Friday, February 3, 2017

Teaching Demo Link

Click here to get to the YouTube videos that were made of me teaching osmosis & diffusion and GFR.

Maintaining Boundaries part 1 - Intro,The Epidermis & the Dermis

Close your eyes for a minute and pretend you've just bought a gorgeous property.  This lovely land that you now own is set smack in the middle of a public park.  The park itself is beautiful as well, and there is no way of telling when you're on park land vs. private property at the time of purchase.

So what's the first thing you do after you've invested this spot?  Build a fence, right?  Create something to keep the public (well meaning as they might be) out of your private space.  You want something that tells people they are about to cross onto private property, not public land.

What kind of a fence do you build?  Well, that depends - If you want to keep everything out, you build one kind of fence.  If you want to let people see in, but not get in, it's another kind.  Do you want sunlight, wind, fresh air, rain to get to the landscaping?  If you want to completely isolate your property, maybe you build metal dome over it all.  Obviously, the type of fence or barrier you create will depend on how it is used.  If you're planning on building structures or a home on your new property, you'll have to go through the same considerations – what type of walls and barriers do you want to have around each individual part of your property.

Do you want to keep everyone out of everything?  Maybe there are just certain areas of the house that are more private than others.  Maybe you have cats that are indoor cats, they can't go outside.  The dogs, however, can go inside or outside, as long as they are within the property limits.  And what about guests?  Do you want guests to visit?  Long term or short term?  Where can they go and stay in the house?  Is there any areas of the house that are for you alone?

How are you going to decide who can come in and who can't?  What securities have to be in place to make those choices a reality?  Will there be keys that only you have?  How about workers, and people coming to help out at the house – will they have access?   And maybe you want to have extra security measures to deter those you don't want to have access – moats, walls, boiling hot oil to pour on invaders.

Obviously, I'm using the house and property analogy to lead into talking about how our bodies maintain boundaries.  Just like the property, the first thing that we do is build a wall if we want a separation of space.  Every cell in your body is built with a fence around it – the cell membrane (aka the plasma membrane) is that outer layer.  That membrane keeps the outside out and the inside in.  The type of doors and locks and security that barrier contains depends upon the type of cell we are talking about.  Muscle cells are built differently from the cells that line the small intestine, which are in turn different from the cells that are found in your bones.  We'll talk more about how the cell membrane is made up and why it matters when we talk about responsiveness as well as metabolism, and reproduction.  But for now, know that the make up of the cell membrane is the primary thing that dictates how that cell behaves and who and what it communicates with.

But let's zoom out a little bit and look at the big picture – the boundary of the entire organism, in this case, humans is primarily the integument, or the skin.  The respiratory system, digestive system, circulatory system, immune system and nervous systems all play roles, too.  

The many layers of the integument form a relatively solid barrier which must be crossed if something is to enter the interior of the body.  Look at the structure of our skin for a moment.  There are two parts to the skin, and there is another part that is typically included with the skin structure, even though it is not officially considered a part of the integument.  The two parts are the dermis (internal) and epidermis (superficial).  We'll talk briefly about the structure of each of them. 

The epidermis has many layers, or strata, of cells – there are 4 or 5 strata, depending upon which area of the body you're looking at.  Over most of the body, there are four layers, and where we have thick skin, there are five layers.   (That thick skin is found on the palms your hands and the soles of your feet – areas where you need extra protection)

Remember back in module 1 when I said that even at a microscopic level, form follows function?  (Wolff's law).  Under a microscope, the outermost strata contain flat cells, which are dead bags of a protein called keratin.  The innermost strata (stratum germinativum or stratum basale) is where these cells form (germinate), and as they move through their lives they are pushed more and more superficially, changing from cells that are more cubed (cuboidal) into flat bags of keratin that resemble scales.  There are a few cell types found here – the keratinocytes are the cells whose journey we will follow from deep to superficial as we move towards the surface of the skin.  Melanocytes – are the cells that secrete melanin – a dark pigment that gives color to the skin – the more melanocytes, and thus the more melanin your skin has, the darker it will be.  Epidermal dedritic cells help to activate immunity when necessary, and merkel's discs are connected to nerves and bring sensations of light touch into the central nervous system. 

Moving superficially, the next layer is called the stratum spinosum.  Just like it sounds, stratum spinosum means spiny layer.  It's called that because of how it looks under a microscope.  When cells are fixed for viewing on a slide, they lose water, which causes them to shrink slightly.  However, the cells in this layer have gap junctions which cause parts of them to stay stuck together.  When the areas between the stuck parts shrink, we're left with cells that have a spiny appearance.  (How well you can see this phenomenon will depend on the quality of your microscope.  Don't worry if you can't see it, just know that's how it got named!)  In this layer, the keratinocytes are starting to produce a substance called cytokeratin, which will eventually become that protective substance called keratin.  Cells in this layer are still mostly cuboidal in shape, and are still living. 

