The diaphragm is the membrane separating the thoracic and abdominal cavities.

A membrane is a sheet-like structure that forms a boundary between one space and another. In addition, some membranes allow for passage of some things through it while excluding others. The human body has several different kinds of membranes. On a microscopic level, the contents of each cell is surrounded by a membrane called a phospholipid bilayer. Built into the cell wall are molecular gateways that control the passage of materials in and out.

I doubt, though, that the Buddha, even in his infinite wisdom, understood the mechanics of cellular biology when he recommended his monks contemplate on the 32 parts of the body as a means of overcoming sensual desire and attachment to one’s own body.

On a macroscopic level, the grosser membranes are more easily discernible. The heart, for example, is surrounded by a thin, shiny double-walled membrane called the pericardium. The visceral organs are covered in peritoneum. It also has two layers, with the outer layer serving as the lining of the abdominal cavity. The mesentery is the portion of the peritoneum that anchors the small intestine to the rear abdominal wall. The mesentery has a rich blood supply, which picks up digested food for circulation throughout the body. It is the selective nature of the peritoneum that allows for peritoneal dialysis, a process that keeps alive many people whose kidneys have failed.

We also have synovial membranes that line joint capsules and produce a lubricant called synovial fluid, and mucous membranes that line passages that connect internal organs to the external environment. Mucus secreted by the membrane traps foreign particles and aids in expelling them.

The most obvious membrane in the human body is the diaphragm. Unlike the other membranes, which are thin layers of specialized cells, the diaphragm is a muscle that separates the thoracic cavity (chest) from the abdominal cavity. It has several openings that allow for the passage of the esophagus, the inferior vena cava, the abdominal aorta, and other structures. The principle function of the diaphragm is breathing. When this muscle contracts, it pulls down on itself, increasing the volume in the thoracic cavity, thereby reducing the air pressure, which allows for the intake of air into the lungs.

This change in air pressure, which is essential to breathing, would not be possible without another membrane, the pleura. Like the pericardium and peritoneum, the pleura has two layers, one that covers the lungs and the other that lines the thoracic cavity. The two layers slide against one another, reducing friction. There is also a negative air pressure between the air-tight layers, which keeps the lungs in contact with the chest wall. If the outer membrane is torn, air will get between the layers and the lung will collapse.

Through breathing, oxygen and carbon dioxide are exchanged within body tissues. The simple act of breathing is one of the mechanisms that keeps the body alive. Mindfulness of in and out breathing is the simplest form of Buddhist meditation practice. When you train the mind to observe the breath you see that each breath is a microcosm of all that happens in the universe. What comes into existence must, eventually, go out of existence. Everything that comes into existence sets the conditions for what comes next. Change the conditions, change the outcome.

Note: For background on this series, please read the Introduction to the 32-Parts Project.

Sheep liver, courtesy Wikipedia

The liver is a vital organ (you can’t live without it) that rests high in the abdominal cavity beneath the right ribs. Although it is not part of the digestive tract, the liver is part of your digestive system.

The liver, which is also a gland, secretes bile (stored in the gall bladder) into the small intestine to emulsify fats for absorption. A true multi-tasker, the liver processes every bit of food that comes into the body, converts and stores sugars, detoxifies all manner of chemicals, and secretes a number of hormones, particularly those involved with blood clotting.

The liver has two blood supplies. One brings oxygenated blood from the lungs through the hepatic artery. The other brings blood containing digested food directly from the small intestines through the hepatic portal vein.

The liver is easily damaged by overuse of alcohol and drugs and other chemicals. Liver failure can be a slow process that can go unnoticed for a long time or it can happen within hours. Eat the wrong kind of mushrooms, and, if a donor isn’t found within hours, death is immanent. Liver transplants have been done since 1963 and the procedure is one of the most expensive. The liver is the only internal organ that can regenerate itself. A new organ can grow from as little as 25% of tissue.

Note: For background on this series, please read the Introduction to the 32-Parts Project.

Human heart. Photo courtesy Wikipedia

“Buddhism is all about being in the head,” my friend said. “Sufism is about being in the heart. It’s about love.” The conversation focused on the various differences between the two spiritual points of view, and my friend insisted that because Sufism was heart-centered instead of mind-centered it was superior. I tried to explain that Buddhism makes no distinction between the heart and mind as emotional centers in a human being. They are the same thing and are sometimes referred to as the heart-mind. My argument made no impression.

