TSR Med Students' Society (TSR Meds)

Comparative neuroanatomists cite decussations as an example of the continued exploitation of a structural feature that helped our lowly ancestors escape from predators more efficiently than their even more lowly competitors.

Natural selection would not allow the loss of a decussating pathway if this were an advantage in a world full of other edible animals with non-decussating neural connections.

In order to have left and right sides an animal must have different dorsal and ventral surfaces. The struggle for survival is supposed to have been among animals that lived where "dorsal" and "ventral" were significantly related to he surroundings (on the ocean floor,in shallow water, or on land).

Even the most primitive nervous systems include motor and sensory neurons.

A potentially fatal stimulus should evoke a movement of withdrawal, so that the attacked individual may survive and reproduce itself. The animal is more likely to escape by moving away from the assaulted side, especially if the predator is not smart enough to predict such a response. The fastest neuronal circuit for stimulating withdrawal to the other side of the midline is a monosynaptic reflex: a sensory neuron has an axon that crosses the midline and contacts motor neurons that make nearby muscle fibers contract. Such an arrangement makes a worm-like creature bend away from the attacked side.

It may be significant that even in man the midline is crossed at a more caudal (presumably more primitive) level in the pathway for pain than in the pathway for discriminative sensations.

These evolutionary speculations suggest that it is generally advantageous to have neurons capable of sending their axons across the midline.

You'll all be hooked soon enough

my practical partner is very pretty.

Always a bonus

Bump!

Someone must have some gossip!!!!

Of course I do, but it's not fit for sharing with the world

Of course I do, but it's not fit for sharing with the world

even better then..!

so, progress status - 2 exams down - 5 to go. used fluffy's amazing "myriad" word in 2 essays, hopefully that will dazzle them.

Go on.... Go on, go on, go on!!!!!!

Hehe, the rest of Clare knows Bad Helen...

Is baby bf's birthday on Friday, what do I do/get him?

A bib?

Helen's been raiding the secondary schools !

Helen's been raiding the secondary schools !

Hehe, the rest of Clare knows Bad Helen...

Is baby bf's birthday on Friday, what do I do/get him?

Ooh, a new boyfriend Helen??! Is this the one you mentioned going on a blind date with a while ago?? Didn't realise it had progressed how exciting!!
How about paying for something fun for the two of you to do together??depending how adventurous (and rich) you are, could be anything from bowling to iceskating to paintballing to skydiving...would be different and interesting