The next layer out (or superfically) is the stratum granulosum (granular layer) – called this because when skin is stained under a microscope, dots (graininess) can be seen which are what hold the keratin molecules together.   It is in this layer of the skin that the cells are dying – they lose their organelles here, as well as produce what are called lamellar granules, which eventually fuse with the cell membrane, release their contents into the extracellular space, and helps to form a waterproof barrier within the skin.

Thick skin has an extra layer which is found next when present – just underneath the outermost layer – called the stratum lucidum.  And it serves to provide an extra layer of protection for the areas that are most in need of it.  Thick skin is found on the soles of our feet, and the palms of our hands.  Two “high traffic” areas in need of as much protection as possible as we move through life.  The stratum lucidum is composed of 3-5 layers of dead cells which contain a form of keratin called eleidin.  It's name (clear layer) comes from the fact that it appears translucent under a microscope. 

The outermost strata, the stratum corneum, is several cell layers thick (can be up to 25 cell layers), and serves to protect the body physically and chemically (we'll talk more about those different ways in a bit).  If your arm rubs against a wall as you're walking down the hallway, most of the time, you may only lose a few layers of already dead cells.  Most of the time, scraping off a few layers of those “bags of keratin” isn't even noticeable.  Stratum corneum literally translates to the “horned layer.” 

So what are some of the ways that skin provides a barrier to the outside – it's fairly obvious with all those layers that there is a physical barrier formed, and the close connections between cells don't allow a lot of things passing through them.  But there are other ways that the skin provides a barrier.  The skin produces something called the “acid mantle”, which is an acidic mixture that has bactericidal and germicidal properties, protecting us from stuff that gets on the skin.  I mentioned melanocytes before – melanocytes produce melanin, which helps protect us from the sun (this is why you get tan when you're in the sun – you cause the melanocytes to jump into high gear).  Even your DNA within the skin cells enters the picture when it comes to protection – when UV rays get to the DNA, it vibrates, creating heat, and transforming the potentially damaging energy of the UV rays into relatively harmless heat energy that can be dissipated easily. 

The skin is not impenetrable, however.  Some things can get through the skin – both in and out.  Water can go both ways through the skin – we can lose moisture (primarily through sweat, as the keratin creates a mostly waterproof barrier) out, but we can also absorb water – when you sit in a bathtub, and look at your wrinkled fingers and toes, that wrinkling is a result of water being absorbed into the skin.  It also has the added bonus of improving your grip when your hands are wet, how cool is that??

Lipid soluble substances can be absorbed through the skin – this is because they can travel relatively easily through the cell membranes of skin cells, and travel in that route.  This is why some drugs can be administered transcutaneously – across the skin.   (Think anything worn in a patch form is being administered by this route.)

Some plant secretions may be taken in through the skin.  You may have noticed that some folks are susceptible to poison ivy.  The resin secreted by the plant doesn't cause a problem unless it crosses through the skin barrier, and creates the inflammatory response that we know as a poison ivy rash.  If the resin is unable to cross that barrier, there is no response. 

The type of tissue that forms the epidermis is stratified (many layers) squamous (flat cells) epithelial tissue.  Remember that epithelial tissue always has a free surface, which lines the center of a hollow organ or the outside of the body.  Other places where stratified squamous ET is found are in the inside of the mouth, the esophagus, the anus, and the vaginal canal.  The layers that are found in skin are different in these areas (why?), but can you think of some reasons why might this be a good choice for a “fence” or a barrier in these areas? 

Underneath the epidermis, the dermis is found.  Within the dermis are blood vessels and nerves and sweat glands and connective tissue that holds the party together.  Except for the merkel disks, all sensations received through the skin are transmitted to the CNS through receptors found in this layer.  We'll go more into detail with this when we talk about responsiveness and irritability.   

The blood vessels that are here give our skin two more functions – heat, or temperature regulation, and creating a blood reservoir.  Heat regulation is fairly straight forward, but let me explain the blood reservoir part.  At any given time, about 5% of your blood volume is found in the dermis.  Most of the time, this is more than what is needed for actual dermal function.  This allows for blood availability during certain activities - blood can be shunted to the muscles when you exercise, for example, or to the digestive tract after you eat.  And doing either of those activities doesn't rob anywhere else of enough blood to survive.  




 










Monday, January 9, 2017

More Foundational Concepts - brainstorming list

I need to spend time covering these as well:
Gradients
    Pressure
    Concentration
Movement across a membrane
Cell to cell communication
Cell division
    Mitosis
    Meiosis
DNA replication
Transcription & Translation
Cellular Respiration
    Aerobic
    Anaerobic
Histology


Homeostasis

Homeostasis
The last thing that we'll cover today is Homeostasis.  I listed homeostasis as one of the functions of the body that we'll discuss, but truthfully, it will be covered with every module.  For this module, I'd like to talk about what it is and how it works, and give you a brief overview about what I mean when I talk about vitalistic A&P as a way of viewing how your body works.

