Fight or Flight Response Flashcards
What is the fight or flight response?
An adaptation that helps us to survive when we face a threat. The response is mainly due to the sympathetic nervous system and the hormone adrenaline.
When is the sympathetic nervous system activated?
When we are faced with stressful or high-arousal situations. The activity of this system was adaptive for our ancestors and increased their chances of survival.
What happens to the body when the fight or flight response is activated?
Pupils dilate, heart rate and blood pressure increase, the bladder relaxes, the liver releases glucose, and adrenaline surges into the bloodstream.
This series of physiological changes allows the body to access energy reserves and heightened sensory capacity so that it might fight off a threat or run away to safety.
What happens after the threat has been resolved?
The parasympathetic nervous system takes over and returns bodily functions to a relaxed state. Heart rate and blood pressure return to normal, pupils constrict, control of the bladder is regained, and the liver begins to store glucose in the form of glycogen for future use.
These processes happen when the parasympathetic nervous system is activated.
What are the two systems generally involved in the physiological mechanisms of stress?
The sympathetic nervous system and the hypothalamic-pituitary-adrenal (HPA) axis.
What does the sympathetic nervous system trigger when a person perceives something as something stressful?
The sympathetic nervous system triggers arousal via the release of adrenaline from the adrenal glands. Releasing these hormones activates the fight-or-flight responses to stress, such as accelerated heart rate and respiration.
What does the adrenocorticotropic hormone activate?
ACTH activates the adrenal glands to secrete a number of hormones into the bloodstream. An important hormone is cortisol, which can affect almost every organ within the body.
What does cortisol provide?
Cortisol is commonly known as a stress hormone. It helps provide that boost of energy when we first encounter a stressor, preparing us to run away or fight. But sustained elevated levels of cortisol weaken the immune system.