Her confusion is easy to understand. Thinking – an activity of the mind – feels as though it takes place in the head, where the brain resides. If it feels that way today, surely it must have felt that way to every human ever capable of conjuring a thought.

Emotions, however, seem as though they emanate from the viscera. If feelings of passion cause an increase in heart rate, the heart certainly must be center of love and all the other emotions that swirl around it. We use terms like “gut feeling,”  “butterflies in the stomach,” and “visceral response” to express other feelings that do indeed seem to have an origin in places other than the brain. This is as real for us today as it must have been for our forebears.

As the study of anatomy evolved and the physiology of nervous system explored, the part of the nervous system that controlled the the viscera was isolated and termed the autonomic nervous system. Even on a scientific level, there was a time when control of the visceral organs was thought to be autonomous (separate) from the brain. Further study has revealed that the autonomic nervous system is not a separate system of control. Rather, it is a complex branch of the peripheral nervous system. The peripheral nervous system is outside of – but connected to – the central nervous system of the brain and spinal chord. The endocrine (hormone) system exerts powerful influence over the autonomic nervous system and the organs – most notably the heart. It’s no wonder the heart has the reputation as the center of love.

However, the heart is just another part of the physical form of the body. It is the primary component of the circulatory system, which also includes arteries and veins. The circulatory system transports blood (Part 23) throughout the body. The heart is a muscle, but it is unlike skeletal muscle (Part 6). It is self-stimulating on the whole, and it’s fibers are interconnected and capable of stimulating those adjacent to it to maintain its characteristic beat.

The heart’s structure is that of a pump. It’s job is to rhythmically contract to keep the blood flowing. Although the heart is self-stimulating, its rhythm and force are regulated by a number systems in the brain. It will beat faster and more forcefully – thereby circulating more blood per minute – when dictated by other bodily needs and desires.

The beating heart, like the ever-present breath, is a constant reminder of life within the body. It is a worthy object of meditation as one beat leads to the next in a constant flow of beginnings and endings. Each one of us has a heart, regardless of our mental states. Contemplating what will happen when a heart – anyone’s heart – stops is an exercise that may lead to insight into the true nature of things.

For background on this series, please read the Introduction to the 32-Parts Project.

A platter of lamb kidneys, courtesy Wikicommons

My grandfather on my father’s side died not long before I was born. He had seven children – five sons and two daughters, not counting the baby who died. My grandfather died of kidney failure. He had a progressive and incurable genetic disorder called polycystic kidney disease. With this disease, the kidneys are slowly overtaken by fluid-filled cysts. The kidneys get larger and larger and less and less functional. Without at least one functional kidney – or an artificial means to perform the organs’ duties (dialysis) – the body cannot get rid of excess fluid and wastes. The body becomes more and more polluted, and, over time, it will die.

Genetics is a field of study I comprehend only slightly, certainly not enough to explain how this disease is transmitted from one generation to another. Yet I do know that if one parent has it there is a 50 percent chance that each offspring will have it, generation through generation.

Polycystic kidneys, courtesy Wikicommons

In this regard, I am a lucky man. My father did not inherit the gene for polycystic kidneys. One of my uncles and both of my aunts, however, did. And so did several of their children, my cousins. The uncle and aunts have had kidney transplants – but not after years of increasing suffering through various aspects of the disease. Several cousins also have had transplants. One of them had a kidney that had grown to the size of a newborn baby and weighed ten pounds.

Kidneys are paired organs, each about the size of a clenched fist. They are located in posterior portion of the abdominal cavity approximately in the area of and protected by the lower two ribs. The functional unit of the kidney is the nephron. Each kidney contains up to a million nephrons. Blood is filtered through the nephrons. Everything in the blood except the red and white blood cells is removed. Then – through the magic of chemistry, osmosis, and semi-permeable membranes – the nephron returns to the blood all the chemicals and water the body needs. What’s left behind is urine.

Not everyone is born with two kidneys. Sometimes, they are joined into what is called a horseshoe kidney. If one had a horseshoe kidney, one wouldn’t know it without some sort of definitive exam – ultrasound or MRI, for example. Or surgery.