What is homeostasis?  Homeo – means the same, and stasis – means unchanging.  So while the term could literally mean “the unchanging same” (boring!), the truth is far from that.  Homeostasis describes the stable internal environment of the body.  Every variable in the body can be seen to be maintained in a relatively narrow “margin” of what is considered normal.  Blood pressure, temperature, oxygen levels, carbon dioxide levels, heart rate... each has their own homeostatic normal range, and that range is further influenced by the internal and external environment in which your body operates. 

(As an interesting side note here, the term Homeostasis was coined by Walter Cannon, in a book published in 1932 entitled “The Wisdom of the Body” - sounds quite a bit like what we're talking about with vitalism, no?)

Another way of thinking of homeostasis is a dynamic state of balance or equilibrium.  If a variable moves to the edge of the margin of what is acceptable, or outside of it, the body responds in a way to bring it back into balance. 

Homeostasis, as you can probably guess, or you may already know, is incredibly important.  It is our body's prime directive – that order that overrides everything else.  Maintaining a stable internal environment is what every part of your body functions to do.  We live in an unstable world, and everything that we interact with affects our bodies.  Homeostasis is vital to life – loss of homeostasis results in disease, and ultimately death. 

            Feedback loops
Have you ever taken care of a swimming pool?  One of the things that you do regularly with a pool is test the water, right?  You test pH, chlorine levels, and other things to determine if things are within acceptable and safe limits, or if there are changes that need to be made.   I grew up in CA, and we had a pool – I always loved getting the pool water into the little tube things, adding different things, and watching colors appear.

The very first thing that needs to happen when your body is trying to maintain homeostasis around any given variable is detection of that variable, right?  A RECEPTOR that detects the changes of that variable must be present.  (In the pool, the receptor was the tube thing, and adding the different chemicals from the dropper made the changes visible to my eye).

The receptor is not intelligent in and of itself, it cannot do anything with the information it detects alone.  In the pool example, this would be like I just left the tubes by the pool, even after adding the different indicators, and didn't do anything further.  However, the receptor reports to a CONTROL CENTER.  When I was testing the pool water, the control center was the booklet that came along with the test kit.  If something turned blue, it told me chlorine was needed, etc..  I could know if chlorine or whatever was needed to the pool based on what was being detected in my tubes (the receptor).  In our bodies, the control center is typically within the central nervous system, and the control center takes in the information and dictates the proper response.

The EFFECTOR is what performs the response.  So in my pool example, I was the effector – I was the one that got to add what was needed or perform the necessary changes to the water.

There are two types of feedback systems – positive and negative feedback.

We'll cover negative first, because that is easier to understand: In a negative feedback loop, the effector action turns off the trigger to the loop.  If the system was triggered because of high blood sugar levels, for example, the effector action lowers blood sugar levels to stop the loop.  (Or, if it's low blood sugar levels that were the trigger, the effector action would raise blood sugar levels in response)

Because the effector action shuts off the loop, it's called negative feedback.

Positive feedback is the opposite.  The effector action increases the trigger, increasing the response.  Typically, positive feedback systems create a cascading effect that continues until something outside the system stops it. This sounds illogical and is kind of counter intuitive.  Let's look at times where positive feedback is used for examples.   Contractions during childbirth are an example of a positive feedback system:  Oxytocin is released from the pituitary gland, and causes contractions.  The contractions push the baby's head against the cervix.  Pressure on the cervix in turn cause a signal to go to the hypothalamus (where the hormone is created) to produce more oxytocin, which when released into the blood, creates stronger and more contractions, increasing pressure on the cervix and so on.  The process continues until the contractions completely push the baby (or babies) out, and the uterus is emptied.  The emptying of the uterus is what shuts off the loop, because the baby is no longer stretching the cervix.  Blood clotting and lactation both also work by positive feedback systems. 

Clear as mud, right?  It doesn't really matter if you completely understand the positive vs. negative feedback thing now.  Just be aware that our bodies have these two types of feedback, one turns off the initial stimulus, and the other turns in on higher and higher until something else happens to turn it off. 

I promised that we'd end this module with an example of what I'm talking about with vitalistic A&P.  So since we've started covering homeostasis, let's look at one of the basic homeostatic mechanisms of the body – temperature control.

