Download 8.2-Whole-Human-Physiology

Whole Human Physiology: processes of digestion, assimilation and
elimination
Qi, or Vital Force, that is derived from food is distilled into energy for us by our
processes of digestion and assimilation. The waste from this distillation is removed from the
body by our eliminative channels. This complex process includes a variety of ‘body systems’
(in conventional terms):
The mouth and esophagus
The stomach
The small and large intestines
The colon
The kidneys and bladder (urinary systems)
The skin
The human cell
Keep in mind that this process and its relevant ‘systems’ cannot be take out of context: for
example, processes of perception are intimately involved in determining what nutrients and
foods we will accept and what nutrients and foods we will reject; processes of regulation
and adjustment give rhythm and timing to the whole cycle of absorption; processes of
analysis and expression will affect what foods we eat and why. But let’s take a closer look at
the Whole Human’s process of digestion and assimilation for now:
The mouth. Any intake of food begins here. The mouth is an incredibly sensitive organ in and
of itself, and it includes the teeth, tongue, salivary glands, and oral mucosa. The teeth begin
the process of break-down of foods, mechanically mashing everything up. When combined
with the enzymes contained in the saliva, food is quickly turned into a juicy, pulpy substance
that can easily be passed down the esophagus and on to the rest of the system. It is vitally
important to completely chew and saturate your food with saliva, especially in cases of
sluggish digestion, to ensure proper absorption. However, the process of absorption of Qi
has already begun even before the first swallow: the tongue interprets and absorbs subtle
(and not-so-subtle) cues from food in the form of flavor, texture, and chemical constituents.
These cues are instantly transferred into signals and energy for the rest of the physiology: for
example, the bitter taste will almost instantly begin to activate the whole rest of the
digestive system (which is why we take bitters before meals to stimulate this process if it is
sluggish). In addition, the oral mucosa, which consists of the soft tissue of the inner mouth,
gums, and under the tongue, is laden with capillaries that are very close to the surface,
creating a vehicle for absorption that is almost as direct as the lungs. This is the reason
behind sublingual (literally, ‘under-tongue’) absorption: many chemicals diffuse right into
the bloodstream through the capillaries of the oral mucosa, bypassing the rest of the
digestion and being instantly added to the Qi pool.
The esophagus. At the back of the mouth, the cavity meets up with channels from the nose
and sinuses (the joining or the oropharynx and the nasopharynx), and begins to slope rapidly
downward. Right there, however, there is an important valve, the epiglottis (‘above-thethroat’), that makes sure that food goes down the esophagus and only air gets transferred
down the larynx, to the lungs. We’ve all had times food or drink has ‘gone down the wrong
pipe’ – instant coughing results as the bronchial tubes expel the unwanted material. The
most important function of the epiglottis is to fold over the larynx and keep food from
entering the respiratory tract – it moves to cover this vital system every time we swallow.
The stomach. Situated right behind and below your sternum (the last connected ribs), the
stomach receives the pulped-up, pre-digested food mush and continues the chemical
breakdown of nutrients and distillation of Qi. There are two main digestive secretions that
come from the stomach: hydrochloric acid (‘stomach acid’), and enzymes such as pepsin.
These secretions aren’t active
all
the time, however: they
become activated in response
to
the signals sent by the mouth
(and, even before that, by the
nose! And, even before that, by
the
processes of adjustment /
regulation signaling that we’re
hungry and it’s time to eat).
Stomach acid, which comes
from so-called ‘proton pumps’
in
the lining of the stomach,
serves two main purposes: it
sterilizes food, killing most
bacteria and severely messing
up
viruses that may be present in
the
food; it also starts to chemically ‘break up’ complex carbohydrates into simpler sugars, and
‘denatures’ proteins by beginning to break them up as well. However, stomach acid alone
isn’t really enough to do the trick and make most proteins and sugars really absorbable; to
this end, the stomach also secretes digestive enzymes that continue the process of breaking
down carbs and proteins into simple sugars and amino acids, and separate fats.
The stomach also absorbs subtle energy from the food it is breaking down: right at the
sternum, where the stomach is housed, is a bundle of nerves second in size only to our brain
and spinal column, called the solar plexus. It senses very closely what the stomach is
digesting, and responds by sending reflex signals to the rest of the nervous system. It also
controls the secretions of the stomach to a certain extent – the oft-mentioned ‘butterflies’
come from a nervous solar plexus impulse. In addition, many herbs have an effect on the
whole human by stimulating energetic responses from the solar plexus, before ever being
absorbed by the digestive system. This is the mechanism of action of many expectorant and
carminative herbs, and can help refute the ‘biochemical’ complaint that “herbs don’t work
because all of their constituents are destroyed in the stomach and never make it into the
bloodstream to effect therapeutic change”. Well, the process of ‘destruction’ itself and the
nervous impulses that result from it are, in fact, mostly responsible for the therapeutic
change many herbs have to offer!
