WHAT ARE CATECHOLAMINES?

The  nervous system consists of the central and the peripheral nervous systems. The central nervous system consist of the brain and spinal cord while the peripheral nervous system is made up of the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is responsible for fight-and-flight responses whilst the parasympathetic is responsible for calming you down. 

Within the sympathetic nervous system, there are two neurotransmitters: 

• Noradrenaline (also referred to as norepinephrine)
• adrenaline (also referred to as epinephrine)

These are known as catecholamines. 

• Noradrenaline is the main neurotransmitter of the sympathetic nerves in the cardiovascular system. It plays a major role in tonic and reflexive changes in cardiovascular tone. The sympathetic noradrenergic system is active even when the individual is at rest.
•  Adrenaline is the main hormone secreted by the adrenal medulla. Adrenaline is a major determinant of responses to metabolic challenges to homeostasis.  

What are some of the fight-and-flight responses?

• Increased alertness
• Pupil dilatation
• Increased heart rate
• Increased respiratory rate
• Decrease intestinal motility
• Decreased bladder contraction
• Vasoconstriction (constriction of blood vessels)
• Increased blood pressure