Humans are fairly unique in the animal world because we are able to adapt, and even thrive, in quite a range of temperatures.  There are human populations in the cold arctic regions, as well as in hot desert climates, and everything in between.  As long as the external temperature is within our acceptable range, however, our bodies adapt and change so that the internal temperature remains acceptable as well.  Our internal temperature range of acceptable is quite a bit smaller than the external temperatures, and it's a testament to how amazing our bodies are that we are able to maintain ourselves within that small acceptable internal temperature range.

(And just to clarify, at the moment, I'm not talking about temperature increases that occur when your body is fighting something – we'll go over immune functions at a later date.  This is just looking at temperature for normal every day life.)

It's important to remember that if you know what needs to be accomplished, the things that the body does make perfect sense.  If we're too cold, our bodies work to get warm.  If we're too hot, our bodies work to cool off.  If you can step back and say “what are all the ways I can do X (generate heat, lose heat, raise blood sugar, etc), you'll generally come up with a mostly complete list of what your body will do in response to the stimulus.  So when we're looking at these different responses, we'll start by generating the list of things that your body does, then address them each specifically as far as how your body does that.

If your body starts getting too cold, what does it want to do – warm up, right?  So how can we do that?                                               Answer:  reduce heat loss and generate heat. 

When you start getting too cold, the first thing that happens is that the thermoreceptors, nerve receptors that measure temperature, both in your skin and internally, send information to the hypothalamus telling your brain that it's getting cold.  In response, the hypothalamus will trigger a series of responses that shift your body to help keep you warm.  The autonomic (or involuntary) responses triggered are: 
            Shivering – for heat generation from the muscles.  Although skeletal muscles are voluntary, shivering is typically not.  Your ANS takes over and says that heat production overrides the resting state of the muscles.  Unless you are very very cold, you can still move voluntarily, but if your muscles are resting, they will be shivering with quick contractions to generate heat.  
            Goose Bumps – we're relatively hairless (or most of us are!), so this doesn't make as much sense for us as it does for other mammals, but goose bumps help to retain heat by causing the hair to lift away from the skin and trap heat in between the hair and the skin.  They are caused when the arrector pili muscles, which attach to the shaft of hair in your skin, contract, pulling the hair shaft more upright.
            Shift in blood flow – heat is primarily lost through the skin, so if your body temperature is dropping, we want to avoid heat loss at the skin.  One way of doing this is for the arteries and vessels close to the skin to vasoconstrict (close) so that less blood (which carries heat) makes it to the surface of the skin.  Shifting blood flow away from the skin brings blood (and heat) internally, hopefully heating up the internal organs, and keeping the more internal thermoreceptors happy. 
            Warmth seeking behaviors – although we have control over these in respects to if we actually perform them (or are able to perform them), they are triggered by the information coming through your ANS.  So putting on a sweater, coming inside, standing by the fire, drinking something warm – are all driven by your subconscious mind making them happen.  Putting on a sweater, or a blanket, or coming in from outside, all of these decrease the information about cold temperatures, and help to restore normal temps in your body. Drinking something warm has the added benefit of also heating up the internal thermoreceptors, as well as holding something warm in your hands. 

In the next module, we'll cover how we maintain boundaries.  We'll talk about it on a cellular level, as well as from a systemic and whole organism level.  So we'll be focusing on the integumentary system, as well as on the nervous system, we'll mention a bit of circulatory physiology, and even touch on the respiratory, digestive, reproductive and endocrine systems. 




Introduction & Foundational Concepts


First question that we must answer – What is vitalism?

Vitalism, simply put, is the idea that the whole is greater than the sum of its parts.  That there is an indefinable something that keeps the whole running – when that something is gone, the whole is no longer whole.  It is intangible, and immaterial.  But VITAL to the function of all living things.

When you die, what happens?  Your body shuts down, the parts no longer function as they once did.  But all the materials are still present – your lungs still exist, your digestive system is likely intact, ditto for the heart, the brain – organs present but no longer functioning – there is a vital spark that is missing. 

Dr. Frankenstein created his monster from parts of bodies he collected from the graveyard.  Even with carefully sewing the right parts together, the body needed a vital spark – LIFE – to function.  In Mary Shelley's book, he got it with lightening, adding a literal spark to the conglomerate body he had made.  The truth of the matter, however, is that electricity and lightening isn't the vital spark that makes us run.  Electricity is an essential part of our bodies, true – our muscles use electricity to contract, and ditto for information going through the nervous system.  But electricity is only the message, it is not what creates the message.

In Chiropractic, we call that vital force Innate Intelligence, and we say that it's in every living thing, in fact, the Chiropractic “Meaning of Life” is described as the expression of innate intelligence through matter.  It is not a strictly chiropractic concept (although the term Innate Intelligence is) – in Indian Philosophy, the Sanskrit word is prana - described as a vital life force.   In Eastern Philosophy, it's called qi.  In the Pacific Islands, this life force is called mana.  In the Star Wars universe, it's just called “The Force”. 

