Divine or random creation?

 A much more sensitive topic and probably controversial to some people is the complexity of the body and how that came about. Those who believe in the letter of the Bible and creationism believe that God created life and therefore every structure and function therein. 

The staggering number of components and functions that are interrelated is staggering. Take, for instance, epithelium. There is the apical-basal polarity (crudely, that's the top and bottom of, for instance, skin tissue) but then there's also the basal lamina which is a noncellular sheet just beneath / outside of the basal surface which acts as a border crossing for molecules - it determines what gets into the epithelium from surrounding connective tissues. 

Then there are the fluids that connect or lubricate. 

And so on. 

Is it divinely created - every single atom placed in perfect order to create each molecule which were then placed in perfect order in combinations to create each cell (and all of the components of each cell, which is an incredibly complex body in and of itself) and then each cell placed and ordered into tissues and each tissue placed and ordered into each organ and the organs placed and ordered into systems which together function as the being? Did God do that?

Or, did billions of years of random evolution go from one organism to another, slowly mutating due to environmental circumstances to grow into all of these components, failing and succeeding zillions of times to end up as the wildly diverse population of humans that we are today? 

Tissue study: making epithelial flashcards

 I'm currently studying about tissues. A classmate asked me about my methods of studying. I mentioned flashcards and pneumonic devices. Another thing that I just thought of as I was creating a flashcard was opposites.

For example, there are 6 main functions of epithelium:

1. Protection
2. Absorption
3. Filtration
4. Excretion
5. Secretion
6. Sensory reception

However, not only for memorization, but understaning the funcions better is to group them. The easiest pairs to make are absorption & filtration and excretion & secretion. 

While epithelial tissues can absorb beneficial nutrients, they also filter out bad stuff (we hope.)

While epithelial tissues excrete waste, they also secrete beneficial fluids.

I also think that protection and sensory reception can be grouped together. After all, while protection can be a barrier to harmful elements, those outside elements can be sensed to trigger a response from the body (hot stove -> pull hand away.) 

So maybe I'll reorder them on my flashcard:

1. Protection
2. Sensory reception
3. Absorption
4. Filtration
5. Excretion
6. Secretion

***

In making flashcards, one of hte hardest things to do is decide what goes on a flashcard. For example, I'm in the first section of the topic and already have 11 cards because, for example, there are different kinds of epithelia, then each type of epithelia has its own composition and characteristics, and those components have THEIR OWN components and characteristics. 

Receptors, Feedback, and Effectors

 I like that my Anatomy prof is constantly phrasing her questions as critical thinking questions. For example, what does oxygen do for the body? Someone answered that it helps keep us alive. Yes, but how? I thought for a sec and recalled that it is an integral part in respiration (creates ATP) and deals with the exchange of electrons and protons to help maintain homeostasis.

Feedback is interesting - negative feedback vs positive feedback. It's part of maintaining homeostasis. There is the receptor, the control center, and the effector. The control center determines the set point or range for a set point of a variable (such as temperature.) The receptor monitors the environment and responds to stimuli by sending signals for needed changes. The control center receives the input from the receptor and sends output to the effector on what to do.

Negative vs positive feedback cannot be thought of as good vs bad. It is simply the type of process the body uses to keep itself in balance. Negative feedback goes in the opposite direction as stimulus and is more common, like shivering to warm up or sweating to cool down. Positive feedback responds in the same direction as the stimulus, like platelets coming to plug a cut.

Here's something cool - do you know what platelets are? They're the things sent by blood that clot a cut. Platelets have receptors that activate when they attach and send signals for more platelets to come and attach. 

Q: do they also send signals for the healing chemicals?

A: platelets send signals for the growth signals / hormones - growth factor. Once the wound is healed, then signals are sent that break down the platelets.

Other positive feedback: labor contractions get stronger and stronger. If it was a negative feedback, the body would try to stop that process.

Temperature signals are sent to the hypothalamus section of the brain.

We're talking about positive feedback and thinking about birth when the following quesion occurred to me: if gestation is typically 40 weeks, why are babies that have gone through the same duration of gestation different sizes? If cell division is cell division, then why wouldn't a smaller baby be born just at an earlier date? Shouldn't all babies go through the same growth within the same time frame?

Modern Learning Platforms

 One of the best things about modern education is the online learning tools. Both McGraw-Hill and Pearson have tools that allow you to use drag and drop to rank or label. Even better is "check my work." 

For me, getting a problem wrong is annoying (and sometimes infuriating,) but knowing why I got something wrong dampens the blow. And that's what the homework provides: instant feedback on problem solving. 

Old / traditional way: do homework. Turn in homework. Teacher grades homework. Teacher gives homework back days or weeks later. 

New way: do homework getting constant feedback about my progress.

I can't find a way to make the old way better. Can you?

***

Oh, Pearson calls these "dynamic study modules." I forgot that you can not only answer questions and get feedback, but you can rank as either 

I'm sure

I think so

Not sure

I don't know yet

It also then tells you were to find the answers or where your weaknesses are and where to focus your studying. 

McGraw-Hill also would create practice tests for me, so hopefully Pearson's app will do that, too.