How do tattoos work?

How do tattoos work? I mean, if human skin cells are always shedding and reproducing themselves, how are the pigments of a tattoo able to stay in the skin for so long?


What's TMJ and how can I get some relief?

1) What is TMJ? What kind of doctor handles this problem?

2) I have a rather odd problem. For the past several years, I have noticed that when I open my mouth wide to yawn or take a bite out of a sandwich, the right condyle of my jawbone slips laterally from the temporomandibular joint, making it difficult, and at times, painful, to close my mouth. I basically have to slip the condyle back into the socket; otherwise, it slips in by itself, which is what causes the pain.

Other than being inconvenient, this has not adversely affected me in any way that I can tell, except that I am now careful not to open my mouth completely when I yawn. I am reluctant to see a doctor about this because I cannot reproduce the situation at will, and don't know if the problem can be diagnosed or detected unless the doctor actually sees the condyle slip out.

Also, any time I have gone to Health Services, it seems that whatever the problem, they just send me home with a jar full of ibuprofen. What do you think is wrong? Is this problem serious? Does it deserve immediate attention? What type of doctor would I need to see and could I get a referral from Health Services?


What’s the deal with fats in different types of avocados?

1) What about avocados? I know they don't contain any cholesterol, but they are high in fat so I have avoided them. Now, however, I am reading that the kind of fat they do contain may be useful in lowering cholesterol. Do you have any further information on this?

2) I love avocados and have heard that the different varieties have different health benefits and some are less fattening than others. Please can you tell me about different varieties and which are best.