Introduction
Stress is a feeling created when we respond to some events. It is the body’s natural way of preparing to face a difficult situation with alertness, stamina, power, and focus. The stress provokers are called stressors, which cover a variety of situations.
In addition, stress is caused by negative thoughts that have an effect on a person’s mental and physical well being. Stress is also caused by accumulation of continued stressful situations, especially those situations that a person is unable to control, relentless stress that causes a severe acute response to some traumatic events, and acute stress that causes serious illness.
These traumatic events lead to psychological disturbance and anxiety resulting to stress. The following paragraphs discuss the biological factors involved in stress.
Biological Factors Involved in Stress
Stress is subjective because what may be good to one person may be stressful to the other. For example, when flying, many people have anxieties while others love to fly.
Human beings bodies responds the same way to stressful situations, but those who suffer from stress related diseases like depression are unable to turn their body’s’ responses off.
The body’s’ reaction to stress is meant to enhance flow of both adrenaline and cortisol in the blood. Psychological stress may be caused by events leading to emotional disturbances.
Some of these events include losing a loved one or ending a relationship. As the person thinks about the event, his psyche may cause anxiety that leads to stress. He/she might feel unattractive or lose confidence (Aldwin, 2007).
According to scientists, there is no cause of anxiety, but they also argue that the possible causes of anxiety may be due to heredity, brain chemistry and life experiences (Keil, 2004).
Nevertheless, researchers are still learning more about the causes of anxiety. With advancement in technology, scientists will be able to learn more about the biological and psychological effects that causes anxiety and stress. As they continue to analyze the causes, they will be able to offer efficient cure. According to studies, anxiety disorders can also run in families.
Children whose parents have suffered from anxiety disorder have greater chances of having stress. Neuroscientists from Harvard school have found out that prolonged exposure to stress hormones such as corticotrophin and cortisol in mites have resulted to anxiety that leads to depression (Aldwin, 2007).
How the Body Reacts to Stressors
According to Ron de Kloet, Joels, and Holsboer (2005), the body reacts to stressors by stimulating the nervous system and some of the hormones. The hypothalamus sends a signal to the adrenal glands to discharge more adrenaline and cortisol to the blood.
When such hormones are released, they increase the blood pressure: the blood vessels expand to accommodate the blood, thus preparing the muscle for sudden changes.
Other body organs such as the liver respond to the body’s reaction since it releases the stored glucose in order to give the body more energy. In addition, more sweat is released to cool the body.
All these body changes are meant to make a person to react and be able to deal with the situation. The natural result from the body is what we refer to as stress response. Nevertheless, either the body’s response enables a person to cope with stress or it can also cause problems when a person overreacts.
The Role of Brain in Stress
In addition, the brain is the main organ that plays a major role in the body’s view and reaction to stress. In case there is danger, it sends signals to the spinal cord up to the adrenal glands hence alerting them to release adrenaline.
It increases glucose in the blood, heart rate and blood pressure. The hypothalamus is a small part of the brain that helps connect the body’s endocrine and the nervous system because it contains many bidirectional neural inputs and outputs, which come from or to other parts of the brain.
These links enables the regulation of the hypothalamus and gives it ability to produce more hormones into the blood. During stress reaction, the hypothalamus produces a variety of hormones such as corticotrophin releasing hormone that helps in stimulating the body’s pituitary gland to reduce stress (Keil, 2004).
Likewise, amygdala is a section of the brain’s limbic system located in areas such as hypothalamus and locus coerus. Although its main role is to process emotions, it has also been associated with adjusting stress reaction mechanisms, especially when the body experiences fear and anxiety.
The hippocampus is at the medial temporal lobes in the brain; its role is considered memory formation. There are many links from the hypothalamus from cerebral cortex, which includes hypothalamus and amygdale. It influences enhancement, suppression and generating of stress responses (Davis et al., 2007).
