For those that don’t know, I am currently enrolled at the Vermont Center for Integrative Herbalism in Montpelier, Vermont. This is the first essay in a series of articles that I will publish on the subject of Holistic Human Physiology. Please feel free to comment below.
- Define Human Physiology
Human physiology is the study of the normal functioning of the human organism and its processes.
- Differentiate between allostasis and homeostasis
It is essential for herbalists to understand and be able to communicate the concepts of allostasis and homeostasis. Homeostasis is the more commonly used term that encompasses the self regulating actions of an organism. We can see this in basic bodily functions such as the regulation of mineral salts in the body. If we spend all day outside in the hot sun, our bodies will sweat in order to cool us down and regulate our temperature. Once we start sweating, we lose water and electrolytes. Our bodies recognize the need for these critical substances, so we become thirsty and seek out water and salts.
Allostasis is a more recent term which takes into account all manner of input on the organism. Genetics, nutrition, parents, environment, education, all of these things and more make up the foundation that we are built on. The stronger the foundation, the higher levels of stress we can endure. For organisms with poorer foundations, the allostatic load that can be endured is less, and they are more likely to be prone to disease.
All systems have an input and output, this is the nature of reality. Living organisms must obtain a variety of factors in order to survive, thrive, and reproduce. If the organism is unable to obtain everything it needs, or if it is obtaining poor quality versions of what it needs, the system breaks down faster than it would otherwise, and numerous other problems arise as the organism tries to compensate for lack of proper input.
There are a variety of ways in which the human organism can push themselves beyond their allostatic load. We all start with the genetic framework that is bestowed upon us by our parents. This may be a blessing or a curse, but hopefully we will enter the world with a set of parents that are able to provide us the safety, love, nutrition, interaction, and wisdom that is needed to thrive in this world.
Let us take the example of two different children. Let’s assume that these children have roughly the same genetic predisposition. Now let’s put these children into two entirely different environments. In the first environment, the child is raised as healthily as possible, they are not vaccinated, they do not experience trauma from circumcision or parental abandonment, they are breastfed from a healthy mother, they get plenty of proper nutrition, they live and sleep in a non-toxic environment, they are exposed to plenty of fresh air, sunshine, and playtime. In the second environment, the child is heavily vaccinated, not breastfed but instead they are fed formula made from GMO corn and soy and synthetic vitamins, they sleep in a toxic environment, perhaps the parents are smokers or use drugs or alcohol, the list goes on and on. All of these factors will establish the foundation for the allostatic load that the child is able to bear throughout life. This does not even address the complexity of genetic variances which is also essential to consider.
This breast milk article describes the importance of breastfeeding. It cannot be understated how important it is for mothers to breastfeed their babies.
If the child grows up in a poor environment, then the overall allostatic load they will be able to bear will be significantly lower than their counterpart with the solid foundation. The child who grows up in the healthy environment, when exposed to stress will have an easier time dealing with the stress, whereas the child with the poor environment will have a more difficult time dealing with stress and will be much more likely to exceed their allostatic load. When the children do exceed their allostatic load, the child with the strong foundation will recuperate faster than the child with the poor foundation. These things that seem common sense have been forgotten or misunderstood by the majority of the western world.
It would be intriguing to build a long term study that compares the allostatic load of different people and comparatively analyze how they were raised, what kind of diets they were fed as children, what sort of environment they were brought up in, etc.
- Identify the components of a cell and compare their basic functions
The mechanics of the cell are fascinating and even more so when we look at the organism from a holistic point of view. Let’s examine each component piece by piece.
Plasma membrane – The plasma membrane is a semi-permeable protective barrier that allows certain things to enter and leave the cell. The primary building blocks of this plasma membrane are phospholipids. Phospholipids are composed of three components: 1) a phosophate head 2) a Glycerol backbone, and 3) two fatty acid tails. These two fatty acid tails are held to the phophate head by the glycerol backbone, making them look like a tadpole sort of creature. The phosphate headgroup is hydrophilic, or water loving. Because the fatty acid tails are long carbon chains, they are what is called hydrophobic, or water repelling. The phosphate heads stay in contact with water, while the fatty acid tails are directed away from water, thus creating the inner space of the membrane. This dynamic is what allows these molecules to form bilayers.