The small intestines. The stomach passes its well-digested material, or chyme, into the
duodenum and from there to the jejunum and ileum, all portions of the small intestine. This
is a series of highly folded ‘tubes’ lined with an epithelium that is itself highly folded and
covered in villi, micro-folds in the epithelium, and thus these tissues have an incredibly large
surface area within a small space. As the chyme travels through the duodenum, it is mixed
with bile from the liver, gallbladder and pancreas (more on these organs later, when we
discuss adjustment and regulation in the whole human), which gives the final break-down of
chemical constituents and emulsifies fats for easier absorption. Now, the bulk of the Qi from
food can finally be absorbed, in the form of sugars, proteins, vitamins, essential fatty acids,
minerals, and other vital nutrients that dissolve through the villi into the blood of the portal
vein. From here, these chemicals are transported directly to the liver, where they are further
broken down (if necessary) – but again, more on this later. What is important to remember
is that, though the union of chyme and bile, the process of distillation of Qi is almost
completed.
The large intestine. There is still a lot of moisture available that the small intestine doesn’t
absorb from the digested food; it is the task of the large intestine to remove this moisture
and introduce it to the body for use, along with minerals present in the water (electrolytes).
In addition, the large intestine houses many of the beneficial bacteria we use to digest the
last bit of nutrients that the rest of the system has missed. The digested food passes up the
ascending colon, across the transverse, and down the descending colon, by which time most
of the moisture has been eliminated and feces are ready for excretion through the rectum.
You can see how much movement is required to transport food and waste around the loop
of the colon: it occurs in response to the many cues signaled by the mouth, stomach, and the
processes of adjustment and regulation in the
body,
all intricately woven together into the
process
called peristalsis. Normally, a complete
peristaltic cycle occurs at least once daily.
The kidneys and bladder. These all-important
organs
serve many different functions, primarily
regulating the water balance of the whole
human, and as such will be discussed in
greater
detail when we investigate
adjustment/regulation. However, they play
an
important eliminative role by flushing out excess moisture from the system, and are thus a
part of the body’s eliminative channel, the final part of the process of digestion and
assimilation. Basically, the kidneys are complex filters formed of many tubules, or nephrons,
that screen all our blood as it flows through them (by way of the aorta and vena cava, see
diagram on right). In a two-step process, they first screen out large molecules and cells such
as red blood cells, re-introducing them into the bloodstream. In the second step, they
reabsorb a large portion of the electrolytes, sugars and proteins through active transport.
Urea and other toxins are eliminated with a small portion of water, and pass through the
ureters into the bladder for elimination as urine. The flow of this whole process is regulated
by the kidneys in concert with the hypothalamus and pituitary glands, as well as relying on
signals from the liver and pancreas as they relate to the bloodstream.
The skin. An often neglected but extremely important organ of water elimination, the skin
processes through toxins from the blood and lymphatic system on an ongoing basis. It is
often called the ‘third kidney’, and as such plays an important role in maintaining water
balance. Sweat is excreted through the sebaceous glands in the epidermis, and out through the
pores that function much as stomata do in plants, opening and closing as needed. The sweat
response is closely tied to the processes of adjustment/regulation, being affected by
environment, emotion, activity level, and water content in the body. Many metabolites are
excreted in the sweat: along with water, there are always dissolved minerals (electrolytes)
and often toxins bound in the oily fraction of the sweat. In addition, the sebaceous glands
function as a system of ‘communication’ with the outside world, by distributing the unique
scent of the Whole Human. It is important that perspiration happen freely, especially upon
exertion, for all the reasons stated above.
The human cell. We have already looked at a plant’s cell. The cell of a human (and of most
animals) isn’t too different: it is missing a
rigid cell wall (fortunately, so we can
move – instead, our cells have a more
flexible cytoskeleton to help retain their
shape), and has no chloroplasts
(otherwise, we would be green and could
absorb energy directly from the sun). For
the process of absorption to be complete,
nutrients must be absorbed into the cytoplasm, or cellular fluid, from the space outside the
cell. There are a variety of mechanisms to transport these nutrients across the cell membrane,
which is made of fats and proteins: fats usually just go right through. Minerals and sugars are
ferried back and forth, according to cellular needs, though active transport that involves the
expenditure of energy. Most proteins don’t actually go through: they ‘bind’ to structures on
the cell membrane (receptors), and initiate changes inside the cell by changing the receptor’s
structure.
Imbalances in processes of digestion, absorption, and elimination
Most of the imbalances in the Whole Human can be resolved by addressing the flow
of Vital Force (Qi) through the processes of Adjustment/Regulation/Repair ~ after all, it is
these processes that initiate ‘symptoms’ to attempt to revitalize various other systems. In the
case of Digestion/Absorption, for example, many imbalances can be corrected by working
on the regulatory power of the Liver, and we will discuss this later. However, there are
specific imbalances in the flow of Qi through this system that can be directly addressed.
