What controls your heartbeat and blood pressure?
Physiological feedback pathways involving nerves and hormones control the functions of important body organs such as the heart and blood vessels.
How does the human body cope in extreme environments, such as climbing Mt Everest or deep sea diving?
There is enough oxygen to supply the human body in our usual environment. But oxygen is in short supply at the top of Mt Everest, while the high pressures experienced during deep sea diving are at the other extreme. However, to deliver oxygen in the right amounts your body can adjust to higher or lower levels. For example, elite athletes who are required to perform at altitudes higher than they normally do will usually spend time acclimatising to the new environment before competing.
How does loud sound cause deafness?
Our physical experience of the world around us is mediated by special sensory organs in the body. The cochlea of our ear is specialised for sensitive detection of sound wave energy, but delicate cells in the cochlea can be damaged by too much energy.
Is eating too much fat really bad for you?
Fat is a normal and key component of every cell in our body, so it is essential to maintain a certain level of fat in the body to remain healthy. The problem with eating too much fat is that you build up too much adipose tissue. This tissue secretes a hormone called leptin, which eventually damages many of the body's important control mechanisms.