November 04, 2006

Suffering from serious sleeplessness. Decided to read something interesting.

PAIN

Pain is an unpleasant feeling which may be associated with actual or potential tissue damage and which may have physical and emotional components. According to the International Association for the Study of Pain (IASP), one should distinguish between pain and nociception.

Despite its unpleasantness, pain is an important part of the existence of humans and other animals; in fact, it is vital to survival. Pain encourages an organism to disengage from the noxious stimulus associated with the pain. Preliminary pain can serve to indicate that an injury is imminent, such as the ache from a soon-to-be-broken bone. Pain may also promote the healing process, since most organisms will protect an injured region in order to avoid further pain. People born with congenital insensitivity to pain usually have short life spans, and suffer numerous ailments such as broken bones, bed sores, and chronic infection.

Interestingly, the brain itself is devoid of nociceptive tissue, and hence cannot experience pain. Thus, a headache is not due to stimulation of pain fibers in the brain itself. Rather, the membrane surrounding the brain and spinal cord, called the dura mater, is innervated with pain receptors, and stimulation of these dural nociceptors (pain receptors) is thought to be involved to some extent in producing headache pain. Some evolutionary biologists have speculated that this lack of nociceptive tissue in the brain might be because any injury of sufficient magnitude to cause pain in the brain has a sufficiently high probability of being fatal that development of nociceptive tissue therein would have little to no survival benefit.


FEAR

It's dark out, and you're home alone. The house is quiet other than the sound of the show you're watching on TV. You see it and hear it at the same time: The front door is suddenly thrown against the door frame.

Your breathing speeds up. Your heart races. Your muscles tighten.

A split second later, you know it's the wind. No one is trying to get into your home.

For a split second, you were so afraid that you reacted as if your life were in danger, your body initiating the fight-or-flight response that is critical to any animal's survival. But really, there was no danger at all. What happened to cause such an intense reaction? What exactly is fear?

Fear is a chain reaction in the brain that starts with a stressful stimulus and ends with the release of chemicals that cause a racing heart, fast breathing and energized muscles, among other things, also known as the fight-or-flight response. The stimulus could be a spider, a knife at your throat, an auditorium full of people waiting for you to speak or the sudden thud of your front door against the door frame.

The brain is a profoundly complex organ. More than 100 billion nerve cells comprise an intricate network of communications that is the starting point of everything we sense, think and do. Some of these communications lead to conscious thought and action, while others produce autonomic responses. The fear response is almost entirely autonomic: We don't consciously trigger it or even know what's going on until it has run its course.

All of these physical responses are intended to help you survive a dangerous situation by preparing you to either run for your life or fight for your life (thus the term "fight or flight"). Fear -- and the fight-or-flight response in particular -- is an instinct that every animal possesses.



Still not feeling sleepy. Damn whats wrong with me - I need sleep!

Up Next: Happy Tree Friends

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