How does stress affect the brain?

We have all read or heard of stress, a natural response which, if given in excess, can affect our health, however, Do we know what happens to our brain when we are under stress?

The WHO defines stress as “the set of physiological reactions which prepare the body for action”. Acute stress that resolves in the short term can be positive because it prepares the brain for better performance. However, constant tension can be fatal. This negative impact of stress occurs when it becomes chronic.

    Stress hormones

    Cortisol is the main stress hormone. When we are faced with a stressful situation, a signal is sent to the pituitary gland which hormonally activates the adrenal glands (small glands located at the top of each kidney). These are the ones that release cortisolAs it rises in the blood, glucose levels rise throughout the body, so organs work more efficiently, being suitable for short periods of time, but not for long periods of time. In addition, there are the following.

    • Glucagon (in a stressful situation the pancreas releases large doses of glucagon into the bloodstream).
    • Prolactin.
    • Sex hormones (such as testosterone and estrogen).
    • The production of progesterone decreases in stressful situations.

    Changes in brain structures caused by stress

    Suffering from chronic stress can cause several reactions in the following areas of our brain:

    1. Seahorse

    One is the death of hippocampal neurons (neurotoxicity). The hippocampus located in the medial part of the temporal lobe of the brain is a structure related to memory and learning, belongs on the one hand to the limbic system and on the other hand to the archicortex, component next to the subiculum and of the dentate gyrus the so-called hippocampal formation. It contains high levels of mineralocorticoid receptors which makes it more vulnerable to long-term biological stress than other areas of the brain.

    Stress-related steroids reduce the activity of certain neurons in the hippocampus, inhibit the genesis of new neurons in the dentate gyrus, and cause dendrite atrophy in pyramidal cells in the CEA3 region. There is evidence of cases in which post-traumatic stress disorder may contribute to hippocampal atrophy. In principle, some effects may be reversible if stress is interrupted, although studies in rats stressed soon after birth for hippocampal function persist throughout life.

      2. Tonsil

      The amygdala is part of the limbic system and is responsible for processing and storing emotional reactions. Recent research suggests that when a person suffers from stress, this area of ​​the brain sends signals to the spinal cord indicating that the production of white blood cells should increase.

      The problem is that too many white blood cells can cause arterial inflammation, which can lead to the development of cardiovascular disease such as stroke, angina, and heart attacks.

        3. Gray and white matter

        Another long-term effect of stress is the imbalance between gray and white matter in the brain.

        Gray matter is made up mostly of cells (neurons that store and process information and support cells called glia) while white matter is made up of axons, which create a network of fibers that interconnect neurons. White matter takes its name from the white sheath, myelin fat surrounding axons and speeds up the flow of electrical signals from one cell to another.

        Chronic stress has been found to generate more myelin-producing cells and fewer neurons than normal. This produces an excess of myelin and therefore white matter in certain areas of the brain, which alters balance and internal communication in the brain.

          mental illness

          Each person is unique and has individual differences in the biological mechanisms of stress, may have a biological basis or be acquired throughout life. They can determine differences in vulnerability or predisposition to develop stress-related disorders.

          In short, stress plays an important role in the onset and course of mental disorders, such as post-traumatic stress disorder, anxiety and depressive disorders, schizophrenic psychosis, and others. It is also an important risk factor and a component in drug addiction and addiction disorders.

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