Now, if you look up vitalism on Wikipedia, you'll see a page that makes it sound like it was debunked hundreds of years ago, and no one sane believes it any more.  In fact, it might be this discord which drew you to the course in the first place.  The truth is, vitalism is alive and well – I know many many sane professional people (scientific folks, even), who embrace it and operate from the paradigm on a day to day basis.  Not just chiropractors, either.  :)

Before I get to combining vitalism and A&P, let's contrast vitalism with its opposite philosophy – mechanism.  Where vitalism says the whole is greater than the sum of its parts, mechanism says that the whole can be understood solely by understanding the parts. 

Where vitalism talks about the parts being integral to the whole, mechanism dismisses parts without hesitation.  That spleen?  You can do without it – take it out.  Appendix?  Accessory organ, unnecessary... you get the idea.  Vitalism assumes a higher intelligence at work, mechanism claims understanding.

Vitalism acknowledges an inborn intelligence ordering matter, mechanism says that no such intelligence exists, and thinks that our conscious minds can explain, comprehend, and create everything that we need to.

Western medicine is steeped in the hubris of mechanism.  Most alternative healing professions come from a more vitalistic perspective.

So Why pair vitalism and A&P? 
Virtually every A&P textbook I've ever seen is written from a mechanistic perspective.  The body is divided up into systems, and each system is studied individually.  To be fair, while discussing the cardiovascular system, the nervous system influence on the heart is mentioned, and ditto for the respiratory system and so on.  Unless we look at A&P from the perspective of vitalism, however, the millions of connections and interrelatedness of every tissue cell and organ in the body is missed, or at best, glossed over and one must study very hard pulling information from many sources and chapters to get a glimpse of the whole picture.

This course is designed for someone who has had some exposure to A&P.  I'm assuming that you have all had at least an introductory level anatomy and physiology class.  So while there are some basics that I will cover and review, they will be presented with an understanding that it is a review, not a new concept.  If you need further information about any of these subjects, refer to the references given at the end, and by all means ask questions.

I mentioned that this series was going to be divided into different functions rather than systems.  In order to do that, however, there is some basic underlying concepts that I need to cover first.  So the first module will review some terminology and some basic chemistry, biology, and physiology that we will continually reference as we go deeper in our studies.

This means that at least the first part of this module will feel a little more like the traditional things that have always been covered in A&P – bear with me – I promise it won't feel like a traditional class soon enough!

Terminology
What is commonly called “Medical Terminology” is actually one of my favorite subjects.  It's fun because once you know meanings of things, you can create all sorts of fun words, and once you understand the pieces, you can pull apart those extraordinarily long words found in journals and textbooks and make sense of them.   Now, I'm not going to go into everything here – a quick online search will lead you to several free online medical terminology classes.  Even though they are divided up by systems (it makes more sense when studying the terminology than it does the function!), I recommend finding one that you can book mark and reference it when necessary.  I'm just going to give you a really brief overview of some of the important parts.

There are three basic puzzle pieces that are used – prefixes, root words (or RW's, which become combining forms (CF's)) and suffixes.  Prefixes are found at the beginning of the word, suffixes are at the end of the word, and in general, combining forms are in the middle.  Sometimes, you can make a word with just a prefix and a suffix together, but that's not typical.  A suffix and CF make a word, a prefix and CF make a word, a RW alone is a word, and sometimes prefixes and suffixes alone have their own meanings as well.  As we go through the modules, when I use terminology, I will often point out the different parts of the word, and tell you where they come from – this will help make the language that I'm using clear, but also help you remember the words and parts of words in the future, so when you see them in other forms, they'll have meaning for you.

The other thing that I love about terminology is that it's incredibly specific and precise.  Especially the directional terminology, So we're going to go over this first, because these are words that you will hear again and again, and not always words that can be picked apart to figure out the meaning. 

When you look at a map for the first time, what do you do before you do anything else most likely?  You either determine where north is, or where you are, right?  You find something on the map that you can use to orient yourself to what it is showing you.  If someone tells you to get to their house, you need to drive south and then their house will be on the left, you have to know what direction south is, correct?  (It helps to know what left is, as well!)

When referring to anatomy, there are certain standards that are used for directional terminology. 

The first is known as “Anatomical Position” - this is the starting point for ALL directional terms used when referring to the body.  If you stand up straight, have your feet hip width apart, your toes pointed forward, your arms relaxed down by your sides, your palms facing forward, and look straight ahead, you are in anatomical position.  In fact, do it right now.  Stand up next to your chair or wherever you're sitting, and assume the position!

