hello, folksies! what a lovely day it is in pittsburgh … balmy, sunny, full of promise and potential. this morning has been fairly peppered with blessings. for one thing, i caught the bus five minutes early (and the blessing in that is that i was there to catch it, because had i come at the normal time, i’d have been stranded). then i spent the commute alternately re-reading my health communications assignment and playing peek-a-boo with the big-eyed baby in the seat ahead of me. having arrived at duquesne a whole half hour before class, i trotted over to assumption hall for extra perk! saw old friends, had a cinnamon bun, put creamer in my toffee caramel coffee (which i’d brewed through a plastic funnel earlier… just like daddy…) and in general felt rejuvenated. which isn’t a bad thing to feel at half-seven in the morning.

well, anatomy lecture was a scintillating discourse on skeletal muscle tissue. two hours and we just scratched the surface! dr. clemente described the muscle contraction mechanism as “an extremely efficient, elegant design” — which is an understatement. i wonder if he had a Designer in mind. anyway, this is so cool! there’s a little “factory” in each of your cells called the smooth endoplasmic reticulum, and in muscle cells it specifically secretes, stores, and regulates calcium. squished in right next to that is a narrow tube — the T-tubule — that’s connected to the nerves. and the muscle cells themselves are composed of long columns called myofibrils with actin and myosin filaments inside. technically, the actin filaments have three parts: the F-actin filament, the tropomyosin, and the troponin. F-actin’s a long chain of spherical subunits and tropomyosin winds around it, and troponin is a three-unit complex that just chills at various points along those chains. the important thing about F-actin is that each subunit has a little notch that hooks onto the other filament, myosin, to make the muscle contract, but when it’s all wound up into filaments, that notch faces inward so the muscle rests. and arranged in a spiral along the length of the entire myosin chain are little heads that look like golf clubs, which normally just stick out straight.

so what happens when your brain says, “jump!”? the brain sends an electrical signal to the nerve connected to the T-tubule. when it gets to the T-tubule, the smooth endoplasmic reticulum lets loose a barrage of calcium. calcium is drawn like a magnet to one side of the troponin complex, and as soon as it attaches, troponin flips the actin-tropomyosin rope open, like a key opening a lock, and lo and behold! now those notches are exposed and the myosin filaments can grab on to them. as soon as that happens, the heads on the myosin strain forward, starting from one end and moving down in a spiral, to connect with those notches, and that makes the actin filament contract. and up you go! and you go up smoothly, because the heads are arranged spirally so the impulse moves down the muscle quickly instead of stage by stage. isn’t God fantastic? 

then, in anatomy lab, we finished learning the three pages of points, processes, tubercles, foramina, and sutures on the skull. next time you say your sinuses are congested, you should specify, because there are about seven hundred kinds of sinuses. (personally i’m a fan of the sphenoid.) and jon baker almost died. we were standing there scrutinizing the posterior clinoid processes when he went white and said “i feel really dizzy”. so we sat him down, and then took him over to the PA lab so he could lie down on one of the exam tables, and fed him a cereal bar, and he’s been ok ever since. it’s pretty strange though…

lunch was fun, since we got to see johnny (who’s transfered to pitt and broken all of our hearts simultaneously). that boy… and after my health communications class (which wasn’t particularly noteworthy), i bought two books for three dollars each which is enough to make my whole entire day!

and now it’s off to drum the krebs cycle into my head. oh, but soon – at least, as soon as i take them – i’ll put up pictures of the regent square house! it is indeed a happy home!

from my devotional reading this morning:

My child, thou mayest not measure out thine offering unto me by what others have done or left undone; but be it thine to seek out, even to the last moment of thine earthly life, what is the utmost height of pure devotion to which I have called thine own self. Remember that, if thou fall short of this, each time thou utterest in prayer the words, “Hallowed be Thy name, Thy kingdom come,” thou dost most fearfully condemn thyself, for is it not a mockery to ask for that thou wilt not seek to promote even unto the uttermost, wtihin the narrow compass of thine own heart and spirit?

-from The Divine Master