Download endocrine system

Functions of hormones
in human behaviour
The IB Syllabus Says….
• Using one or more examples,
explain the functions of two
hormones in human behavior
What are hormones?
• Hormones are chemicals that
affect behavior.
• They are produced by the glands
that make up the endocrine
system
The Endocrine System &
Hormones
• Endocrine glands secrete chemicals called hormones directly into
the bloodstream where they are carried to all parts of the body
• Like neurotransmitters, hormones have receptor cites – so some
hormones only effect certain parts of the body
• The effects of hormones is slower than neural transmission – it
may be minutes or hours before the response occurs and the
effects are longer lasting
• Hormones enter directly into the bloodstream, so they take longer
to produce changes in behaviour than neurotransmitters. Some
chemicals serve as both hormones and neurotransmitters.
• Note: Neural and hormonal processes are complementary
Hormones and their functions….
Some important glands….
• Hypothalamus – secretes hormones which then influence the pituitary
gland to secrete corresponding hormones (see stress response)
• The pituitary gland ‘ the pea sized governor’ or ‘master gland’ secretes
hormones into the body maintaining homeostasis – this steady state relies
on a feedback loop – when enough of a hormone has been secreted – the
gland then stops producing that hormone
• The adrenal glands are located above the kidneys is play an important role
in the stress response, it regulated by ACTH from the pituitary gland. The
adrenal glands secrete corticosteroids – which increase resistance to stress
promote muscle development and cause the liver to release stored sugar –
making energy available in emergencies
• Adrenal medulla – produces epinephine (adrenaline) and norepineprine
(nor-adrenaline) – which heightens emotional responsiveness – but the
specific emotion may depend on the persons situation. The sympathetic
branch of the nervous system causes the adrenal medulla to release a
mixture of adrenaline and noradrenaline in times of stress
The effect of the hormone Oxytocin
on behavior….
• Oxytocin is a hormone that is produced by the hypothalamus
after being stimulated by the pituitary gland.
• As a hormone, it plays a role in inducing labour contractions
and lactation.
• Oxytocin is released with touches and hugs. It is associated
with bonding between a mother and her child as well as
between lovers.
• Oxytocin appears to change the brain signals related to social
recognition via facial expression, perhaps by changing the firing
of the neurons of the amygdala.
The effect of the hormone Oxytocin
on behavior….
• The amygdala plays an important role in processing emotional
stimuli. Oxytocin has been called “the love hormone” because it
seems to be such an effective mediator of human social
behaviour.
• If oxytocin is given to healthy individuals it seems that brain
circuits involved in fear regulation are affected, and there is an
increase in trust and generosity.
• Kosfiled et al (2005) carried out a clinical trial with 194 male
participants and found that those who received a intranasal
dose of Oxytocin were more likely to be more trusting in a role
play situation, than participants who received a placebo.
• Research is being carried out to see whether people suffering
from social anxiety may benefit from doses of oxytocin.
The effect of the hormone Melatonin on
behavior….
• Through the study of the hormone melatonin, researchers hope to find a
solution for those who suffer from insomnia (the inability to fall asleep) and
jet lag.
• The production of melatonin by the pineal gland is stimulated by darkness
and inhibited by light.
• Melatonin levels in the bloodstream peak in the middle of the night, and
gradually decrease towards morning. As the days get shorter and winter
approaches, the earlier onset of darkness means that we can become tired
earlier.
• Until recent history, humans in temperate climates had up to 18 hours of
darkness in the winter months. The use of artificial lighting has increased the
“awake time” dramatically.
• Melatonin release correlates with the circadian rhythm—the biological clock
that is based on a 24-hour day/night cycle. It is suggested that taking
melatonin in the early evening may improve one’s ability to fall asleep.
The effect of the hormone Melatonin on
behavior….
• However, there is some evidence (Rosenthal 1987) that higher levels
of melatonin contribute to seasonal affective disorder (SAD)—a
subcategory of depression that is characterized by sleepiness and
lethargy—as well as cravings for carbohydrates.