Take a minute to notice how things are positioned – where are your pinkies in relation to your thumbs?  Where are your shoulders in relation to your hips?  We'll learn some specific terms for these relationships, but if you can remember this position, it will help you tremendously.  IT DOES NOT MATTER WHAT POSITION SOMEONE IS IN WHEN YOU ARE LOOKING AT THEM – IT IS THE POSITION OF LIMBS AND ORGANS IN ANATOMICAL POSITION ON THE PERSON THAT IS REFERENCED THAT IS USED TO DESCRIBE THE RELATIONSHIP.

Because of that standard, when one health care professional is talking to another, there is a common definition of superior, inferior, lateral, medial, etc.  The precise terminology allows for a common language, which (ideally) decreases errors and makes for consistency.  It doesn't matter if the patient in front of them is lying on their side or on their back, or if the practitioner is on their right side or left side.  Anatomical terminology will allow them to directly reference the same point on that person. 

The directional terminology that we'll cover today is:

Superior - above
Inferior - below
Cephelad (Cephalic) - towards the head
Caudad (Caudal) - towards the tail
Proximal - closer to  
Distal - further away from
Medial - towards the midline
Lateral - further away from the midline
Superficial - towards the surface of the body
Deep/Internal - below the surface
Prone- lying face down
Supine - lying face up
Pronation - commonly used for the hands, palms down
Supination - again, commonly used for the hands - palms up (think holding a bowl of soup (sup)
Inversion - commonly used describing the feet - turning the sole of the foot inwards (sometimes refered to as supination, even with the feet)
Eversion - again, for the feet, turning the sole of the foot outwards (over-pronation)
Abduction - moving a limb away from the midline
Adduction - moving a limb towards the midline
Flexion - making a joint angle
Extension - making a joint angle larger
Dorsal - the back of the body
Ventral - the front/belly of the body
Anterior - the forward part of the body
Posterior - the back part of the body
Transverse plane - divides the body into inferior and superior segements
Frontal/Coronal plane - divides the body into anterior and posterior segments
Oblique plane - divides the body at an angle
Sagital plane - divides the body into right and left segments
Midsagital/Median plane - divides the body evenly into right and left halves

It's important to note that some of these terms are synonymous on humans because of anatomical position - ventral and anterior, dorsal and posterior, superior and cephelad, inferior and caudad for example.  In dogs, ventral and inferior are synonymous, and anterior and cephelad are as well.  

As we go through the different modules, we'll be adding to the terminology list, but these are terms that regardless of subject matter, you'll hear and you should be familiar with.



Some basics of Chemistry and Biology:  Atoms, Elements and Ions – oh my!

Remember the periodic table of the elements?  Yeah, me too.  Don't worry, you don't have to quote it or memorize it, or even know which column is noble gasses (although strangely, I do remember that even though I've never used it outside of the chemistry lab!).

What you want to understand about chemistry is this:

Atoms are the building blocks of everything that you see, they are composed of protons, neutrons, and electrons.  Protons have a positive charge, neutrons are neutral, and electrons are negatively charged particles.  As we progress, typically the thing that we'll be most concerned about are electrons when we talk about chemical interactions.  The center of the atom is called the nucleus, and it is where the protons and the neutrons are stored.  The electrons circle the nucleus, much like planets orbit around the sun.  An atom is neutrally charged, because it has the same number of protons and electrons.   You don't need to know about how the atom appears in an atomic drawing, or what the electron clouds look like – if you want to pick up a basic chemistry book and review this, you're welcome to, but it won't be covered here.

(That periodic table that you remember?  It lists all the different types of atoms known to us at this time.  They are organized according to different properties that the the elements have in common given a similar structure.  And while atom = element is not entirely true, for our purposes, at this time, you can think of them that way.  An element is the smallest thing that you can have and still have gold, for example.)

Atoms join together to form molecules.  And molecules can join together to form compound molecules.  Some molecules, in turn, break into ions when they are dissolved.    Ions are charged particles of an element.  When a molecule breaks apart, sometimes the ion will have a few more electrons than it did before – if that's the case, the ion is negatively charged and called and anion.  If it has less electrons than protons, it is positively charged and is called a cation.   Cl- is a chloride ion – it has one more electron than proton, so it is negatively charged.  Mg2+ is a magnesium ion – it has two less electrons than protons, so it has a 2+ charge.

You should know about a few different types of molecules.   Most of them should be familiar to you, so we'll quickly go over the definitions so we can get on to the more fun stuff:

Water (hydrophilic/hydrophobic)
Protein
Fat/Lipid
Carbohydrates
Alcohol
Nucleic Acids
ATP (and other high energy compounds)
Salts

Just a few other important concepts and we can leave chemistry behind.

Solution vs. Colloid vs. Suspension
Concentration, Osmosis, Diffusion
Acids/Bases/Buffers
pH

That's it – we just covered the extent of the basic chemistry knowledge.  So if the thought of revisiting chemistry had you sweating and hyperventilating, relax, sit back down, and let's move on to some biology basics. 