Within the cell is an array of components that all have important roles. Let’s first look at the Nucleus, the control center of the cell. The nucleus contains the DNA of the cell, which is the information required for the cell to copy itself. DNA is essentially the blueprints that are used to make proteins over and over again. Damaged to the organism over time will result in degradation of the DNA, which continues to be copied until the organism can no longer sustain itself.
The Nucleus also contains the Nucleolus, which is responsible for making ribosomes. Ribosomes are organelles that are made up of a large and small subunit. Together the subunits form a mechanism that essentially examines a string of messenger RNA and creates proteins for use throughout the body. The nucleus itself is commonly called the “control center” of the cell, pirmarily because it contains the DNA which is the blueprint for every protein that the organism needs to continually rebuild itself.
Outside of the nucleus is the Cytoplasm, which is composed of Cytosol, various organelles, and protein fibers that make up the physical structure of the cell. The Cytosol is the fluid is which all of these other structures float around in. Within this fluid is a concentration of sodium and potassium ions that are involved in a variety of communication processes throughout the cell.
Each cell maintains is able to maintain its physical structure thanks to a Cytoskeleton. The cytoskeleton is a network of protein fibers that literally act as a skeleton and give shape to the cell. It is made up of four components: 1) the Microvilli which increase the cell surface area, 2) the Microfilaments which form a network inside the cell membrane, 3) the Microtubules which are the largest of the fibers making up the cytoskeleton, and 4) the Intermediate filaments that include myosin and keratin. All of these structures can essentially be seen as a kind of scaffolding or interior frame that provides some structure for the cell as well as assisting in the communication and transportation within the cell.
Mitochondria are the energy producers for the entire cell. They exist somewhat autonomously within the cell, but they have a synergistic relationship with the cell, so they are not perceived as a threat. The cell provides a safe haven for the mitochondria to live, and the mitochondria creates the necessary ATP that the body needs to live. We are just beginning to study how certain herbs can benefit the Mitochondria and our production of ATP. The link below describes the use of Cordyceps and Ginseng as potential ATP boosters.
Endoplasmic reticulum are the network of membranes where the majority of protein synthesis occurs. “Rough” endoplasmic reticulum is covered in ribsomes, while the “Smooth” endoplasmic reticulum is not. Rough endoplasmic retiuculum is primarily where protein synthesis occurs via the ribosomes. Smooth endoplasmic reticulum manufactures fats. In some cells the smooth ER stores calcium ions. It is also helpful in the detoxification of harmful substances to the cell.
The job of the Golgi apparatus is to take proteins from the Endoplasmic reticulum and deliver them correctly to their destination in the body. Transport vesicles are secreted by the ER in order to move proteins into the Golgi. From here, the proteins are “sorted and shipped” navigating through cisternae and toward the cell membrane. Special secretory vesicles are created which allow the proteins to pass through the cell membrane and get to where they are needed elsewhere in the body.
One of the vesicles created by the Golgi are Lysosomes. These are small, spherical storage vesicles that act as the digestive system of the cell by creating powerful digestive enzymes that are used to break down bacteria or old components of the cell that are no longer functional. One of the fascinating things about lysosomes is the fact that they only release their digestive enzymes when they detect a very acidic environment. This seemingly innate intelligence is another example of the cells ability to self regulate. Interestingly, lysosomes will sometimes release their digestive enzymes outside of the cell to dissolve extracellular material, such as the hard calcium carbonate in bones (Silverthorn, 71). This is the reason why people are who excessive coffee drinkers (or those who eat an abundance of acid forming foods) may sometimes experience bone density loss as well as inflammatory conditions like rheumatoid arthritis. In the situation of the coffee drinker, we are creating more of an acid environment, which our lysosomes detect and are using their digestive enzymes to free some of the calcium from our bones in order to reestablish alkalinity. This is not without negative consequences.
