The Sympatho-Adrenal Medullary (SAM) system, when activated, primarily triggers the release of crucial stress hormones and subsequently stimulates significant physiological changes in the body, preparing it for immediate action.
When the nervous system initiates a response to stress, it rapidly activates the SAM system. This activation culminates in a cascade of effects designed to enhance an individual's capacity to confront or escape perceived threats, a process often referred to as the fight or flight response.
Key Hormones Activated and Released
A primary function of the activated SAM system is the rapid secretion of a group of hormones known as catecholamines. These powerful neurotransmitters and hormones are vital for mediating the body's acute stress response.
- Adrenaline (Epinephrine): Often known as the "fight or flight" hormone, adrenaline is released in large quantities, preparing the body for intense physical exertion.
- Noradrenaline (Norepinephrine): Similar to adrenaline, noradrenaline also plays a critical role in vigilance, arousal, and increasing blood flow to muscles.
These catecholamines are released into the bloodstream, allowing them to exert widespread effects throughout the body.
Physiological Changes Stimulated by SAM Activation
The release of adrenaline and noradrenaline, a direct consequence of SAM system activation, leads to several immediate and notable physiological adjustments:
| Physiological Change | Description | Primary Stimulating Hormone(s) |
|---|---|---|
| Increased Heart Rate | The heart beats faster, pumping more blood per minute. | Adrenaline, Noradrenaline |
| Elevated Blood Pressure | Blood vessels constrict, raising the pressure of blood circulation. | Adrenaline, Noradrenaline |
These changes are fundamental in diverting resources to essential functions needed for survival in a stressful situation. For instance, the increased heart rate and higher blood pressure ensure that more oxygen and nutrients reach critical organs like the brain and muscles, enhancing the body's readiness for physical activity. The overall effect contributes to heightened awareness and reactivity, allowing for quicker decision-making and response in a perceived emergency.