Biology and Anatomy & Physiology
(Note: A lot of what is covered in a basic biology course will not be covered here, because it is not relevant to what we are talking about.)

When you get enough of the right molecules together, in the right manner, you can form some really important biological building blocks.  DNA, cell organelles, cells... and eventually tissues and organs and organisms!

The Cell
Cells are typically thought of as the building blocks of life.  The simplest creatures are one celled organisms (aka unicellular) like protozoa and bacteria.  Our bodies are made up of trillions of these tiny building blocks.  Inside cells, are smaller structures called organelles, which help the cell perform the functions that it is required to perform.  Anytime you see the suffix -elle, think “little” of whatever the rest of the word is – so organ-elles = little organs.  As necessary, we will cover the specific organelles in more detail, but for now, here's a brief reminder of the organelles that are most common:

Cell membrane/Plasma membrane – in some cases, it has a different name, but it is the cell membrane which separates the inside of the cell from the outside of the cell.

Cytosol/Intracellular fluid/Cytoplasm – all these words refer to the fluid inside of the cell, the rest of the organelles are floating freely or are anchored in some way inside this fluid.

Nucleus – The nucleus is where the DNA is found – the blueprint for life.  A cell may have one of these (uninucleate), or many (multinucleate).  Although there are cells without nuclei (called prokaryotic cells), they are not part of the human body per se (we'll talk more about the human biome at various points, especially when discussing digestion, and we'll cover a little bit about them at that time).  The nucleus (and its contents) are separated from the rest of the cell by the Nuclear Envelope.  The fluid inside the nucleus is sometimes called the nucleoplasm. 

Nucleolus -  a structure that is found within the nucleus composed of proteins and nucleic acids.  We'll talk more about the inner workings of the nucleus at another point.

Endoplasmic Reticulum – There are two types of ER – smooth ER, which lacks ribosomes, and rough ER, which has them.  You can think of the ER as the manufacturing plant of the cells – it is here were protein synthesis, lipid synthesis, and the production of other important things usually takes place.

Lysosomes – these are free floating bags of enzymes that break down waste products or things not needed in the cell.

Mitochondria – the energy powerhouses of the cell – the Krebs cycle occurs inside these tiny structures, and is the primary source of energy within the cell.

Centromeres – organelles that are active during cell division.

Golgi Apparatus – creates some molecules, but functions more for packaging secretions to be released outside of the cell.

There are a few other organelles, and in many cases these organelles are modified in certain cells (and sometimes renamed – oy!) to perform whatever function that cell must perform.

We'll cover the modifications and more specifically the function of the individual organelles as we talk about different body functions. 

Tissues and Organs
A tissue is defined as two or more types of cells collaborating to perform a specific function.  There are four general tissue classifications:  Epithelial, Connective, Muscle, and Nerve. 

Each tissue is specially designed to perform a specific function.  Epithelial tissues are found covering and lining, Connective tissues support other tissues, Muscle tissue allows for movement, and Nerve tissue allows for long distance communication.  We'll discuss individual tissues as we need to cover them.  Remember that even on a microscopic level, there is a relationship between what something looks like and the job that it does. 

Organs are defined as two or more tissue types working together to perform a specific function (or functions). 

Systems are defined as two or more organs working together to perform a specific function or functions.

You may hear of “levels of organization” - from small to large, as relevant to A&P, they are:
Chemical level (atoms and molecules)
Cellular level (organelles and cells)
Tissue level (tissues)
Organ level
Organ System level
Organism level

For much of what we'll cover, we'll do some bouncing from level to level, so it's helpful to remember where you're at as far as levels of organization.  I'll be as clear as I can, especially when I jump from level to level!

Anatomy is the study of where things are in the body.  Anatomy answers the question “What is that?”

Physiology is the study of function – it answers the question “How does this work?”

They are often viewed together initially (like in the intro A&P class), and then when covered in more depth, separated.  However, they are connected, and you can't really study one without the other.  The term complementarity is often used to describe this relationship. 

As we go through different concepts, one that links everything together is simple to remember:

ALWAYS ASK “WHY?”

Why is something located where it is?  Why is it connected to that?  Why is it shaped like that?  Why does it produce that?  If you can start asking, and answering, these questions, you'll find that a lot of A&P is quite intuitive – the stomach is shaped like a bag with ties on either end so that it can mix up the stuff that comes into it with the juices it produces.  Even on a microscopic level, the question of “What does that do?” can often be answered by understanding what it looks like.  The walls of the alveoli, in the lungs are made up of a single layer of flat cells, ideal for gas exchange to occur across them. 

Wolff's law:  Form follows function, and function follows form.  A great rule to remember as you learn. 

If you can start asking and answering the why question, you'll have an easier time putting the pieces together!