Arizona State University has a helpful diagram of cell components which I printed and brought to my teammates. https://askabiologist.asu.edu/content/cell-parts
- Describe the structure and function of the cell membrane, and the modes of transportation into and out of cells
The cell has two mechanisms of transport allowing movement in or out of the cell. These are Active transport and Passive transport.
Passive transport requires no energy, allowing essential substances like oxygen and water to flow in and out of the cell. This occurs through the process of diffusion. Diffusion is essential the equal dispersing of molecules in a given substrate. When there are an abundance of oxygen molecules in a given area, they will naturally diffuse throughout the area until there is a relative amount of oxygen throughout the given area. We can see this on the macro level with essential oils in a large room. If you open a bottle of essential oil, at first the oil molecules will be concentrated in a given area, but over a long enough period of time you will be able to smell them on the other side of the room because these molecules have dispersed themselves throughout the room.
Water on the other hand moves passively though the process of Osmosis. Water is constantly seeking to be in an Isotonic state, where there is a relatively equal dispersing of water molecules in a given area. The kidneys are constantly regulating the concentration of blood plasma. Since the phospholipid bilayer does not allow water to pass through it, the cell has cleverly evolved Channel Proteins that allow for the easy passage of water molecules in and out of the cell. Water specific channels are known as aquaporins.
Active transport, on the other hand, requires energy in order to move material in or out of the cell.
The cell membrane prevents certain substances from freely entering the cell, while it allows other substances to enter through one of two routes. One mode of transportation is through protein channels built directly into the cell membrane. For example, the sodium potassium pump controls the flow of sodium and potassium into and out of the cell. The cell is constantly trying to establish a concentration gradient between sodium and potassium, so this pump is constantly working. In order for this pump to function properly, there needs to be a healthy supply of ATP (Adenosine Triphosphate). This is why it is essential to live a lifestyle that encourages healthy mitochondria, as they are creators of ATP.
The reason these transport pumps require so much energy is that they are working against the concentration gradient and the electrochemical gradient. The concentration gradient is the concentration of various molecules on either side of the cell membrane, whereas the electrochemical gradient is the difference in electrical charge on either side of the cell membrane.
Another form of active transport is known as Cytosis, literally meaning cell action. There are two kinds of cytosis: Endocytosis and Exocytosis.
When the cell needs to move materials from inside of the cell to outside of the cell it is known as Exocytosis. This process is also known as vesicular transport and occurs when a substance is secreted into a vesicle. A vesicle is a transport molecule made up of phosopholipids that contain the material that is being transported. The vesicle makes its way to the cell membrane, at this point the bilayers rearrange and fuse with the cell membrane, allowing the substances to escape into the environment outside of the cell membrane.
When materials are needed inside the cell, this action happens in reverse and is referred to as Endocytosis. An example of this is Phagocytosis, where a cell literally consumes the material. We see this with white blood cells devouring foreign invaders. Pinocytosis is similar, where the cell membrane folds in on itself and forms a vesicle. Cells can also form vesicles through Receptor-Mediated Endocytosis. This process is activated when specific receptor proteins connect with the molecules they are designed for. See more on Cytosis from John Munro.
The Plasma Membrane – Dr. Marilyn Shopper
Endocytosis Exocytosis – John Munro
- Compare characteristics of the 4 tissue types
There are four different tissue types that make up all tissue in the body. Let’s examine them:
Epithelia are the sheets of cells that cover exterior surfaces of the body and protect the internal cavities within the body. They also make up the secretive glands and ducts, and are also found within certain sensory organs such as ears and nose. There are five categories of epithelial tissue.
The Protective Epithelium are the cells that are exposed to the environment, such as skin and lining of our mouth. These cells are tightly connected (think brick wall) in order to prevent potentially damaging substances from getting into the blood stream.
Ciliated epithelial tissues are found in the lubricated parts of the body, such as the nose, throat, upper respiratory system, and the female reproductive tract. These tissues are covered in cilia, which allows fluid to move across the surface of the tissues. Ciliated epithelium allows for the removal of foreign particles that would otherwise damage the tissues if they were exposed. For instance, mucus in the lungs help trap bacteria and get it out of the body.