One normal kidney is sufficient to do the job, which is good for those who are fortunate enough to find a donor for transplant.

For background on this series, please read the Introduction to the 32-Parts Project.

Bones form the structure of the human body. They are comprised mostly of calcium and phosphorus, minerals that remain in place long after death and the breakdown of other tissues. Bones also protect sensitive organs and serve other functions as well. One of those very necessary functions is to provide the environment for marrow, without which human life would be impossible.

Bone marrow is a gelatinous substance that resides within the hollow core of a bone. There are two types of marrow, red and yellow. Each type is predominate in certain kinds of bones and in specific areas of them. In the newborn, all marrow is red. As the person ages, some red marrow converts to yellow until, in an adult, there is about 50 percent of each.

The cells of each kind of marrow have the capacity to do what cells of other mature tissues do not. Throughout one’s life, cells divide according to the genetic code in their DNA. A single skin cell will divide in two to become exact, specialized duplicates of the original. Liver cells do this, as do bone cells, stomach cells, and so forth. Specialization begins in the developing fetus with a process called differentiation.

At conception, the first cell is undifferentiated. It is unspecialized with no purpose other than to divide again and again. It’s a cell with lots of potential. It’s a cell from which all specialized cells will derive, eventually. It’s a stem cell. During gestation, as cells divide, they gradually differentiate and become fixed as a specific kind.

Bone marrow cells are undifferentiated. They, too, are stem cells. However, unlike embryonic stem cells, which can become any other kind of cell needed by the body, marrow stem cells have limited destinies. The cells of red marrow will differentiate into red blood cells, platelets, or one of several kinds of white blood cells. The cells of yellow marrow can become bone cells, cartilage cells, muscle cells, or fat cells.

A number of diseases can be treated with a bone marrow transplants. Marrow can be harvested from a healthy individual – usually from the hip bones – and transplanted into the circulatory system of someone who has undergone chemotherapy (which kills rapidly dividing cells  – cancer cells as well as healthy cells). Once in the blood stream, it will find its way into the bone where it can begin making new, healthy cells. Bone marrow also can be harvested from and reintroduced into the system of the same individual.

Stem cells also are used in research to find cures for irreversible diseases like Parkinson’s disease. Controversy surrounds the use of embryonic stem cells.

The four-minute video below compares a new way of harvesting marrow with the way it’s been done for many years.

For background on this series, please read the Introduction to the 32-Parts Project.

Human Remains, Wikimedia Commons

When I was 11 years old, I had what may have been my first real moment of insight. I was in fifth grade at a Catholic elementary school in Portland, when I slipped out onto the playground ahead of the rest of my class. I can’t remember why I was out there alone – perhaps I didn’t have to go to the bathroom, where the rest of my classmates were herded before recess. This was 1962, and the Sisters of the Holy Child maintained the strictest order to ensure that all God’s children in their care would eventually be herded into heaven.

Whatever the reason for my being separated from my classmates and teacher, there I was clambering up the metal bars of the the play structure at the farthest corner of the asphalt playground, alone. Near the top, I reached out for a bar but lost my grip. In an instant, I hit the ground, stunned by the pain that came from my right arm near the wrist.

The playground now swarmed with kids. I sought out my teacher to tell her I’d hurt myself. “That’s what you get for coming out here before everyone else,” she said. When I insisted that it hurt, she told me I had a sprain and sent me to another nun who, she said, used to be a nurse. The nun who used to be a nurse told me to run cold water over it. At a water fountain, my left hand twisted awkwardly around the handle and my right arm under the meager trickle, I did what I was told. It didn’t help.

I noticed my arm had a slight S curve to it. I considered the situation, hearing in my memory the snap when I hit the ground. I’d heard of people breaking arms and legs. But before this moment, I hadn’t understood what it meant. I’d figured that having a broken arm was something like having doll with a broken arm. There were two pieces: the doll in one hand, the arm in the other. Now, no one needed to explain it to me. The bone inside my arm was broken, and I knew it.

Eventually I made it into the office. My mother was called, and off we went to the hospital.

