Why Zebras Don't Get Ulcers: A Guide to Stress, Stress Related Diseases, and Coping

Analgesia refers to an inability to sense pain. Analgesia occurs through a rise in opioid or opiate chemicals. It can occur as a natural phenomenon, such as when a wounded soldier does not feel their injury or, more commonly, when someone runs long enough to experience a “runner’s high.” Analgesia can also arise from artificial circumstances, such as through opiate medications or acupuncture, which trigger a release of natural opioids. Hyperalgesia occurs when the emotional perception of pain is intensified, such as when a person with a fear of needles is hypersensitive to vaccinations.

Anxiety disorders are a group of mental health disorders associated with fear, vigilance, and insecurity. Subtypes of anxiety include generalized anxiety disorder, phobias, obsessive-compulsive disorder, and post-traumatic stress disorder. Symptoms of anxiety may include panic attacks, hyperventilation, ritualized behavior, and vigilance.

CRH is a type of hormone released by the brain in response to stress. CRH, in turn, prompts the pituitary gland to release ACTH, another type of hormone, which then prompts the adrenal gland to release glucocorticoids.

Dysphoria and anhedonia are interchangeable terms for the inability for one to feel pleasure. The inability to feel pleasure is a prominent symptom of major depression.

Epinephrine and Norepinephrine are hormones released by the sympathetic nervous system in response to a stimulus. These hormones prepare the body for intense physical action, such as sprinting.

Fetal Origins of Adult Disease, or FOAD, refers to prenatal conditions that are correlated with adverse adult health. FOAD conditions can be physiological, such as a lack of proper maternal nutrition, or they can be psychological, such as when a fetus’s mother experiences psychological or social stressors.

Glucocorticoids are a group of steroid hormones that are released by the adrenal glands in response to stress. They have similar arousing effects as epinephrine but are slower and longer-acting.

Implicit memories deal with the process of doing things, sometimes without conscious effort, such as what occurs with riding a bicycle. Explicit memories are those concerning factual information, such as recognizing the day of the week. Some information can switch between explicit and implicit memory, such as what occurs when learning to play an instrument, which first requires memorization of techniques and notes but, with practice, becomes automatic. Implicit memory can also become explicit when one focuses on how they perform certain tasks.

Memories can be short-term, meaning they are stored for a relatively short amount of time. Attempting to remember a phone number seen shortly before dialing the number involves short-term memory. Long-term memories are those stored for longer periods of time, and a separate category called remote memory refers to memories made during childhood.

A major depression is a severe depressive episode that lasts for two weeks or longer. Symptoms of major depression include loss of pleasure, lethargy, and thoughts of or attempts at self-harm. Symptoms often affect one’s daily life, resulting in potential job loss or social isolation. Subtypes of major depression include unipolar depression, bipolar or manic depression, and seasonal affective disorders. Depressive episodes often occur in cycles.

Opioids are naturally-occurring chemicals in the body that induce analgesia. Opioid chemicals include endorphins, dynorphins, and enkephalins. Opiates are synthetic chemicals that induce analgesia. Common opiates include heroin, morphine, and opium.

Psychoneuroimmunology is a discipline that examines the link between psychology, neurology, and immunology. Psychoneuroimmunology emerged in the 20th century, although connections between the various systems had been demonstrated before the emergence of the scientific branch.

The autonomic nervous system, which is largely involuntary, is divided into the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is triggered in response to stimulating events, such as stress or excitement, while the parasympathetic nervous system moderates calm functions. The two systems have opposing effects: Where the sympathetic nervous system causes increases in heart rate, breathing, and blood pressure, the parasympathetic nervous system produces a decline in these factors.

Ulcers are sores or holes that can occur in the lining of various organ tissues. Peptic ulcers appear in and around the stomach; they are further divided into duodenal ulcers in the tissue between the stomach and small intestines, esophageal ulcers in the area between the stomach and the esophagus, and gastric ulcers, which occur in the stomach.