How Does Stress Affect The Immune System?

814 Words4 Pages
Question Set A:
1. When we experience stress, how is the endocrine system activated? How does it become deactivated?
The stress response involved the HPA-hypothalamic-pituitary-adrenal axis. First, the hypothalamus activates the sympathetic nervous system. The adrenal gland then secretes epinephrine and norepinephrine, which increase heart rate. The pituitary gland produces hormones that tell the adrenal gland to secrete cortisol, which is involved with the release of stored energy. The negative feedback loop comes into effect when the hypothalamus detects that the cortisol has reached a certain concentration, thus returning the body to homeostasis.
2. How does stress directly affect the immune system?
Stress negatively impacts the ability of the immune system to fight infection. Glucocorticoids, which include cortisol in the HPA, inhibit responses of both B and T cells by preventing them from recognizing interleukin (a cytokine subclass) signals. Glucocorticoids also inhibit the expression of fc receptors on macrophages, which impacts their ability to phagocytose pathogens.
3. What is the difference between allostasis and homeostasis?
Allostasis is the process of achieving homeostasis, or internal balance, through behavioral, HPA/hormonal, and other physiological changes. Homeostasis is when the body maintains stability despite environmental stressors or changes, such as a change in temperature.
4. How do ulcers arise?
Stress is not the only factor in the development of
Get Access