biology: endocrine system
TRANSCRIPT
Biology The Endocrine System
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The Endocrine SystemThe 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)
HormonesHormones 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.
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.
Things that cause hormonal changes:
Weight gain Stress
Puberty in Teenage Years 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
AdrenalHypothalamus
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.
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.
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.
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.
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.
Nature vs.
Nurture
back to…
Nature vs. Nurture DebateNature:
!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.
?
Nature vs. Nurture DebateAn 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.”
?
EpigeneticsThis 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.
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.
EpigeneticsQ: 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.
Nature vs. NurtureFor 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?