Hormones

Hormones - special chemical messengers in the body that are created in the endocrine glands. These messengers control most major bodily functions, from simple basic needs like hunger to complex systems like reproduction, and even the emotions and mood.

• Estrogen - the main sex hormone. It causes puberty, prepares the body and uterus for pregnancy, and regulates the menstrual cycle. During menopause, estrogen level changes cause many of the uncomfortable symptoms women experience.

• Progesterone - similar to estrogen but not considered the main sex hormone. Like estrogen, it assists with the menstrual cycle and plays a role in pregnancy.

• Cortisol - has been called the ‘stress hormone’ because of the way it assists the body in responding to stress. It does not cause stress, it releases it as a consequence of stress.

• Melatonin - levels changes cause throughout the day, increasing after dark to trigger the responses that cause sleep.

• Testosterone - the main sex hormone in men. It causes puberty, increases bone density, triggers facial hair growth, and causes muscle mass growth and strength.

Testosterone

• Testes inside testicles

• Released in higher quantities during puberty. Main sex hormone.

• Higher rates of testosterone have been linked to aggressive behaviour.

• The effect of testosterone is aggression.

Cortisol

• Adrenal gland

• Stress hormone

• Released to support the body during high levels of stress to aid the functioning of immune system- reducing inflammation in the body.

• A balance is key.

• Too much can weaken the immune system causing inflammation. This destroys the number of white blood cells in the immune system and vulnerable to illness. Reduce function of memory.

• High cortisol = high in glucocorticoid = destroys neurons in hippocampus = decrease in memory.

• The effect of too much cortisol is poor health/death.

Berthold (1849)

The 3 Rs do not exist yet (not until 1980s)

DO NOT USE IN 9 MARKER

ANIMAL STUDY

• Aim: Testosterone and its role in Aggression in Castrated Roosters

  • Role of testosterone on Male Behaviour

• IV: Testosterone Production

• DV: Impact on Aggressive Behaviour

• Research Method: Observation, Field

Ethics

• ✓ Reduction - Couldn't use smaller number or it could affect validity

Method

• 6 Healthy Roosters were Castrated

• Split into 3 groups

  • Group 1 (Control) - Stayed Castrated

  • Group 2 - Translated Testicles of another rooster

  • Group 3 (Control) - Reimplanted with own testicles
    
    

Results

• Castrated Roosters - ↓ Aggressive, ↓ Masculine, Lost Interest to hens

  • ↓ Crow, Fight, Mate
    
    

• Group 2 and 3 - Behaved normally

• Autopsies of Group 2 and 3

  • Reimplanted Testicles had continuous blood-flow

  • Didn't establish nerve connections

Brady (1958)

The 3 Rs do not exist yet (not until 1980s)

DO NOT USE IN 9 MARKER

ANIMAL STUDY

• Aim: Investigate whether stress of receiving shocks could cause stress-related illness - and whether this changes with the degree of control over the shock

  • Ulcers - Stress Related Disease
    
    

• IV: Choice of Avoidance / Ability to make a choice

• DV: Gastric Ulcers / Health

• Research Method: Lab, Observation

Ethics

• X Reduction - Could've used 4

• ✓ Reduction 

  • They have emotions and personalities like humans - Need more of them to apply it outward to humans

• X Refinement

  • They're killed - Could've just stopped once you can see signs of gastric Ulceration

• ✓ Replacement - Can't Replace with Humans

Method

• 8 Monkeys (4 Groups of 2)

• Pairs of Monkey

  • Executive Animal - Can pull a lever to stop the shock

    • Has the ability to make a choice to stop the shock

  • Yoked Animal - Can do nothing to stop the shock
    
    

• Monkeys received electric foot shocks

  • Shocked from Feet - Electricity travels upwards from the bottom - Loses current as it goes up - Less Impactful on Internal Organs - Want to make sure it's the stress, not the shock, that causes Ulcer

• Signalled by preceding tone - Gives executive animal chance to avoid

Results

• After 23 days 

  • Executive Monkey - Died of Gastric Ulceration (Stomach Ulcer)

  • Yoked Monkey - Remained Healthy

Conclusion

• The shocks themselves were not severely stressful

• Avoiding the shock was more stressful

  • Avoid the Shock -> Causes Stress -> ↑ Cortisol -> Negative Impact on Health

Bremner (2003)

• Aim: Investigate role of PTSD on Hippocampus Volume and Matter

• IV - PTSD

• DV - Hippocampus Volume

• Research Method - Quasi

Method

• 33 Women Participants

• 3 Groups

  • 10 women - early childhood sexual abuse + PTSD

  • 12 women - early childhood sexual abuse, No PTSD (Control Group)

  • 11 women - no abuse, no PTSD (Control Group)
    
    

• MRI to measure Volume of hippocampus

• PET to measure activity of hippocampus during verbal declarative memory test

Results

• Group 1 (SA + PTSD)

  • 16% ↓ volume than Group 2 (SA + NO PTSD)

  • 19% ↓ volume than Group 3 (NO SA + NO PTSD)

• Group 1 - Lack of activity in hippocampus - smaller volume = less activity
  
  

• PTSD impacts size of hippocampus -> Smaller hippocampus causes them to perform worse

Why It Shrinked

• PTSD -> Ongoing Stress -> Body releases cortisol to counter it

• Stress is ongoing -> Cortisol keeps being released -> Large Chemical Imbalance

• Glucocorticoid released to counter imbalance -> More Cortisol = More steroid released -> Neural Death

• Neural Death -> Hippocampus shrinks