• Reduced levels of sunlight in autumn and winter are believed to
disrupt the circadian rhythm in certain people, leading to this form of
depression.
• This is perhaps why we see higher levels of SAD in Scandinavia. As
increased sunlight improves the symptoms, phototherapy is often the
main treatment for people with SAD. In phototherapy, people are
exposed to bright light for several hours each day.
• Despite claims of some success with this treatment, there is a lack of
definitive evidence of its effectiveness. Whether it is light therapy to
combat depression or melatonin pills to aid sleep, one has to be
careful about seeking quick solutions to complex questions.
Mini presentations….
Prepare to give a mini presentation, also prepare 5
questions to ask the audience
• Group 1: What hormones are/ what the endocrine
system is/ Some hormones and their functions
• Group 2: The effect of the hormone Oxytocin on
behavior
• Group 3: The effect of the hormone Melatonin on
behavior.
1.
2.
3.
4.
Quick quiz on hormones & behavior
What are hormones?
What is the name of the bodies hormonal system?
Do hormones travel faster or slower than neurotransmission?
What are the names of three glands and three hormones associated with these
glands?
5. What is another name for the pituitary gland?
6. What hormones do the adrenal glands release?
7. What behaviors is Oxytocin associated with in pregnant women?
8. What can trigger the release of Oxytocin?
9. What has Oxytocin been called?
10. What are the aims, procedures, findings and conclusions of Kosfield et al. (1995)
study? (include the IV & DV)
11. What mental disorder might Oxytocin help treat?
12. For what reasons have people studied the effects of the hormone Melatonin?
13. What glands are associated with the production of Melatonin?
14. When are levels of Melatonin at their peak in the endocrine system?
15. What medications contain Melatonin?
16. What mental disorder did Rosenthal et al. (1987) connect high levels of melatonin to?
17. What are the symptoms of the above mental disorder?
18. Why does the said mental disorder occur? And in what countries is it a major
problem?
19. What treatment is recommended for this mental disorder?
20. If we give simple biological explanations for complex behaviors, this can be called
…………………….
1.
2.
3.
4.
Quick quiz on hormones & behavior
What are hormones?
What is the name of the bodies hormonal system?
Do hormones travel faster or slower than neurotransmission?
What are the names of three glands and three hormones associated with these
glands?
5. What is another name for the pituitary gland?
6. What hormones do the adrenal glands release?
7. What behaviors is Oxytocin associated with in pregnant women?
8. What can trigger the release of Oxytocin?
9. What has Oxytocin been called?
10. What are the aims, procedures, findings and conclusions of Kosfield et al. (1995)
study? (include the IV & DV)
11. What mental disorder might Oxytocin help treat?
12. For what reasons have people studied the effects of the hormone Melatonin?
13. What glands are associated with the production of Melatonin?
14. When are levels of Melatonin at their peak in the endocrine system?
15. What medications contain Melatonin?
16. What mental disorder did Rosenthal et al. (1987) connect high levels of melatonin to?
17. What are the symptoms of the above mental disorder?
18. Why does the said mental disorder occur? And in what countries is it a major
problem?
19. What treatment is recommended for this mental disorder?
20. If we give simple biological explanations for complex behaviors, this can be called
…………………….
SAQ…
• Using one or more examples,
explain the functions of two
hormones in human behavior
SAQ writing workshop
• 1st paragraph: Outline how you will answer the question,
identifying the two hormones you will write about, and briefly
mention the endocrine system
• 2nd paragraph: Explain the effect of Oxytocin on behavior, be
sure to integrate Kosfield et al (1995), and at the end of the
paragraph clearly connect back to the which is asking about
its effect on behavior
• 3rd paragraph:
• Explain the effect of Melatonin on behavior, be sure to
integrate Rosenthal et al. (1987), and SAD and at the end of
the paragraph clearly connect back to the which is asking
about its effect on behavior
• 4th paragraph: Conclusion – although hormones are
influential, other factors also play an important role in
behavior – its important not to be reductionist.
HW
• Complete SAQ on the effects of hormones
on behavior and submit by email to
[email protected] before Mondays
lesson.