Endocrine system + the fight or flight response

Question 1

Endocrine system

Answer 1

-The endocrine system is a network of glands that secrete hormones
-Hormones are chemical messengers that travel in the bloodstream towards target organs
-It regulates physiological processes such as metabolism, growth, and mood
-The endocrine system works closely with the nervous system, but acts more slowly and has longer-lasting effects

Question 2

Hormones

Answer 2

-Hormones are chemical messengers secreted by glands
-Hormones travel in the blood towards target organs
-Hormones only affect target cells that have a specific receptor for the hormone

Question 3

Pituitary gland

Answer 3

-The pituitary gland controls the secretion of hormones from other glands; regulates reproduction and growth
-Can be divided into two parts:
-Anterior pituitary: releases ACTH which stimulates the adrenal cortex
-Posterior pituitary gland: secretes hormones like oxytocin
-Pituitary gland is regulated by the hypothalamus
-Located at the base of the brain, below the hypothalamus

Question 4

Hypothalamus

Answer 4

-Links the nervous system to the endocrine system
-Regulates the pituitary gland
-Releases the hormone CRH which is detected by the pituitary gland during the fight or flight response
-Located in the brain, above the pituitary gland

Question 5

Adrenal gland

Answer 5

-Secretes adrenaline and cortisol
-Involved in the stress response (fight or flight)
-Located at the top of each kidney

Question 6

Thyroid gland

Answer 6

-Thyroid gland regulates metabolism and heart rate by releasing thyroxine
-Located in the neck (front)

Question 7

Pineal gland

Answer 7

-Pineal gland regulates sleep patterns by keeping the body to a day/night circadian rhythm

Question 8

Pancreas

Answer 8

The pancreas regulates blood sugar levels by secreting insulin and glucagon
-Problems with this system can cause diabetes

Question 9

Ovaries/testes

Answer 9

-Ovaries: Ovaries regulate the menstrual cycle and reproduction by releasing oestrogen and progesterone and affects development of female characteristics
-Testes: regulate sperm production in males and affects development of male characteristics
-Both are located in the lower abdomen/pelvic region

Question 10

Differences between the endocrine system and the nervous system

Answer 10

-The endocrine system acts much slower than the nervous system but has longer-lasting effects
-The endocrine system uses hormones via the bloodstream whereas the nervous system uses electrical impulses via neurones

Question 11

What is the fight or flight response

Answer 11

-The fight or flight response is a biological response to stress or threats
-This causes a physiological response that prepares the body to either fight (confront the threat) or flight (run from the threat)
-This involves the endocrine system and the autonomic nervous system; particularly the sympathetic branch of the ANS

Question 12

Acute stress response (fight or flight) (immediate)

Answer 12

-Perceived threat (stressor) is detected by the hypothalamus
-The hypothalamus activates the sympathetic branch of the autonomic nervous system
-The adrenal medulla is stimulated, causing it to release adrenaline and noradrenaline
-These hormones cause several physiological changes to prepare the body for action

Question 13

Physiological effects of adrenaline (effect and purpose)

Answer 13

-Increased heart rate: to pump more oxygenated blood to muscles
-Increased breathing rate: increased oxygen intake
-Pupil dilation: improved vision
-Inhibited digestion: to conserve energy
-Redirected blood flow: to direct blood toward muscles and away from non-essential systems

Question 14

Parasympathetic nervous system-after the threat has passed

Answer 14

-After the threat has passed, the parasympathetic branch of the autonomic system is activated, triggering the rest and digest response
-This involves restoring the body to a calm, resting state
-Involving reducing heart rate/breathing rate, constriction of pupils, and stimulation of digestion/salivation

Question 15

HPA axis - chronic stress response

Answer 15

-If the stress is ongoing then the HPA axis is activated;
-the hypothalamus releases CRH
-CRH is detected by the pituitary gland
-Pituitary gland releases ACTH
-ACTH stimulates adrenal cortex which produces cortisol
-Cortisol helps to maintain energy levels by releasing glucose
-However cortisol can suppress the immune system if there is too much for too long

Question 16

Fight or flight evaluation (Gray 1998) “freeze” response and (Taylor 2002) gender differences

Answer 16

-Research suggests that the fight or flight response does not fully explain all human responses to stress
-For example (Gray 1998) argued that humans display a “freeze” response before the fight or flight response occurs- when individuals pause to asses a threat before reacting
-Additionally, Taylor (2002) found that women often engage in “tend and befriend” behaviours; where they protect their offspring and seek social support- this is because of evolutionary pressures associated with caregiving
-This suggests that the “fight or flight” theory is biologically reductionist and gender biased, as it mostly focuses on male responses and does not take into account alternate strategies

Question 17

Fight or flight evaluation (strong evolutionary support)

Answer 17

-The fight or flight theory has a strong evolutionary support, as it explains how organisms survive immediate threats
-In early humans, quickly preparing the body to either fight a threat or flee it, increased survival chances in hostile environments

Question 18

Fight of flight evaluation (face validity)

Answer 18

-The fight or flight theory has face validity, as it explains physiological changes such as increased heart rate an pupil dilation, which can be observed and measure in real life acute stress situations