Adventures in Neuroscience could never be more exciting. Well, maybe a little.
Wednesday, September 26, 2007
First day of class
Just got out of my first class, NEUBEH 501A: Introduction to Neurobiology. Based on the syllabus and the first lecture; it looks like a lot of the same old, same old... but I'm sure I'll regret having said that.
After we got through the standard first class period stuff, the rest of the lecture worked its way around one simple topic:
Neurons are just like other cells... but different.
Theyre the same in that they have all of the standard cell paraphernalia and do all of the standard cell things. They have a full complement of organelles in the soma, they homeostatically regulate their living conditions, all that.
But they're different both because they have specialized functions and because the specializations lead to special needs. They need to be exceptionally long (extreme example: some sensory neurons in the dorsal root ganglion need to carry sensory information from your toes to the somatosensory cortex in your brain; those can easily top 2 meters in us tall folk, and then think about the giraffe!); but the extreme length of these processes leads to a fundamential specialized need: the need to ship proteins and assorted cell products from the soma where they are manufactured to one end or the other of your body. Neurons are also extremely polarized due to their need for fast electric signaling, which is also required for their ability to rapidly exocytose materials (exocytosis = ejecting material from a cell). In addition, neurons have an extraordinarily long life cycle: although some neurons can be replaced during the course of a human life time, they are definitely in the minority.
There was then some small discussion of the specializations underlying different types of neurons, but my battery is about to die so I'll leave it at that for now.