Describe the body’s stress response in terms of the actions of the adrenal cortex and medulla. What are the different hormones involved, where are they produced, what type of gland produces them, what type of chemical are they, and how do they contribute to the stress response?
The body's stress response involves the actions of both the adrenal cortex and the adrenal medulla. Let's break it down and understand the role of each component:
1. Adrenal Cortex: The adrenal cortex is responsible for producing several hormones, primarily glucocorticoids, such as cortisol, and mineralocorticoids, such as aldosterone. These hormones are produced in the outer part of the adrenal glands, which are located on top of the kidneys.
- Glucocorticoids (e.g., cortisol): Glucocorticoids are steroid hormones that help regulate metabolism and the immune system. In the stress response, cortisol levels increase to mobilize energy reserves by promoting the breakdown of stored glycogen into glucose. This boosts energy availability to cope with stressors.
- Mineralocorticoids (e.g., aldosterone): Mineralocorticoids regulate electrolyte and fluid balance by controlling the absorption and excretion of sodium and potassium ions. In the stress response, aldosterone assists in maintaining blood pressure and blood volume, which may be necessary during a fight-or-flight situation.
2. Adrenal Medulla: The adrenal medulla is responsible for releasing two hormones: epinephrine (adrenaline) and norepinephrine (noradrenaline). These hormones are part of the sympathetic nervous system's response to stress and are released into the bloodstream.
- Epinephrine: Epinephrine is a catecholamine, a type of neurotransmitter produced in the adrenal medulla. It acts as a stress hormone, rapidly increasing heart rate, dilating air passages, and providing a burst of energy to prepare the body for physical exertion. It enhances the fight-or-flight response by increasing blood flow to the muscles.
- Norepinephrine: Norepinephrine works together with epinephrine to mediate the stress response. It increases heart rate, constricts blood vessels to raise blood pressure, and boosts the availability of glucose for energy.
Together, the adrenal cortex and medulla hormones play crucial roles in the body's stress response by mobilizing energy reserves, increasing heart rate and blood pressure, and redirecting resources to the muscles and organs that are important for immediate survival. These hormone responses help individuals respond effectively to stressful situations.