endocrine system

• endocrine system is the main chemical messenger system of the body, where hormones are secreted into the bloodstream from glands, and then are transported towards target cells in the blood, with complementary receptors.
• The pituitary gland is considered to be the ‘master’ gland because it controls the release of hormones from all other glands in the body. For example, the thyroid releases the hormone thyroxine, which increases heart rate and therefore increases the rate of growth.
• The adrenal gland releases adrenaline which creates the physiological arousal preceding the fight or flight response, through increasing the activity within the sympathetic branch of the nervous system. The fight or flight response .
• The body senses and becomes aware of a stressor in the environment e.g. the sound of a speeding car.
• Through sensory receptors and sensory neurones in the PNS, this information is sent to the hypothalamus in the brain which coordinates a response and triggers increased levels of activity in the sympathetic branch of the ANS.
• 3.Adrenaline is released from the adrenal medulla in the adrenal glands, and is transported to target effectors, via the blood and through the action of the endocrine system
• 4. This results in the rectum contracting, saliva production being inhibited and a greater breathing rate. This creates the physiological response needed to sustain the fight or flight response, whose adaptive purpose is to enable us to escape the stressor and so increase the likelihood of our survival.
• Once the stressor is no longer a threat, as part of an antagonistic pairing, the hypothalamus triggers less activity in the sympathetic branch and more activity in the parasympathetic branch of the ANS. This is also referred to as the rest and digest response, due to the parasympathetic branch decreasing the activity which was originally increased through the action of the sympathetic branch.
• The fight or flight response is typically a male response to danger and more recent research suggests that females adopt a ‘tend and befriend’ response in stressful/dangerous situations. According to Taylor et al. (2000), women are more likely to protect their offspring (tend) and form alliances with other women (befriend), rather than fight an adversary or flee. Furthermore, the fight or flight response such as running (flight) might be seen as a sign of weakness and put their offspring at risk of danger.
• Early research into the fight or flight response was typically conducted on males (androcentrism) and consequently, researchers assumed that the findings could be generalised to females. This highlights a beta bias within this area of psychology as psychologists assumed that females responded in the same way as males, until Taylor provided evidence of a tend and befriend response.
• the fight or flight response is a useful survival mechanism for our ancestors, who faced genuinely life-threatening situations. modern day life rarely requires such an intense biological response. Stressors of modern day life can repeatedly activate the fight or flight response, which can have a negative consequence on our health.
• humans who face a lot of stress and continually activate the sympathetic nervous system, continually increase their blood pressure which can cause damage to their blood vessels and heart disease. This suggests that the fight or flight response is a maladaptive response in modern-day life.