It is important for everyone to be aware of the distinctions that Anita has made. If you request a necropsy, then that is what you will get. Most vets do not have the ability to process histopathologies themselves, so they often have to be sent off. There are several labs across the country that process tissue samples in this manner. Most veterinary offices have the collection jars and formalin on hand for the collection of histopathology samples.
histopathology is necessary when there are no obvious answers upon a gross necropsy. For example, if the glider died of sepsis, there might not be any visible evidence.
I suggest, for the sake of research, that you always have a necropsy with histopathology of the 5 major organs at a minimum (heart, lungs, liver, kidney and brain).
It is important that you have this conversation with your vet BEFORE you need a necropsy. My vet in Amarillo will not do a necropsy. Recently, I would have been in a pickle if I had not known this beforehand. My vet in Tulsa WILL do one and will let me watch if I like.
Most vets will not look at the brain. The process of removing the brain might mean that your baby cannot be returned to you in a semi-normal looking condition.
Please know that if you do have your glider sent to a lab for necropsy, you will not get the body back for burial, but you can request that the body be cremated after the exam and that the ashes be returned to you. Each individual lab is different.
These are things that you should know before you NEED to know them. It is difficult to think clearly and to ask all the questions you need to or want to ask when in a state of grief. Please approach your vet now and begin this discussion.