Tri-3, Wk2, Days 135 & 136, Monday & Tuesday

Darn studying got in the way of blogging yesterday. I got in a pretty good 8 hours of studying, at least with all my material in front of my and up on my computer. I can tell my focusing has gotten better since I've started in school. I kind of miss the girl that used to sit next to me for all my classes - we generally talked daily on "strategizing" on how to take care of everything we needed to get done for school and having someone to talk with in the same boat you're in was a great help.

I wanted to put up a couple pictures today from pathology. One will be of atrophied muscle cells - a nice pictoral representation of "use it or lose it". The other is a picture of liver cells and the damage that can be done to them via the use of acetaminophen, more commonly known as Tylenol. Actually, the cells of the liver are either dead or dying due to using too much Tylenol. I guess the advice here would be to use only when absolutely necessary, if at all.

I checked a couple different online sources (here's one of them, http://www.liverdisease.com/painkillers_hepatitis.html) and it stated small doses are safe and cited 4mg or eight 500mg tablets over a 24 hour period would be safe. Small dose or not, it's still the liver that will deal with the ingestion of any acetaminophen. Interesting picture though, don't you think?

With acetaminophen, we're looking at a chemically induced cell injury which then falls under the subheading of being indirectly cytopathic and is the result of the formation of free radicals during the metabolism of acetaminophen. So, if anyone is taking anti-oxidants then keep in mind that something like Tylenol would be the ANTI-anti-oxidant. ;)

Atrophy is an adaptive response to stress and the reasons for an atrophied muscle could be decreased workload, loss of innervation, diminished blood supply, inadequate nutrition or loss of trohpic stimulation. The teacher gave a neat example of atrophy by comparing it to a car dealership - in difficult economic times, a car dealer may need to discontinue a few models and maybe lay off a few employees but at least the dealership is able to stay alive and continue it's existence. Sometimes cells do that. Cells can throttle back their level of function which, while maybe not optimal, at least they get to stay alive. Also, it should be noted that when things get better, say economic times improve in the case of the car dealership then employees can be called back and new models re-introduced. It's the same way with a cell. This would be an indication that the diminished capacity of the cell is reversible - which is a GREAT thing :)

You could say cells have two options when faced with stress - adapt or die.

Actually, becoming injured would come before death and then the injury is either reversible or irreversible.

Some ways cells adapt are

• atrophy - throttle back size & functional capacity
• hypertrophy - enlarge and (usually) increase functional capacity
• hyperplasia - divide and grow via cell division
• Metaplasia - change into a new type of cell better able to handle the stress

I think it's safe to say that I'm really liking pathology. The metaplasia is particularly fascinating. Cells, metamorphosing into something new to better handle the stress. I'm particularly interesting in the bronchi of the lungs. Normally, those cells are ciliated columnar mucus-secreting epithelium but, under long standing irritation (say, by cigarette smoke) then those cells can change into squamous epithelium which is better able to withstand the smoke. A positive thing is that metaplasia is a reversible adaptation.

I think another phase or adaptation (?!) would be Dysplasia but ...that is generally a change to an aberrant cell or cancer. I guess I better get back to learning the physiology of the lungs - it's getting interesting and physio is a class I'm really going to have to study everyday because we have class everyday with a two hour helping on Wednesdays