Epinephrine

Definition

Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced by the adrenal glands that plays a critical role in the body's response to stress and injury. It prepares the body for 'fight or flight' by increasing heart rate, blood flow to muscles, and energy availability, making it essential in the metabolic response during stressful situations.

5 Must Know Facts For Your Next Test

1. Epinephrine is rapidly released into the bloodstream in response to stressors such as injury, danger, or anxiety.
2. It enhances glycogenolysis and gluconeogenesis in the liver, increasing glucose availability for energy production.
3. Epinephrine increases heart rate and cardiac output, ensuring vital organs receive adequate blood supply during stress.
4. It causes bronchodilation, which improves airflow in the lungs, allowing for better oxygen uptake during physical exertion.
5. The effects of epinephrine are typically short-lived due to its quick breakdown by enzymes in the body, but its impact is critical for immediate survival.

Review Questions

• How does epinephrine influence metabolic processes during stress?
  • Epinephrine significantly influences metabolic processes during stress by promoting the breakdown of glycogen into glucose in the liver through glycogenolysis. It also stimulates gluconeogenesis, which helps create new glucose from non-carbohydrate sources. This increase in glucose availability provides a rapid energy source for muscle cells and vital organs, enabling an effective response to stressful situations.
• Evaluate the role of epinephrine within the sympathetic nervous system during an emergency situation.
  • Epinephrine acts as a key player within the sympathetic nervous system during emergencies by initiating the 'fight or flight' response. When faced with danger, epinephrine is released into the bloodstream, leading to increased heart rate, heightened blood pressure, and enhanced blood flow to muscles. This hormonal surge prepares the body for quick physical action and ensures that it can respond effectively to life-threatening situations.
• Assess how the interplay between epinephrine and glucagon affects energy metabolism under stress conditions.
  • Under stress conditions, both epinephrine and glucagon work synergistically to enhance energy metabolism. While epinephrine increases glucose availability through glycogenolysis and stimulates lipolysis for fat utilization, glucagon complements these actions by promoting additional glucose release from liver stores. This interplay ensures a sufficient supply of energy substrates needed for immediate physical activity and survival during acute stress or injury.

Related terms

Catecholamines: A group of hormones that includes epinephrine and norepinephrine, released during stress that affect the cardiovascular system and metabolism.

Sympathetic Nervous System: The part of the autonomic nervous system that prepares the body for stressful or emergency situations, activating the 'fight or flight' response.

Glucagon: A hormone produced by the pancreas that raises blood glucose levels, complementing the actions of epinephrine during stress by mobilizing energy stores.