Exchange epithelium is found in the lungs and the lining of blood vessels. This tissue type allows for easy access of molecules. The lungs and blood vessels are porous so that oxygen and carbon dioxide can flow freely into and out of tissues. This explains why the upper respiratory must be protected with a coating of mucus and prevent foreign matter from getting into the lungs where it will have easy access to the blood stream. Another reason why it is ideal to breathe through your nose and not through your mouth!
Secretory epithelial tissue are complex tissues that make up vital glands. These glands produce either endogenous or exogenous secretions which are used throughout the body in a variety of ways. Exocrine (think external) glands produce secretions into the body’s external environment via ducts that connect to the tissue surface. For instance, sweat glands, saliva glands, mammary glands, the liver and pancreas are all examples of glands that produce substances which are essential to the human organism. Endocrine (think internal) glands are glands that do not have ducts but instead secrete hormones directly into the blood.
Transporting epithelium is tissue that makes up the digestive tract, the intestines and kidneys. These tissues are made up of tight junctions that prevent movement between cells. These tissues must be tightly bound in order to prevent food particles and other substances from improperly leaking into the blood stream and wreaking havoc. We can see that the erosion of this tissue results in issues like Crohn’s Disease, Leaky Gut Syndrome, or other painful digestive diseases.
Connective tissue is what gives us structure and is therefore incredibly important. Our connective tissue is made up of blood, bone, fat, and proteins. These tissues are fibrous in nature and act as a sort of scaffolding which gives the organism shape and definition. I tend to think of this tissue similarly to the skeletal structure of a skyscraper, in that it is designed to be both strong and rigid, but also flexible enough so that it can bend and flex in order to sway with the wind. This type of thinking always makes me think of the old saying it is better to be like the Willow which can bend with the wind, than the Oak which is stiff and will break in a strong windstorm.
Muscle tissue is what allows us to run and jump! This tissue is able to contract and produce force. There are voluntary muscular contractions and involuntary contractions. Cardiac muscle in the heart operates in an involuntary fashion, although there is some research that shows we can control our heart rate. Smooth muscle and skeletal muscle operate voluntarily (for the most part).
Neural tissue is made of neurons and glial cells. Neurons are found most heavily in the brain and spine, but they are found everywhere in the body. Neurons communicate with each other through electrical signaling. When we choose to use our muscles in a given way, our brain first has to send the message to the muscle, which then responds to the message. More recently we are seeing an increase in neurodegenerative diseases like Multiple Sclerosis, where the degeneration of the myelin sheath (protective layer that covers the axon of the neuron) prevents the message from being properly received. This is often compared to the copper wiring that runs through any electrical system. As long as the wiring is covered with a protective coating, there are no problems, but if the protective coating deteriorates then the bare metal could possibly touch and the electrical signals could be crossed, causing all kinds of problems. In the human being, this can make daily movement, speech, or even the involuntary processes of life difficult. Many herbs and natural substances can be utilized to lessen the symptoms of MS or even slow or reverse the degradation the Myelin Sheath.
- Explain the importance of this modules material in the study of herbal medicine.
Clearly it is important for herbalists to have a clear comprehension of human physiology. It is not enough to know which herbs are good for which ailments, we have to know the why and the how. The better we understand the physiological processes of the human body, the better we will be able to choose and apply the correct herbs for specific clients.
For instance, an inexperienced herbalist might recommend Echinacea because they have heard it is good for colds, but do they understand why it is good? Do they understand the circumstances in which this herb might not be a good choice and instead long term tonification might be a better choice? Does the body need immediate immune system stimulation or does it need nourishing Yin tonics which will help to build the immunity?
Studying human physiology from a holistic point of view provides us with another tool in assessing the constitutions of our clientele. Instead of strictly looking at her or him from an energetic perspective (which is critical as well) we can integrate our knowledge of physiology and begin to build a sharper image of what is happening on both micro and macro levels.