Hippocampus can be greatly damaged in case a person has chronic stress. The locus coeruleus is found at the Pons of the brainstem, which is the main area of synthesis of neurotransmitter norepinephrine that has a big role in the sympathetic nervous system reaction to stress. Locus coeruleus receives input from other parts of the brain and protrudes to other parts of the brain to the spinal cord.
The raphe nucleus is at the brain stem. It regulates the body’s moods, especially when stress is brought about by anxiety and depression. The spinal cord’s main role is to transfer stress reaction neural impulses from the brain to the other parts of the body.
The Hypothalamic Pituitary Adrenal (HPA)
HPA is a pathway that transmits information from one part of the body to the other through the chemical messengers. Each pathway receives response in the pathway to hold back the earlier steps.
A biochemical pathway regulates itself through a feedback mechanism. For instance, stress response flow occurs when the hypothalamus gets signals from the limbic system about some of the conditions like energy deficiency that diverge from homeostatic state.
The hypothalamus gets its stimulation from its inputs and then produces corticotrophin hormones. This hormone is then is taken to the pituitary gland, which also secretes its own messenger in form of a hormone to the blood.
When adrocorticotropic hormone gets its target, the adrenal gland, it releases the last messenger – cortisol, which has many effects in the body.
During some situations like a threat, the hypothalamus is notified, and cortisol instructs the body to regain homeostasis by releasing sugar to the heart and brain, but far from the digestive and reproductive system in order to prevent the threat.
When enough cortisol is released to restore homeostasis and the threat is no longer present, the levels of cortisol in the blood flows to the pituitary gland and hypothalamus where it binds and inhibits, thus putting to an end the HPA-axis stress response flow through response inhibition.
Stress and the Immune System
Glavas and Weinberg (2006) affirm that stress affects the immune system particularly when the body’s reaction to stimuli bothers its balance. It also affects cortisol, which is released by adrenal glands.
Cortisol is good in small quantities, but when a person has excessive stress, the level of cortisol rises and slows the production of the prostaglandins that is required. Prostaglandin enhances immune capability and improves the flow of blood.
Many signs of stress correlate with unequal levels of some neuro transmitters. The amount of stress during pregnancy determines the amount of glutocorticoids structure and physiology.
High levels of glutocorticoids as well as some other hormones brought about by anxiety can destroy the limbic system and other parts of the brain that regulate homeostasis.
This affects a person’s mind thus making stress more painful. According to researchers, since stress affect many parts of the body such as the cardiovascular immune and endocrine, then we ought to believe that such stress can cause defects to the unborn baby especially during the early weeks of pregnancy when the fetus body is developing (Davis et al., 2007).
Conclusion
In conclusion, this paper has focused more on biological factors of stress and as discussed, stress is caused by negative thoughts and can have bad effects on an individual’s mental and well being.
It may be psychological or mental. We have also discussed how the body reacts to the stressors, the neuro anatomy and the role of each organ or hormone in the brain, the Hypothalamic Pituitary Adrenal system, the effects of stress on immune system, and effects of stress passed from a pregnant mother to the unborn. Therefore, stress is caused by hormonal responses, internal chemical reactions, and environment changes.
Reference List
Aldwin, C 2007, Stress, coping, and development, 2nd edition, The Guilford Press, New York.
Davis et al. 2007, ‘Prenatal exposure to maternal depression and cortisol influences infant temperament’, Journal of the American Academy of Child & Adolescent Psychiatry, vol. 46, no. 6, p. 737.
Glavas, MM & Weinberg, J 2006, ‘Stress, alcohol consumption, and the hypothalamic-pituitary-adrenal axis’, In Yehuda, S & Mostofsky, DI, Nutrients, stress, and medical disorders, Humana Press, Totowa, NJ, pp. 165–183.
Keil, RMK 2004, ‘Coping and stress: A conceptual analysis, Journal of Advanced Nursing, vol. 45, no. 6, pp. 659–665.
Ron de Kloet, E, Joels, M, & Holsboer, F 2005, ‘Stress and the brain: From adaptation to disease’, Nature Reviews Neuroscience, vol. 6, no. 6, pp. 463–475.