A few last concepts, and then we're done with the review of the basics, and we can move onto other things.

In order to maintain life, there are things that an organism (and we'll be talking specifically about humans) must do.  There are also things that are required in our environment.

The things that we must do can be termed necessary life functions.  We've already covered some of the things on this list – and mentioned that they will serve as the focus for future chapters.  Some of them, such as responsiveness and metabolism, are too extensive to be covered in any one module, and will be covered as they apply to the more specific functions. 
            Maintain boundaries - separate self from not self
            Movement - get from point a to point b, and have things move around internally
            Responsiveness or Irritability - detect external environment and changes, and respond appropriately to them
            Digestion - bring in nutrients from outside the body, process them to a usable state, and get them where they are needed
            Metabolism - all of the chemical reactions that take place in the body
            Excretion - getting rid of waste products
            Reproduction - making new life

The environmental requirements are things that must exist in our environment to allow life to be sustained.  They include:
            Nutrients - we cannot make our own food - we need food from outside the body
            Oxygen
            Water
            Appropriate Temperature
            Appropriate Atmospheric Pressure


Purpose & Outline

What is "Vital A&P"?  It is looking at A&P from vitalistic, rather than a mechanistic perspective.  Everything that happens in our bodies is a result of something else – but there is an intelligence to how our bodies operate, and without that intelligence, they don't work.  When that intelligence is stopped, death occurs.  There are metabolic processes, cellular processes, communication between cells, messenger systems, long distance communication, even inter species collaboration all occurring in our bodies.  It's fine to break everything down into little pieces to learn it, but when you look at the overall function, until you grasp that the whole is greater than the sum of its parts, you lose an integral part of the picture.

In this book, I aim to review basic A&P concepts, and reveal just how intricately the systems are related to each other.  Rather than using a system by system approach, we will be talking about different functions that our bodies perform, and in the process you will see the millions of connections between the systems, and hopefully realize that studying the body in a systemic approach loses much of the the wonder of the body.

We often think that if we are talking about respiration, the only system we are looking at is the respiratory system.  However, while it can easily be seen that the respiratory system might be primary in that function, it's imperative that the cardiovascular system also be functioning.  The kidneys need to function.  The nervous system needs to properly function.  Hormones need to be properly balanced, and even the digestive system plays a role.  For every function of the body, every system needs to be working.

I'm hoping that this textbook will bring some of those connections to light for you, and to spark your interest in further studies along these lines.  For too long, we have been studying A&P from a systemic perspective – let's bring the whole being back into the picture!

The text is broken up by necessary life functions.  For some chapters, we will cover functions that are commonly associated with specific systems, but bringing in the other systems necessary for the function to occur fully.  So you'll hear about both the “lead actors” - systems or organs with starring roles, and the “supporting actors” - the organs and systems which are vital to the overall function being discussed, but with more “bit parts”.  Some of the necessary life functions will be covered in every module, and you will see how every necessary life function must be working in every smaller part.

The tentative outline for chapter subjects is as follows:

Foundational Concepts - In this chapter(s), we will cover the necessary foundation concepts that will help you understand the rest of what is covered.  Most of them you have probably been exposed to before, possibly in greater depth.   Here, we will cover them to the depth that you need to understand them to in order to grasp the rest of the text.   You can bookmark this chapter or particular concepts to review as they are covered in later chapters.

Maintain boundaries & Responsiveness– how the body keeps the inside in and the outside out, and how we are able to detect changes in and respond to our environment.

Movement – how we get from A to B to C and back.  We'll discuss internal movements more in depth as they apply to other functions.

Digestion – how we bring in nutrients to the body and process them

Excretion – how we get rid of the stuff we don't want inside.

Respiration – gas exchange in and out of the body

Reproduction (Parts I and II) – how we create new humans and propagate the species.

Growth – how we get bigger – we start out as two cells joining – how do we get from there to adulthood?

Stress vs. Relaxation – we have essentially two states of being – rest/relaxation, and fight/flight – in this chapter we'll explore the differences and how each are essential, and what happens when the balance shifts.

Immunity, Healing and Repair – our bodies not only maintain boundaries, we protect them – the immune system is the guard on the wall, and the soldier that protects us every day.

Homeostasis – how our bodies maintain a consistent internal environment.  we'll cover this a little bit today, and our final chapter will be pulling everything back together covering the big picture of homeostasis again.


 


Saturday, January 7, 2017

Getting Things Underway

This will be the online location that I use to write bits and pieces of my textbook, Vital A&P, and where I will be looking for feedback from those of you lucky enough (!) to be reading it.  Some of what will be here is outlines and brainstorming sessions, other posts will be more complete coverage of concepts and chapters for the work.

I'm excited to start making this happen.  Here's to 2017 being the year of writing and getting this concept out of my brain and into the world.

:)

Mindi