We talk about our hormones a lot.
Estrogen is the “female” hormone, while testosterone is the “male” hormone.
Hormonal changes affect growth and development , mood, and more.
However, that is only the tip of the iceberg.
Your body produces 50 different hormones that regulate everything in your body.
You name it and there’s probably a hormone or three regulating it: from sleep, hunger
and mood to reproduction and metabolism, hormones work hard to keep the body balanced, aka in
homeostasis.
In this video, we’ll look at some of the body’s key glands and their hormones.
The major endocrine glands in the body are the hypothalamus, pituitary gland, and pineal
gland in the brain, the thyroid and parathyroid glands near the neck, the adrenal glands on
top of the kidneys , the pancreas nestled behind your stomach, and the gonads: testes
in males and ovaries in females.
Let’s begin at the top with the glands in the brain: the hypothalamus, the pituitary
gland, which is connected to the hypothalamus, and the pineal gland.
The pituitary gland is further divided into two lobes: the anterior pituitary and the
posterior pituitary.
First, let’s consider the hormones of the anterior pituitary.
The anterior pituitary gland produces growth hormone (GH), prolactin, thyroid-stimulating
hormone (TSH), the adrenocorticotropic hormone (ACTH), F ollicle Stimulating Hormone (FSH)
and Luteinizing hormone (LH).
Growth hormone (GH), as the name implies, affects the growth of nearly every organ,
but most notably, it impacts the growth of the bones and cartilage that determine your
physical size and shape . Prolactin is primarily responsible for lactation
and the development of breasts in females.
The anterior pituitary also produces hormones that have the sole function of bossing around
other glands to properly produce their hormones.
For example, the thyroid-stimulating hormone (TSH) stimulates the thyroid glands to produce
the thyroid hormone.
The adrenocorticotropic hormone (ACTH) stimulates the adrenal glands to produce some of their
critical hormones.
Follicle Stimulating Hormone (FSH) and Luteinizing H ormone (LH) are involved in the sexual development
and reproduction of both males and females.
FSH and LH stimulate the gonads to secrete sex hormones, such as estrogen, progesterone
and testosterone.
They are responsible for regulating the menstrual cycle in females.
The anterior pituitary takes its commands from the hormones produced by the hypothalamus.
This creates a chain of command, a hierarchy, or an ‘axis’.
The hypothalamus receives signals from the brain and the body, responding to them by
secreting hormones to signal the anterior pituitary.
The anterior pituitary releases its hormone signals to a specific gland to release its
final hormone.
Next, the posterior pituitary secretes two hormones, antidiuretic hormone or vasopressin,
and oxytocin.
Vasopressin helps control blood pressure by balancing the amount of salt and water in
the body.
Oxytocin is involved in childbirth, as it stimulates contractions in the uterus.
It is also called the love hormone, because it is released when you’re sexually aroused
. The posterior pituitary doesn’t make the
hormones.
The hypothalamus produces the hormones and transports them to the posterior pituitary
via neurons.
As you can see, the hypothalamus is the “head” honcho around here, no pun intended, and along
with the anterior pituitary gland, the hypothalamus is often called the master gland.
F inally, the pineal gland receives information about whether it is light or dark outside.
When it’ s dark, it produces the hormone melatonin, which helps you get to sleep .
The next gland is the thyroid gland, the largest true endocrine gland; it is shaped somewhat
like a butterfly, and is located in the neck , below the voice box.
It produces and secretes the thyroid hormone Thyroxine (T4).
This increases overall basal metabolism, making cells work harder.
Thyroxine is converted to triiodothyronine or T3 at the target cell.
T3 is more active than T4.
Iodine is a crucial part of the structure of T4 and T3, but our body can’ t produce
that element . We get iodine mainly from our diet, particularly from the iodized salt you
sprinkle on your food . When there isn’t enough thyroid hormone,
the hypothalamus via the anterior pituitary’s TSH, stimulates the thyroid to produce more
thyroid hormone.
If you want to learn more about the endocrine system’s feedback mechanisms, they are discussed
in detail in another video.
The thyroid gland also produces calcitonin, which regulates calcium levels by decreasing
the calcium levels in the blood.
The next glands are the parathyroid glands, two pairs of tiny pea- sized glands next to
the thyroid gland.
They produce parathyroid hormone, which regulates calcium levels by increasing the calcium levels
in the blood.
Calcium is not only important for bone health, but is also involved in other processes, such
as muscle contraction and blood clotting.
Too much calcium can actually weaken your bones and cause kidney stones!
Next up is the pancreas.
The endocrine function of the pancreas is primarily involved in regulating blood glucose
levels.
The most famous hormone of the pancreas is insulin, which decreases blood glucose levels
by making it possible for cells to take in glucose.
Without insulin, your cells can’ t take in the glucose.
This usually happens in Type-1 diabetes, when the pancreas cannot produce and secrete enough
insulin.
Sometimes, your cells become less sensitive to the hormone, either because of stressors,
too much sugar or cortisol, or some other disease.
This can also prevent your cells from taking in glucose, and is known as Type-2 diabetes.
The pancreas also secretes glucagon, which increases blood glucose levels by promoting
the release of the glucose stored in the liver.
Next up are the adrenal glands, which are divided into two parts: the adrenal medulla
and the adrenal cortex.
The adrenal cortex secretes a class of hormones called glucocorticoids.
However, you probably only know of cortisol, which is one type of glucocorticoid.
Cortisol regulates metabolism, cell division, inflammation and immune function.
The body always produces base levels of cortisol, b ut when we’re faced with stress or danger,
the hypothalamus, via the anterior pituitary gland’s ACTH, signals the adrenals to secrete
more cortisol.
The next class of hormones are mineralocorticoids, such as aldosterone.
This hormone regulates the levels of minerals, such as sodium, potassium and hydrogen ions,
which affect blood pressure and metabolic reactions in the body.
Lastly, the adrenal cortex produces a tiny amount of androgens, or sex hormones, which
work along with the main sex hormones for reproduction.
The a drenal medulla secretes adrenaline/epinephrine and noradrenaline/norepinephrine.
This initiates our fight-or-flight response when something dangerous or stressful happens.
Then there are the gonads.
The gonads, typically testes in males and ovaries in females, also produce hormones,
most notably estrogen, progesterone and testosterone.
The various sex hormones control and regulate different parts of the menstrual cycle in
females, and sperm production in males.
FSH and LH, from the anterior pituitary, regulate the production and secretion of sex hormones
from the ovaries and testes.
During puberty, all these hormones affect the body’s growth and development, in both
males and females.
In females, estrogen causes the bones to stop growing quicker, which is why females stop
getting taller earlier than males.
It is a myth that one or the other hormone from the gonads is a “female” or “male”
hormone . Every human has all three of these hormones.
What differs between the bodies of the average female and male are the levels of these hormones.
Males tend to have more testosterone, while estrogen and progesterone levels tend to be
higher in females.
As you can imagine, hormones frequently step on each other’s toes.
Insulin regulates glucose metabolism, but so does cortisol, the thyroid hormone and
growth hormone.
Estrogen can impact calcium stores in our bones.
The kidneys produce renin, which regulates blood pressure, and interacts with adrenal
hormones.
And all of this is further affected by the nervous system and our environment!
This mind-boggling interconnectedness is what helps your body subtly react to the myriad
cues it gets every day without completely falling apart.
So, in effect, everyone is pretty much “hormonal” all the time, not just when you’re an angsty
teenager!