Final answer:
Epinephrine, or adrenaline, is mainly produced by the adrenal medulla, located on top of the kidneys. It is the primary hormone secreted by the adrenal medulla and plays a crucial role in the fight-or-flight response.
Step-by-step explanation:
Epinephrine, also known as adrenaline, is mainly produced by the adrenal medulla. The adrenal medulla is part of the adrenal glands, which are located on top of the kidneys. The adrenal medulla contains two types of secretory cells, one that produces epinephrine and another that produces norepinephrine. Epinephrine is the primary hormone produced by the adrenal medulla, accounting for 75 to 80 percent of its secretions.
To understand where epinephrine is produced, let's take a closer look at the adrenal glands. The adrenal glands are small, triangular-shaped organs located on top of the kidneys. They are divided into two main regions: the outer cortex and the inner medulla. The cortex produces steroid hormones such as cortisol, aldosterone, and sex hormones. On the other hand, the medulla is responsible for producing epinephrine and norepinephrine, which are non-steroid catecholamines.
Epinephrine and norepinephrine are released in response to short-term stress or during the fight-or-flight response. They trigger physiological changes in the body to prepare it for immediate action. These hormones increase heart rate, breathing rate, cardiac muscle contractions, blood pressure, and blood glucose levels. They also accelerate the breakdown of glucose in skeletal muscles and stored fats in adipose tissue.