Chemistry of a first year’s body

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The transition to university from secondary education can be monumental in a young person’s life. Old friendships break down while new ones form; you find new interests and uncover more about yourself than ever before. Many visible changes happen during this time –  but let’s look at what’s going on behind the scenes in a fresher’s body. Let’s get molecular.

It’s your first day of college life. Front Square is packed with society stalls and other new students like you, and the entire situation can become a little daunting. Although it might feel like you’ve eaten half a kilo of butterflies and they are fluttering around your stomach, what’s actually happening is caused by adrenaline. Adrenaline, otherwise known as the ‘fight-or-flight’ hormone, is a catecholamine (a certain class of carbon-based compound) and it is currently restricting the flow of blood to your stomach in response to the several society membership cards being fired at you. Thankfully you find an old school friend and go and grab a big steamy cup of everyone’s favourite crystalline stimulant, caffeine. Caffeine starts to counteract the adenosine receptors in your body, reducing blood flow to your internal organs and fighting of the sleepiness caused by last night’s Netflix binge.

Fast forward to your first night out on the town with your college course, and you have decided to hit the nearest club. As the tunes begin to drop, so do the tequila shots. Alcohol is one of the most commonly ingested substances in Ireland, with your average young adult, aged 18 to 25, consuming the equivalent of 10.73 litres of pure alcohol a year, according to 2013 figures. Your body tackles alcohol by metabolising it into a compound called ethanal, and then changes it again into ethanoic acid – the main constituent in vinegar. This is the reason why we say a bottle of wine has gone ‘bad’ when it tastes like vinegar; the ethanol in the wine has been oxidised to ethanoic acid by the oxygen in the atmosphere.

By the time all of the new songs have been played (and somebody has requested the Macarena), you spot someone you fancy from across the floor. Again the adrenaline starts to pump, but you pluck up the courage to go talk to them.  If you play your cards right, you might end up with a huge influx of the hormone oxytocin in your bloodstream. When a situation becomes a little R rated, this little neurohypophysial (meaning it comes from a specific part in the brain called the posterior pituitary gland) hormone causes pair bonding, sexual arousal and has a key role in orgasm. It is also closely related to the formation of trust between mammals. Studies have shown that when remembering a negative event, humans who received intranasal oxytocin doses shared more emotional details and stories with more emotional significance.

The next morning hits, and so does the hangover. Stumbling from bed, you opt for good old aspirin, a compound originally discovered in willow bark by the father of modern medicine, Hippocrates. This small molecule known chemically as acetylsalicylic acid begins to suppress the production of prostaglandins and thromboxanes, two classes of chemicals which cause fever and pain in animals.  Not satisfied with just aspirin, you use the oldest trick in the book to cure a hangover: the big greasy fry up.

Although some people argue that there’s no cure for a hangover other than lots of water and rest, there is substantial evidence that the full Irish breakfast works wonders. Speaking as head of the International Alcohol Hangover Research Group, Professor Richard Stevens of Keele University, says the carbohydrates in a full Irish will help restore depleted glucose levels and lessen the effects of the hangover. “One of the mechanisms of the hangover is to do with glucose metabolism and not having enough blood sugar. [The full Irish] probably does work because there are lot of carbohydrates in that meal. And that will restore depleted sugar levels.”

For our final snapshot, let’s go forward to the week before your exams.  Including adrenaline and (probably) a tonne of caffeine, your bloodstream is full of cortisol. Cortisol, often sold as hydrocortisone, is a powerful steroid hormone which is released in response to stress. Cortisol actually redistributes energy to the regions of the body which need it most in tight situations, so this little helper is pushing glucose to your brain as you scribble down the last few pages of notes on model organisms and fungal reproduction at three o’clock in the morning. At the same time, another hormone is fighting to drag you to bed. Melatonin (not to be confused with melanin, the primary determinant of skin colour) is a hormone found in plants and animals which helps regulate your circadian rhythm; a sort of “human biological clock” that last roughly 24 hours and tells your brain when to sleep. Caffeine can only suppress adenosine (the ‘drowsiness’ chemical) for so long before you collapse into bed.

Having fought off your body clock for a week or two, the exams are over and you can breathe a sigh of relief.  A hormone called serotonin that regulates both mood and appetite begins to flow through your blood stream and your stress levels finally start to decrease. A new wave of relaxation and repair hormones are released through your system in response to psychological stress. The first year of college may be over, but your body chemistry never stops changing and adapting. All of these changes will repeat themselves in the future, but hopefully with more serotonin and less caffeine next year!

Illustration: Natalie Duda

Dylan Lynch

Dylan is an SF Medicinal Chemist studying at Trinity College Dublin, and is the Science & Technology Editor.