I wouldn't call it a "trip" perse. But I have just returned from a year in Africa. Before that I worked in Central America, and also in other areas of Africa. But I can not speak for everywhere, I can only speak from my experience. Others, no doubt, have had different experiences.
Nursing in developing areas. The training can be quite good- but the nurses tend not to have anything (supplies wise) to practice on. They give a lot of care as students. In fact, in Liberia, most students as a requirement must deliver (not attend the delivery, but do the delivery) of at least 20 infants before they can graduate... In other areas, no one has any medical training. In the Southern part of Sudan all the medical staff we hired were trained by us. The big requirement was that the candidate could read/understand/speak English, so we could communicate. I did a teaching for the staff one day and found NONE of them could show me where the stomach was, they had no idea. So training there is at a low level, but very satisfying as these guys have no bad habits to begin with.
Healthcare in general: In some developing countries good healthcare can be obtained, at a price. For people with money, health care is available (This may mean that they take a trip to a neighboring country, but they can get it). For those that do not, it is not available. In countries with instability, a lot of healthcare is given by aid organizations, which can produce dependency and duplication of aid....Suzanne mentions that children are often not vaccinated. If there are lots of aid groups- some children are vaccinated multiple times for the same childhood illnesses. This is not supposed to be harmful- but it is a waste of resources. Duplication of services can be a big concern in these settings.
Public Health concerns are paramount- as disease caused by a lack of clean water/sanitation/etc is very common (think Cholera and Typhoid, hepatitis A). So things like a decent working sewer, clean safe water, save more lives than many drugs.
Childhood diseases such as measles, polio are common as is tuberculosis. Tetanus, both newborn and adult were fairly common as well. Chronic diseases, such as diabetes, tend to be killers in these settings.
As far as how it was: This type of work is very difficult. The climate is different (In Sudan it was about 120 degrees everyday, in Nigeria the Harmattan winds were strong for most of my mission, making it hard to not eat dirt literally.), the food can be a bit strange- making you sick, and the living conditions may not be to your liking (Spiders, Snakes, etc). Working with staff is usually fun, but change has to be introduced very slowly. (The nurses I worked in one place had this idea to put the entire stylet into the vein when starting IV's, they couldn't figure out why the veins blew so many times...but it was also hard to get them to try something different,) In addition, the staff have all the problems of regular staff (not being on time, making drug errors, etc) plus the problems of facing poverty themselves or facing war depending on where you are. The patients are generally about like American patients. They do not thank you over and over again, and they are not "just so greatful" as many people would like to think. Some patients will thank you, some won't. It can be a bit different if you go on a two week trip and do a bunch of surgery and then leave, but when you are in that situation day in and day out, and end up saying "no" to a lot of people (who are asking for things you don't/can't do) , it starts to be a lot like any other job, really good days and really bad ones. The bad days are especially bad- it is hard to watch people die from a lack of a dialysis machine, or a child die because there is no blood and the hb is reading less than 3... It is especially hard to explain to the parent or wife why we couldn't save their family member... especially if one does this 3-4 times daily it can get wearing, and it does not feel rewarding in the least in those moments. Good moments do occur, but not exactly in the same porportion...
OK, That's waaaay too much and I am sure someone will disagree with me on many points- after all this isn't a research paper, its off the top of my head. But I think it probably will be useful for your class.