Which Parts of the Brain Regulate the ANS (Autonomic Nervous System)?
The action of the ANS is orchestrated by the spinal cord, brainstem (made up of the midbrain, pons, medulla), hypothalamus, and cerebral cortex.
regulates heartbeat, blood pressure, respiration, and swallowing. All are unconscious activities which are essential to basic survival.
is the messenger pathway, passing messages to and from the brain. It is also our principal reflex hub.
is the brain's "Field Marshall" enabling us to recollect, perceive, communicate, comprehend, and commence voluntary action.(2) All these functions are incidental to conscious behavior.
activates the ANS. In following posts I will show some researched methods which allow us to indeed tweak the behavior of the ANS. First we must go yet still in more detail by considering the automatic and preconscious functions of the ANS.
The ANS is divided in two parts influencing the same organs, with contradictionary effects. These two systems are the sympathetic and parasympathetic.
The sympathetic division prepares the body for stressful situations which require energy expenditure by increasing heartbeat, breathing in order to be able to react to stressful situations such as fear, exercise, rage and so forth.
The parasympathetic division is active in non-stressful, normal situations. This is also the division which allows us to restore the body to a restful state after exposure to stress, hence equalizing the ramifications of the sympathetic division.
To repeat again the ANS controls the SAM axis. The tissues and organs of the ANS are densely fortified with nerve fibers that sustain immune cell population, a great number of them being mobile cells. The motor neurons in these nerve fibers have receptors for neurotransmitters, chemicals of the brain, used to relay messages throughout the body. Cell traffic into these organs takes place in areas that are supplied with a large variety of nerves using several different neurotransmitters. Some of these neurotransmitters include:
When these chemical couriers are unleashed from the nerves, they institute or adjust actions of the lymphocytes, macrophages, and granulocytes a.k.a. immune cells. This process is possible because, even though the nervous system and immune system function in different ways, they have to apportion common receptors for neurotransmitters and neuropeptides. Receptors should be envisioned as docking sites for neurotransmitters and neuropeptides. When they dock, cellular responses are activated or altered as illustrated below.
Immune cells are similar to neurons in that they have receptors to which neurotransmitters and neuropeptides can attach. It is important to know that once neurotransmitters are engaged to immune cells they can affect the immune cells' ability to multiply, travel, or kill invaders. Because these chemicals are released during times of strong emotion, it follows that emotions may modify our susceptibility to disease.
By now it is becoming pretty obvious that the complexity of the human body is such as we need to approach disease and illness by not only focusing on treating the symptoms but also addressing the underlying causes of disease. Allopathic medicine is really good at the first but lacks significantly in the second aspect.
My next post will focus on the indirect pathway, the Hypothalamic-Pituitary-Adrenal Axis:
2. Marieb E. Human Anatomy and Physiology. ed 3. New York. (1995). Benjamin/ Cummings