Simple science shorts #1

Again I would like to explore a different route. As I haven’t posted in a while I thought I would lump together some ideas I have had over the past few weeks that I feel may not be worth an entire blog on their own. If you would like some more short questions answered send me a message and I could include them if I do something along these lines again! Enjoy!

Why does your stomach rumble when you are hungry?

                A very common occurrence during the interdigestive phase. It has been several hours since your last meal and suddenly everyone around you becomes very aware that you are hungry. The rumble of your stomach associated hunger is a series of convulsions known as the migrating motility complex (MMC). The MMC triggers peristaltic waves (muscular waves, the same as in your throat for swallowing) in an attempt to transport indigestible materials such as bone past the ileocecal sphincter and into the colon. So in essence, your stomach starts attempting to suck in other parts of your body to eat.

What makes your eye twitch?

                Unwelcomed spasms of the eyelid come and go without much thought despite them being mildly annoying. Known as “myokymia” to doctors, an eye twitch is simply rippling muscle contrations caused by a variety of simple triggers such as: tiredness, stress, caffeine, allergies, dry eyes, alcohol consumption or caused by an irritant. Generally (almost always), eye twitching is a benign condition (meaning harmless) however in some cases it can be an indication of neurological conditions. Blepharospasm is a CNS disorder sometimes associated with an eye twitch however the cause is not yet known.

Heard of a Demodex?

                Based on their abundance you definitely should have but if you are squeamish I recommend skipping this section and move on…..

Demodex are arachnids called eyebrow mites and they are considered one of the most commonly occurring human parasites. Up to 90% of people have them and they are very contagious but at only 0.3mm long, you won’t be seeing any without a microscope. The 2 species that might be found within your hair follicles or sebaceous glands are Demodex folliculorum and D. brevis but do not worry, they will not harm you in any way. They simply feed off of skin cells and oils which can actually be beneficial by preventing waste build up on the skin surface.

Demodex folliculorum

What causes “butterflies” when you’re nervous?

                Some of you may now be experiencing this due to your new found knowledge about Demodex. Interestingly, your digestive system is actually closely linked to your thoughts and emotions. When you are faced with a nerve-wracking situation the body undergoes its “fight-or-flight” response which includes increase of heart rate, blood pressure and breathing rate. Stimulation of adrenal glands also releases adrenaline and cortisol whilst muscle contraction makes the body more alert. The rush of adrenaline temporarily halts digestion enabling energy and oxygenated blood to be utilised in the necessary working muscles. Sensitive muscles surrounding the stomach also contract. The combination of muscle contraction and ceased digestion gives you that fluttery feeling when you are racked with nerves or fear.

Which came first the chicken or the egg?

                The egg….Dinosaurs laid eggs…

How accurate is counting a trees rings to determine its age?

               

                Dendrochronology is the analysis of growth rings and throughout school we have always been told you can determine how old a tree is by simply counting the rings when you cut its trunk in half. Well this is actually completely true, but the age of the tree is not all you can find out from a cross section of the trunk. Growth rings are the result of recent growth in the vascular cambium which is a layer near the tree bark known as a lateral meristem. There is a visible ring because of variation in growth speed through certain seasons of the year. The inner portion of the growth ring is formed during the early stages of the growing season. Then, under the optimum conditions, rapid growth produces less dense and differently coloured wood followed by the end of season, dense wood giving the distinctive ring formation. The rings can vary dependant on the growing conditions. A wide ring will occur when there is adequate moisture and a long growing season whereas a drought year causes a narrow ring to form. This can however cause confusion as mid-summer droughts can result in “missing rings” or several to form in any given year. To a skilled dendrochronologist however, this is merely an indication of seasonal shifts and the trees age can still be identified accurately.

Note the lighter, less dense rings indicating the rapid growing season. You can also see the variation in size indicating optimal and poor growing conditions.