36 SCIENCE & ENGINEERING By Riana Samuel Mysteries of the Human Body What causes bad breath? Bad breath, or halitosis as it is medically known, is an age old problem for almost everyone. 85% of cases are due to bacterial microflora of the mouth producing nasty smelling compounds such as hydrogen sulphide (think rotting eggs) and methyl mercaptan. Studies done on patients with halitosis found the types of bacteria in their mouths differed to those in the control patients. Even though these bacteria do not cause disease, a patient’s poor breath can have social or psychological effects on their health. Even though bacteria are the main cause, there are other factors such as eating or drinking certain foods such as garlic or alcohol, smoking and gastrointestinal or lung disorders. The best thing to do as a preventive measure is good oral hygiene or a suitable mouthwash. What causes body odour? Everyone’s sweat is actually odourless (I’ve tried telling my mum this fact but she doesn’t believe a word). What causes our own unique odour is a mixture of diet, gender, genetics, health, medication, and mood. These factors affect the type of substances that we excrete in our sweat, which are then metabolised by various bacteria on our skin surface. Now this may seem like an outlandish idea to anyone who has had a whiff of clothing worn during any form of physical activity, but our individual odours are actually a way for picking a suitable mate. The MHC class of proteins which are so critical to immunity have an effect on what odours we find attractive. Potential partners with immune systems most different to us will smell more attractive than one who has an immune system which is more similar. For those who want to improve their body odour, not much can be done except improving overall diet and hygiene. Why do pregnant women experience cravings? Pregnancy is one of the most important times in a woman’s life when many important changes are taking place, yet no change is more disconcerting than watching a pregnant woman wolfing down a bowl of ice cream and pickles or some other absurd combination of culinary delights. As to why women crave weird combinations of foods no one knows for sure, but there are a few theories. Firstly, scientists believe the fluctuation of female hormones such as oestrogen and progesterone cause cravings; based on the fact that women can crave foods they had no affinity for prior to pregnancy. The second major theory is that cravings are the body’s way of indicating that there is some nutrient deficiency present, and compensates through craving foods that will correct this deficiency regardless of their combination. There is also some research to suggest that a naturally occurring substance in the body, endogenous opioid peptides (EOPs), modulate our longings for food. Studies on pregnant women show heightened levels of these peptides. Normally, cravings during pregnancy are not harmful however some women do crave items that are not foods and could potentially cause damage. This is medically termed pica, and can include things like dirt, paper or coal. Why do you get a lump in your throat when you’re sad? We all know the feeling, watching a particular sad film or during a wedding when we get a sensation that something is lodged quite firmly in our throat. Scientists have a name for this phenomenon: globus sensation. The globus sensation is an exaggerated awareness of the muscle spasm of the oesophagus. For most of us it is a normal response to emotions such as sadness, panic or anxiety; however for some it can indicate underlying pathology like inflammation due to gastrointestinal reflux or depression. Why do most men go bald with age? Baldness in general is caused by a wide variety of factors, but for the purposes of this question the focus is on the type of hair loss that can reduce grown men to tears: male pattern baldness or androgenetic alopecia. Contrary to popular belief, baldness is actually caused by oversensitivity to circulating male hormones, in particular dihydrotestosterone (DHT). DHT is a powerful sex hormone and promoter of hair growth on the body and face, however it adversely affects hair on the head. This is done by the gradual process of follicular miniaturization, until eventually hair shaft width is so diminished that all that is left is fragile fuzz-like hair or even complete lack of it. There is some dispute as to why baldness actually occurs in an evolutionary sense, although one theory is generally accepted. This theory states that baldness is a sign of enhanced social status and maturity but with reduced physical threat, which could be more appealing to females searching for a long term partner to raise offspring until adulthood. Today baldness is seen as something quite the opposite, and although some men adapt to the change well, there are others for whom there are many social and psychological problems. However baldness will affect all of us, male or female, to some extent so we might as well embrace it!
37 37 PoLITICS Arts & Culture ILLUSTRATION BY DANIELLE NATIVIDAD @dnat ARTICLES BY Anna Zhang Cassie Spry Emily Neilsen Elyse Walton Lisa Healy Chloe Blythman Grace McKinnon Brodie Everist
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