What makes me feel hungry?

Wednesday 22nd July 2009
Submitted by Luis Villazon
Laura Finnegan, Ballinasloe

The vagus nerve sends information about the fullness of the stomach to the hypothalamus in the brain. Hunger is also controlled by hormones, including insulin, leptin, ghrelin and cholecystokinin. Levels of these change according to the levels of various nutrients in the blood and digestive tract.

Why does breathing pure oxygen kill you?
previous qanda Article
What is pins and needles?
next qanda Article
Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Lobsters and other shellfish have harmful bacteria naturally present in their flesh. Once the lobster is dead, these bacteria can rapidly multiply and release toxins that may not be destroyed by...

Astronomer Fred Hoyle was the first to point out that if you could drive a car upwards at 95km/h (60mph), it would only take about an hour to get into space. To get to the Moon would take a little...

Beard hair is quite different to head hair; it is coarser, curlier and doesn't fall out as we get older. Comparatively little work has been done on the genetics of human hair colour, but it is...

This is because it isn’t the pudding or the liquor that is on fire: it is in fact the vapour associated with the alcohol that burns. The flame never actually reaches the pudding itself....

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here