Nestled in the tissues of your neck is a small unassuming organ that wields enormous power over your body.
It's called the thyroid.
Like the operations manager in a company, its role is to make sure that the cells in your body are working properly.
It does that by using hormones to deliver messages to every single one of them.
This high-ranking organ is made up of lobules that each contains smaller cells called follicles, which store the hormones the thyroid sends out into your blood.
Two of the most important hormones it produces are thyroxine and triiodothyronine, or T3 and T4.
As messengers, the hormone's job is to instruct every cell in the body when to consume oxygen and nutrients.
That maintains the body's metabolism, the series of reactions our cells perform to provide us with energy.
This hormonal notification from the thyroid gets the heart pumping more efficiently, and makes our cells break down nutrients faster.
When you need more energy, the thyroid helps by sending out hormones to increase metabolism.
Ultimately, the thyroid allows our cells to use energy, grow and reproduce.
The thyroid is controlled by the pituitary gland, a hormonal gland deep in the brain that oversees the thyroid's tasks, making sure it knows when to send out its messengers.
The pituitary's role is to sense if hormone levels in the blood are too low or too high, in which case it sends out instructions in the form of the thyroid- stimulating hormone.
Even in this tightly controlled system, however, management sometimes slips up.
Certain diseases, growths in the thryoid or chemical imbalances in the body can confuse the organ and make it deaf to the pituitary's guiding commands.
The first problem this causes is hyperthyroidism, which happens when the organ sends out too many hormones.
That means the cells are overloaded with instructions to consume nutrients and oxygen.
They become overactive as a result, meaning a person with hyperthyroidism experiences a higher metabolism signaled by a faster heartbeat, constant hunger, and rapid weight loss.
They also feel hot, sweaty, anxious, and find it difficult to sleep.
The opposite problem is hypothyroidism, which happens when the thyroid sends out too few hormones, meaning the body's cells don't have as many messengers to guide them.
In response, cells grow listless and metabolism slows.
People with hypothyroidism see symptoms in weight gain, sluggishness, sensitivity to cold, swollen joints and feeling low.
Luckily, there are medical treatments that can help trigger the thyroid's activities again, and bring the body back to a steady metabolic rate.
For such a little organ, the thyroid wields an awful lot of power.
But a healthy thyroid manages our cells so effectively that it can keep us running smoothly without us even noticing it's there.
My name is Joseph, a Member of Parliament in Kenya.
Picture a Maasai village, and one evening, government soldiers come, surround the village and ask each elder to bring one boy to school.
That's how I went to school -- pretty much a government guy pointing a gun and told my father, "You have to make a choice."
I walked very comfortably to this missionary school, that was run by an American missionary.
The first thing the American missionary gave me was a candy.
I had never in my life ever tasted candy.
So I said to myself, with all these hundred other boys, this is where I belong.
(Laughter) I stayed.
When everybody else was dropping out.
My family moved; we're nomads.
It was a boarding school, I was seven -- Every time it closed you had to travel to find them.
40-50 miles, it doesn't matter.
You slept in the bush, but you kept going.
And I stayed.
I don't know why, but I did.
All of a sudden I passed the national examination, found myself in a very beautiful high school in Kenya.
And I finished high school.
And just walking, I found a man who gave me a full scholarship to the United States.
My mother still lived in a cow-dung hut, none of my brothers were going to school, and this man told me, "Here, go."
I got a scholarship to St. Lawrence University, Upstate New York; finished that.
And after that I went to Harvard Graduate School; finished that.
Then I worked in DC a little bit: I wrote a book for National Geographic and taught U.S. history.
And every time, I kept going back home, listening to their problems -- sick people, people with no water, all this stuff -- every time I go back to America, I kept thinking about them.
Then one day, an elder gave me a story that went like this: long time ago, there was a big war between tribes.
This specific tribe was really afraid of this other Luhya tribe.
Every time, they sent scouts to make sure no one attacked them.
So one day, the scouts came running and told the villagers, "The enemies are coming.
Only half an hour away, they'll be here."
So people scrambled, took their things and ready to go, move out.
But there were two men: one man was blind, one man had no legs -- he was born like that.
The leader of the chiefs said, "No, sorry.
We can't take you.
You'll slow us down.
We have to flee our women and children, we have to run."
And they were left behind, waiting to die.
But these two people worked something out.
The blind man said, "Look, I'm a very strong man but I can't see."
The man with no legs says, "I can see as far as the end of the world, but I can't save myself from a cat, or whatever animals."
The blind man went down on his knees like this, and told the man with no legs to go over his back, and stood up.
The man on top can see, the blind man can walk.
These guys took off, followed the footsteps of the villagers until they found and passed them.
So, this was told to me in a setup of elders.
And it's a really poor area.
I represent Northern Kenya: the most nomadic, remote areas you can even find.
And that man told me, "So, here you are.
You've got a good education from America, you have a good life in America; what are you going to do for us?
We want you to be our eyes, we'll give you the legs.
We'll walk you, you lead us."
The opportunity came.
I was always thinking about that: "What can I do to help my people?
Every time you go to an area where for 43 years of independence, we still don't have basic health facilities.
A man has to be transported in a wheelbarrow 30 km for a hospital.
No clean drinking water.
So I said, "I'm going to dedicate myself.
I'm leaving America.
I'm going to run for office."
Last June, I moved from America, ran in July election and won.
And I came for them, and that's my goal.
Right now I have in place, for the last nine months, a plan that in five years, every nomad will have clean drinking water.
We're building dispensaries across that constituency.
I'm asking my friends from America to help with bringing nurses or doctors to help us out.
I'm trying to improve infrastructure.
I'm using the knowledge I received from the United States and from my community to move them forward.
I'm trying to develop homegrown solutions to our issues because people from outside can come and help us, but if we don't help ourselves, there's nothing to do.
My plan right now as I continue with introducing students to different fields -- some become doctors, some lawyers -- we want to produce a comprehensive group of people, students who can come back and help us see a community grow that is in the middle of a huge economic recession.
As I continue to be a Member of Parliament and as I continue listening to all of you talking about botany, health, democracy, new inventions, I'm hoping that one day in my own little community -- which is 26,000 square km, maybe five times Rhode Island -- with no roads, we'll be able to become a model to help others develop.
Thank you very much.
(Applause)