffolding. This study highlights the complexities of the skeleton and deepens our appreciation for how our anatomy interplays with our physiology.
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This post was written by Dr Jess Davies.
You can find out more about Jess here or book an appointment with her here.
Alternatively, you can call the clinic on 9908 2844.
References
“Mediation of the acute stress response by the skeleton,” Cell Metabolism (2019).
DOI: 10.1016/j.cmet.2019.08.012 , https://www.cell.com/cell-metabolism/fulltext/S1550-4131(19)30441-3