Ask a Physiologist

Physiology is the science of how humans and other animals function in an integrated way and is the basis for many biological and clinical sciences.

School students and members of the public can submit a question about physiology to The Society using the form opposite. Questions will be answered by a scientist and posted below.

Please note we cannot answer any medical queries or questions related to school homework or university assignments.

Is there a way to precisely detect the age of a human body? (Maxine, age 17)
On one level, yes, more precisely than for any other organism.  This is because, uniquely, you can ask a person for their date of birth, which is one of the first things that a doctor will ask, because it is vital for providing a context for...
Why do I get angry over the smallest things in life and is there an ‘anger gene’ or something in the brain that triggers this? (Tomas, age 19)
Anger is a normal human emotion, experienced by everyone at one time or another.  Generally, we feel anger when something we want is blocked by something that is out of our control. Although it would be oversimplifying things to say that there...
Why does your stomach rumble when you are hungry? (Alison, age 17)
The rumbling sounds are known as borborygmi, and they actually emanate from the small intestine as well as the stomach.  They occur when the gut muscles contract and vigorously move around the contents – food, liquid and especially gas inside...
Where and how is memory stored? (Kay, age 17)
This is one of the ‘big’ questions for which we do not yet have a complete answer.  The human brain contains upwards of 100 billion neurones (nerve cells), which form a network that continuously sends and receives signals, then processes them...
Why are our fingers different lengths? (Alistair, age 18)
As there are a lot of fingers, I will concentrate on the length of the index finger (the one next to the thumb) relative to the ring finger, as men have an index finger shorter than the ring finger.  However, the relative lengths of these two...
Why have humans lost body hair as opposed to keeping it as a method of keeping warm? (Mark, age 17)
Most mammals including primates have body hair and one of its functions is as a defence against cold.  Humans do have some body hair, notably on the scalp, perhaps to protect from radiant energy, and adults have pubic and axillary hair.  ...
How does an ostrich know what it is doing when its eyes are bigger than its brain? (Amber, age 11)
Ostrich eyes are indeed large (it is the biggest bird eye and even larger than that of many large mammals), and bigger than their brains but this does not make them stupid, however. it is not a case of an undersized brain but rather of oversized...
Why do humans need to sleep? (Conor, age 17)
After many decades of research, there is still much debate about the function of sleep.  Everyone would acknowledge that a good night’s sleep makes you feel more alert, energetic and better able to function.  Lack of sleep has clear...
If you imagine the world was made and ended in a day, how much of the day would we take up? (Amelia, age 11)
The earth is around 4.54 billion years old (4,540,000,000 years) and modern human species have been around for about 300,000 years, and even less if you include only our subspecies Homo sapiens sapiens (very modern humans).  So if the history...
Why do we have both burping and farting? (Robin, age 11)
Gases emitted from burping and farting are different in origin.  Burping, or eructation, to give it its medical name, is simply the escape of air from the stomach.  When we eat or drink, we swallow air as well as food or liquid and an...
Why do people hiccup? (Jamie, age 11)
A hiccup occurs as a result of a sudden brief, often violent, involuntary contraction of the diaphragm, and the other muscles used when breathing in.  Physiologists have speculated that there could be a ‘hiccup-generating centre’ leading to...
Is it true that girls have more taste buds than boys and, if so, why? (Josh, age 11)
Some people are ‘supertasters,’ some are ‘regular tasters’ and others are ‘non-tasters’ based on their ability to taste specific bitter substances (the chemical name of one of them is n-propyl thiouracil or n-PROP for short).  Some people do...
How come our brains are so powerful? (Anna and Connor, age 11)
The power of the human brain stems from its incredible complexity.  Indeed, the human brain is probably the most complex thing on planet Earth.  Within the 1.4 kg adult human brain, there are 100 billion neurones.  These neurones...
I know that our brain tells our body what to do, but how does the brain know? (George, age 11)
There are lots of answers to this question! First of all, many of the nerves in your body outside your brain carry information about what is going on back to the brain.  There are your ‘special senses’ (vision, hearing etc.); there is sensing...
Why do men have beards but women do not? (Lewis, age 11), Why do we have armpit hair? (Chris, age 14) & Why do men have facial hair? (Oliver, age 14)
Men and women do sometimes look quite different, don’t they?  The first answer to this question is about the development of ‘girls and boys’ into ‘women and men’.  And it can be explained by what goes on around the time of puberty, in the...
How many times do you blink in an hour and why do we blink? (Alex, age 11)
This is a very good question but it does not have a simple answer because blink rate in humans varies tremendously – from 2 to 50 blinks per minute depending on the circumstances.  For example, if you are concentrating very hard on reading...
Why does a rabbit twitch its nose? (Hannah, age 11)
It is true, the twitch, twitch of a rabbit’s nose is a very obvious characteristic, and very important to its survival.  Not only does it draw air in to fill its lungs and breathe, in the same way as we do, but it also helps the rabbit detect...
How does muscular dystrophy occur and how can we help prevent or slow down the process and is there any possible cure that could occur in future? (Thomas, age 17)
Muscular dystrophy (MD) is an inherited condition in which the muscle fibres are particularly vulnerable to damage associated with activity.  Over time, this leads to muscle wasting, formation of scar tissue and loss of function. ...
Why can’t you tickle yourself? (Chloe, age 17; Flora, age 14; Phoebe, age 12)
The short answer is that your brain already knows how it will feel (because it is you doing it – your brain knows this, since it ‘told’ your body to do it!)  So the sensations the tickling produces (the ‘sensory feedback’, as the touch and...
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