both those articles fail to mention the issue we have already broached here....
when your temperature starts to drop, your vascular system contracts and slows/restricts the blood supply to the extremities as these, while rather important, can be sacrificed to ensure the essientials of the body continue to recieve warm oxygenated blood. in addition, if this process didnt occur, your blood would actively draw heat away from your core speeding up the loss of heat. this process is complicit in the issue of frost bite, its not just about the cold, as the cold could be offset by constant suply of warm blood... so food, core wamrth and preservation heat by insulation elsewhere will slow the progress of frost bite
re your head, as mentioned it is one of those essiential organs that unlike a foot or arm, you cannot live without. the blood supply doesnt, at first reduce to the brain the same way as it does to the limbs... though as the core temp drops, the same process will apply... hence the confusional state, slurring of words, lack of co-ordination.... all caused by a reduction of the blood supply to the brain.
the body is an amazing thing and will change and adapt as rapidly as it can to prolong and preserve its existence. of course there will come a point when the blood supply to the brain slows to such an extent you become comatose.. you are then completely unable to withdraw to safety and night night irene... but your body is still trying to save itself by doing that,, withdrawing the last of the heat and warm blood to the core to feed the most important organ, the heart (ok yes, you cant live without a brain either, but your heart can still pump warm blood round your body as long as it still has some coming to it.. head or not!)
so as i said, warm core, with a warm head gives the best chance of maintianing a good core temp. while you loose lots through your head, i dont know how much, but i do know you will continue to loose heat through your head long after your extremities have turned off the radiator vales
btw, i will happily question the "surgeon" on yahoo who states you will bleed out from any surface vascular bleed. does he not know about the clotting process that our blood cells and fibrin very convientiantly undertake for us? if that didnt happen, we would bleed out from any wound. vascular blood is not under pressure unlike arteial and the lack of goss muscle in the scap further slows the vascular ebb and flow. head wounds just look bad, a combination of lots of capillaries, tight skin and hair combined with the different type of soft tissues in the scalp that dont lend themselves to constricting the veins (hence the lack of vasoconstriction in the early stages of the cold to an extent too) as you find in more muscular parts of the body.... direct pressure to a scalp wound mimics the action of vasoconstriction, slows the flow and allows clotting to take place. though most scalp wounds over half inch will will require suturing to close them up.....
i am not a doctor, nor should this be a substitute for proper (face to face rather than the interweb) medical advice or treatment but i do have a day to day working knowledge of anatomy and physiology, though mostly from the neck up and as it goes, a bit of hepatology, immunology and the vascular system