very comfortable in your easy chair. You are lunching while leisurely flipping through the newspaper and listening to the news. And suddenly—bam! bam! bam!—you hear a forceful knock on the door. Before you can ask who it is, a squad of police kicks the door open, and all eyes and guns are pointed at you!
Well, right about now you are not feeling very comfortable! That leisurely, relaxed feeling that you just had seconds ago is all gone, and you are now sweating bullets. But the police are very polite! They say, “We are so sorry. Oops, it’s the wrong house.”
You are grateful to learn it’s a mistake, but your body has encountered major stress and is still going through some serious changes. Their blunder has kicked off a cascade of events right now in your body.
Let’s take a closer look at what happened:
Messages from the outside world are picked up by our senses; this information is transmitted on nerves cells with lightning speed and registered at the relay center (the thalamus). The thalamus sends the information to the limbic system (the emotional part of the brain) and the frontal lobe (the thinking part of the brain); they witness what just happened! The frontal lobe says: “Just relax, take a deep breath, calm down; thank goodness I wasn’t shot!” But the emotional part of the brain is hysterical! It’s shouting and yelling and screaming, “What do you mean, just calm down?! You saw what just happened! Don’t just stand there, do something now!”
This “do something now” sets into motion a series of connections from the brain to the body, along a pathway called the HPA axis. This axis is composed of the hypothalamus, pituitary gland, and adrenal glands (Preston, 2009).
Before we take a look at what messages are being sent and how this relates to the police blunder, as well as to Karen who was emotionally abused, we need to understand the functions of the three parts of this HPA axis. We will then see the connections between our brain, hormones, and immune system.
The hypothalamus is located in the brain and so is the pituitary gland. But the two adrenal glands are quite a distance away—on top of the kidneys. Although they are a distance from the brain, they receive messages within milliseconds.
The hypothalamus has many important roles. It’s the body’s thermostat and controls temperature, thirst, hunger, and sexual drive. It regulates blood pressure, heart rate, digestion of food, sleep cycle, and the immune system—all of which are under the control of the autonomic nervous system (ANS). These functions, as the name implies, are automatic.
Another important role of the hypothalamus is the release of the stress hormone, corticotrophin-releasing hormone (CRH). CRH production and the function of the ANS are the two major players in the hypothalamus that impact physical and mental health.
The pituitary gland is the size of a pea and is located at the base of the brain right under the hypothalamus. In the past the pituitary was called the master gland; however, we now know that the hypothalamus is its master. It tells the pituitary when, where, and how to do its job.
The pituitary gland is a major endocrine system; it directs the release of chemical messengers in the form of hormones. It is the link between the brain and the body. Its hormones are secreted into the blood stream and head for targeted organs, carrying messages as to how and when the body should respond. Some of the hormones controlled by the pituitary gland include: thyroid hormone, prolactin (which stimulates breast milk production), human growth hormone, and ACTH (adrenal gland stimulation).
Without the proper regulation of hormones, the body will malfunction. Case in point is novelist and playwright J. M. Barrie, better known as the creator of the character Peter Pan. His writings have entertained children for many generations. In the book Why Zebras Don’t Get Ulcers, Robert Sapolsky, a Stanford neuroscientist, indicates that this beloved author stopped growing and as an adult stood barely five feet tall. J. M. Barrie had a classic case of stress dwarfism. He experienced several psychological stresses as a child: the death of a brother, a mostly absentee father, and a grieving, depressed mother. As a result of her depression, she ignored her son for many years. This stress produced extremely low levels of circulating growth hormones and led to Barrie’s stunted growth (Sapolsky, 2004). I personally know a young teen whose growth has been stunted, for which there is no medical explanation. He has lived in a chaotic, stressful family environment and, like Barrie, he was found to have extremely low levels of growth hormone.
Another important hormone released by the pituitary gland is adrenocorticotropic hormone (ACTH). When ACTH is released into the blood stream, it is picked up by the adrenal glands—the two glands sitting on top of the kidneys. The adrenals also have many functions, two of which involve the stress response, the release of the fight or flight chemicals (epinephrine, norepinephrine), and the production of cortisol, which—in addition to being a response to stress—also involves the release of blood sugar, suppression of the immune system, and the metabolism of fat, protein, and carbohydrates.
The adrenal glands’ role in the production of cortisol and the stress hormones epinephrine and norepinephrine is important. These are the major players when it comes to the difference between those of us who get sick and those who do not (Kemeny, 2010).
The HPA axis—the hypothalamus, pituitary, and adrenal—forms the mind-body connection. These systems function as feedback centers, continuously monitoring and communicating what is going on in the brain and body and how it should respond.
This axis is critical to survival, releasing controlled levels of hormones in the right doses at the right times and maintaining balance in the body by regulating crucial body functions. However this system can be detrimental to our health when it gets out of balance, being over- or under- stimulated.
We all have experienced over-stimulation of this system. Just think back to the last time you were in traffic, and the driver from Hades appeared out of nowhere. He crossed your path, causing you to perform some fancy maneuvers to avoid hitting him and to dodge the car in the next lane. Unless you are in zombie land, your body did what every human body does. Immediately you went into a fight-flight stress response, an automatic nervous system response triggered by the HPA axis.
You more than likely felt as if your heart was going to jump out of your chest; this is because your heart rate and blood pressure increased. Mentally you were more alert because you needed to think critically, weighing your options in this emergency. At the same time your energy stores were being mobilized, giving you a surge of energy due to increased blood sugar levels. You started breathing faster, your pupils dilated, and you felt shaky and nervous. All this happens extremely fast—within milliseconds!
This is the brain and hormonal chemical response, but what about the immune system? How does it fit into the equation and cause disease?
The Immune System
God made provision for the body to defend itself when invaded by unwelcome guests. These uninvited visitors come in many forms: viruses, bacteria, and parasites to name a few. And the immune system, the defender of the body, is waiting at the door, ready to go to battle.
Similar to a military’s SWAT team, the immune system has special weapons and tactics enlisted to fight the body’s battle. The major players are WBC’s, T-cells, B-cells, Natural Killer Cells, monocytes, and the macrophage (Goodman, 2004). These immune cells are located all over the body and lay in wait to pounce on unsuspecting intruders.
Their response to invaders reminds me of an attempted robbery gone awry. Remember those old funny movies with the clumsy robber dressed in black? He’s wearing a mask, and he’s carrying a sack on his back to collect the loot. He stealthily climbs to his destination and is ready for the steal, but along the way he is bitten, clubbed, stabbed, chased, beaten, and then arrested. This is what the immune system
