The endocrine system is made up of glands that produce hormones which regulate various bodily functions like metabolism, growth, mood, and reproduction. The main glands are the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries, and testicles. Hormones are chemicals that control tissues and organs and are involved in processes like reproduction, growth, and immune function. They work slowly compared to the nervous system. Hormonal changes can impact mood, weight, and other factors. The document then discusses various hormones like cortisol, oxytocin, thyroid hormones, estrogen, and testosterone in more detail. It also covers the nature vs nurture debate about how much our

1. Biology
The Endocrine System
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2. The Endocrine System
The endocrine system is a collection of glands in your body
that produce hormones.The hormones regulate metabolism,
growth and development, tissue function, sexual function,
reproduction, sleep, and mood, among other things.
Main Glands:!
pituitary gland
thyroid gland
parathyroid glands
adrenal glands
pancreas
ovaries (in females)
testicles (in males)

3. Hormones
Hormones are powerful chemicals that
help keep our bodies working normally.
They stimulate, regulate, and control the
function of various tissues and organs.
Made by specialized groups of cells within
structures called glands, hormones are
involved in almost every biological process
including sexual reproduction, growth,
metabolism, and immune function.
Unlike the fast-acting chemicals of your nervous system
(neurotransmitters), the hormones of your endocrine
system work slowly in your body.

4. How much of our behavior is hormonal?
Take for example PMS (premenstrual syndrome): emotional and
physical symptoms that women experience sometime during the
10 days before their menstrual cycle (period) begins.Women
might experience mood swings, depression, crying spells, anger,
irritability, anxiety, social withdrawal, or lack of concentration.
…And this is due to chemical
changes within the body!
!
PMS can also cause a lack of
serotonin in the brain,
triggering depression.

5. Things that cause hormonal changes:
Weight gain
Stress
Puberty in TeenageYears
Aging
Menstrual Cycle (women)
Certain diseases
Things that result from hormonal changes:
Changes in mood
Tiredness/fatigue
Unexplained weight loss or gain
Anxiety, irritability, depression
Acne
Thyroid
Pituitary
Ovaries
Testes
Adrenal
Hypothalamus

6. Hormone: Cortisol
It’s released by your hypothalamus gland in high stress situations.The
cortisol in your body causes you to get a quick boost of energy!
(This is good in danger situations) but if you’re stressed all the time,
your body will eventually run out of cortisol.This leaves you feeling
exhausted and apathetic.

7. Hormone: Oxytocin
This hormone is nicknamed “the love hormone” because
whenever you touch someone (even when you hug a friend!),
it is released into your body generating feelings of pleasure.
High levels can increase sex drive, increase trust between
people, and lower stress.
Not having enough oxytocin
released as a child leads to
lower social skills in the future.
Oxytocin level is closely linked
to social functioning, and some
people inherit a gene that
makes their oxytocin levels
naturally higher.

8. Hormones of the Thyroid
The are called Thyroxine (T4) and triiodothyronine (T3). They regulate
your metabolism, which is how fast you grow and burn energy. (Those with
a “high metabolism” are usually skinnier because their bodies burn fat
faster). If your thyroid hormone levels are too high (hyperthyroidism), you
burn energy too fast - leaving you feeling tired and sluggish. If your thyroid
levels are too low (hypothyroidism), you burn energy slowly and will gain
weight. Factors such as chronic stress, nutritional deficiencies, and
inflammation can cause imbalances in these hormones.

9. Hormone: Estrogen
Women have more estrogen then men do, because the ovaries
produce it in great quantities.The amount of estrogen in a woman’s
body changes throughout the month, or throughout the different
phases of her menstrual cycle. At times, it causes irritability,
migraines, depression, and PMS.
As teenagers, men have
low levels of estrogen
and high levels of
testosterone. As they
age, the level of estrogen
increases, which can
cause changes in mood
and personality.

10. Hormone: Testosterone
Men have more testosterone then women do, because the
testicles produce it in great quantities. Men produce about 20
times more testosterone each day than women. In both, it increases
sexual desire, muscle strength, bone density, and metabolism. If
you don’t have enough in your body, it can leave you sluggish,
depressed, unfocused, and disinterested.

11. Nature
vs.
Nurture
back to…

12. Nature vs. Nurture Debate
Nature:
!
Because we inherit
genes from our
parents, we are born
with a certain set of
characteristics.
We clearly inherit
physical traits, but we
also inherit
personality traits and
preferences.
Nurture:
!
The environment
around us impacts the
way our personalities
and preferences
develop.“Nurture” and
“environment” refer to
the home and city we
live in, and how we are
raised by our parents,
teachers, and friends.
?

13. Nature vs. Nurture Debate
An argument for
Nature:
!
“Studies show that
we inherit some
genes that are related
to certain personality
traits.”
An argument for
Nurture:
!
“Often Identical twins
grow up to have
very different
personalities and
preferences.”
?

14. Epigenetics
This is a new branch of genetics that is shedding light
on the “nature vs. nurture” debate.
“Epi” means “around” or “on top of” so epigenetics refers to
modifications that occur on top of your genes. Environmental
factors actually cause your cells and genetic code to change
over your lifetime. Your genetic code itself is always the same,
but genes can be “turned on” or “turned off.”
For example, your diet can cause
“epigenetic changes” to your DNA. It
is possible to pass these changes on
to your offspring’s DNA.

15. Epigenetics
The DNA of twins begins the same, but over the course of
their lives, different health choices and environmental stimuli
cause the DNA code to change.

16. Epigenetics
Q: What does this mean for the nature vs. nurture debate?
!
A: That we are not defined by our genes. Our lifestyle choices can
actually impact our genetic codes, causing certain genetic traits to
express themselves more or less strongly.
But, this does not mean that our genes don’t impact who we are.
The nature vs. nurture debate rages on as psychologists try to
understand which plays a larger part in our development. They also
try to discover which plays a larger part in specific behaviors - like
gender expression.

17. Nature vs. Nurture
For example, is there a biological reason why girls like dolls and
the color pink? Is there a biological reason why boys like toy cars
and the color blue? Or is this something that children are
nurtured to like by their parents and other societal factors?