Excess: Excess in digestion and absorption is usually manifested in the stomach, where there
can be an overabundance of production of hydrochloric acid and other secretions. This can
lead to a generalized pattern of chronic ‘fire’, or excess, of Qi as the Whole Human’s
‘distillation furnace’ burns a bit out of control. Some of the root causes of this excess are:
constant eating (snacking throughout the day keeps the furnace constantly fired, setting up a
flow pattern that is excessive); use of suppressive medications (mostly antacids, which, once
started in response to a condition of acute excess like overeating at a feast, can set up a
constant pattern of excessive acid production as the Qi attempts to compensate for the
suppression); and an ongoing nervous system ‘fire’ transmitted to the stomach by the solar
plexus. In Western terms, some of the ‘diseases’ that result are called ‘heartburn’ or ‘peptic
ulcers’.
Acute symptoms of excess include temporary conditions similar to the chronic ones
described above, mostly as a result of overeating. This is your classic ‘heartburn’. Another
specific case of acute excess in the digestive system is the ‘stomach flu’, or ‘food poisoning’,
in which the Whole Human’s distillation furnace was unable to destroy toxins present in the
food during the process of refining it into Qi. In this second case, it is important to notice
whether the imbalance arises from a generalized deficiency in digestion (see below), or just
unusually poisonous food. You can determine this by asking which patter (excess or
deficiency) is usually present in the system, by going through the symptoms of each
imbalance.
Deficiency: Often, a deficiency will ultimately be behind symptoms of excess, as the process
of Adjustment attempts to compensate for the lack of Qi in this area. However, deficiency
often manifests on its own in the digestion, through bad eating habits, improper nutrition,
damage to the regulatory processes through stress, suppression through drugs, and
incomplete chewing (after all, if we start with a deficiency in the mouth, it will follow
through the whole system. The upside is that we can control how we chew!). The imbalance
of deficiency will primarily result in ‘airy’, or gassy, symptoms throughout the digestive
tract, which tends to result from incomplete distillation of food. Another clear sign of
digestive deficiency are bits of undigested food in the feces. Ideally, the only products of this
distillation should be Qi, urine, and feces: ‘wind’ is an undesired by-product. More often
than not it is difficult to directly address the symptoms of deficiency by working on the
digestion only: while warming carminatives may be of help, the underlying reason needs to
be addressed by effecting change in the adjustment/regulatory system. However, it is
important to do so promptly if deficiencies in digestion are found, because without proper
absorption the Whole Human’s reserves of Vital Force will dwindle. This important
imbalance is usually just termed ‘gas’ in Western symptomatology.
Another symptom of deficiency in digestion, which is a bit cooler and more ‘watery’, is
‘diarrhea’. This is an imbalance of the large intestine, and can have a variety of causes. It is
usually (hopefully!) more acute in presentation, and therefore probably linked to some form
of excess (perhaps infection?) elsewhere, but needs to be treated with tonifying, Qi-building
herbs quickly and effectively, otherwise the Whole Human will quickly lose Qi (in the form
of essential electrolytes and water) and could become quite compromised.
Congestion: Congestion occurs primarily in the eliminative channels, and can cause backup of
waste materials into the rest of the digestive process. This will result in sluggishness, usually
an ‘earthy’ imbalance, and can eventually damage the whole system and the processes linked
to it. Qi and vitality will become affected more or less quickly, depending on the eliminative
channel involved. There is usually some feedback loop with the process of
regulation/adjustment as well, perhaps leading to chronic congestion-to-excess patterns.
‘Constipation’ is perhaps the most common complaint here. In addition, there can be
congestion in the channels of water elimination: these tend to be a bit more serious in the
long-term, although not as debilitating in the short term (so, they often get ignored for a
long time): kidney congestion will cause symptoms such as ‘edema’, or fluid retention, and
eventually will raise blood pressure. Congestion in these organs is usually a result of
improper diet (high sodium), damage from physical injury or disease, or lack of adequate
water intake (paradoxically true!). In addition, one must always look for congestion in the
eliminative channel of the skin: though easy to overlook, proper elimination through the
sebaceous glands and pores takes a substantial load off the whole human’s process of
elimination.
Most of these imbalances can be addressed through diet, exercise, and direct adjustment of
the relevant processes of regulation. Congestion in the eliminative channels should always be
on the forefront of the clinician’s mind.
We have looked at digestion, absorption and elimination first because it is the primary
external source of Vital Force in the Whole Human. Respiration is equally important, but it
more drives the movement of Qi than providing the raw materials. As such, digestion is our
direct interface with the environment (picture, for example, small children ‘tasting’
everything to get to know it) and can easily be compromised. Elimination, the crucial endphase of this process, needs to function smoothly to ensure balance in the Whole Human. A
thorough evaluation of the processes of digestion/absorption/elimination will be the first
part of the clinical exam.