By definition, a bone is an organ, although it’s not usually what comes to mind when we think of organs. The 206 bones in an adult human make up the skeletal system, the framework of the body. Our bones serve more purposes than providing structure and support, however. Bones protect the brain and spinal column and the contents of the thoracic, abdominal, and pelvic cavities. Muscles and tendons work with the skeleton to create movement. Tiny bones in the ears allow for hearing and the bones of the skull enhance the the sounds we hear and give resonance to our voices.

Bones are a storehouse of calcium and phosphorus. Through the marrow within them, bones are the site of blood cell production. (Marrow and blood are separate categories in the contemplation of the 32 parts of the body and will be discussed later.)

Bones are comprised of living cells and the non-living mineral calcium phosphate. Like other tissues of the body, bones grow through the process of cellular division. In addition, and unlike other tissues, specialized cells called osteoblasts create a protein mixture that mineralizes into the solid structural component, bone. Other cells – osteoclasts – break down bone tissue to release calcium and phosphorus into the bloodstream. Bones go through an ongoing process called remodeling. Our bones – like everything else – are constantly changing. On the molecular level they come into and go out of existence day after day, just as each breath does.

Bones, being mostly inorganic calcium phosphate, remain long after the once living tissues of the body decay after death. The skeleton, or some parts of it, is a symbol of death. The skull and crossbones is the universal symbol for poison. Some pirates used it as a symbol on their flags – the Jolly Roger – as a means of frightening their victims into surrender. Not doing so was certain death.

Skeletons make popular Halloween costumes and play a prominent role in Day of the Dead celebrations in Mexico (these two religious holidays are related).

Sometimes, while lying next to Robin, I feel her bones. There is a skeleton beneath her skin – skull, ribs, vertebrae, tibiae, pelvis, etc. Her bones hold her up, allow her to move through space, and to touch me back. Someday, though, they will not. Nor will mine.

Surrendering to the inevitable – and not clinging to what is impossible to hold for long – is the purpose of contemplation of the 32 parts of the body.

For background on this series, please read the Introduction to the 32-Parts Project.

Sinew is an Old English word that means tendon. Tendons are made of strong, elastic fibrous connective tissue that connects muscle to bone. The similar material that binds bones together is a ligament.

Each long, slender muscle fiber (an individual cell) is sheathed in connective tissue. Muscle fibers are bundled into fascicles, also sheathed with connective tissue. Fascicles are bundled into muscles by the same stuff. All these casings extent beyond the muscle proper, become tightly packed together, and then blend with the material that forms the outer layer of bone, the periosteum. When a muscle contracts, it exerts its force through the tendon to the bone. The bone moves around its joint.

When I was a kid, I was given a leg of a freshly killed chicken to play with. My father showed me how to pull on the tendons to make the claws open and close.

Tendons are comprised of fibrous bundles of the protein collagen, a nonliving substance manufactured by living cells called fibroblasts. Live cells need a constant blood supply, but nonliving cells do not. Most of the substance of a tendon is nonliving, so tendons are not highly vascularized (not many blood vessels in them). This helps explain why injuries to tendons and ligaments take such a long time to heal since it is the constant flow of blood that promotes healing.

Because of the high tensile strength of tendons, animal sinews have been used throughout history as a source of thread and cordage to lash things together. It also has been used to reinforce hunting bows.

For background on this series, please read the Introduction to the 32-Parts Project.

]]> http://paulgerhards.com/blog_thisisthatis/2009/05/21/part-7-sinews/feed/ 0 http://paulgerhards.com/blog_thisisthatis/2009/05/04/part-6-flesh/ http://paulgerhards.com/blog_thisisthatis/2009/05/04/part-6-flesh/#comments Tue, 05 May 2009 03:07:40 +0000 Paul http://paulgerhards.com/blog_thisisthatis/?p=1161 Note: For background on this series, please read the Introduction to the 32-Parts Project.

From the collection of anatomical drawings by Bernardino Genga (1620 — 1690), courtesy Wikimedia Commons

Getting to the meat of it, the sixth part of the Meditation on the 32 Parts of the Body is flesh. Flesh is muscle, the most abundant tissue in the body. The body has three kinds of muscle tissue. Cardiac muscle keeps the heart pumping throughout a person’s lifetime. Smooth muscle lines the veins, arteries, intestines, stomach, bladder, and various other organs and vessels. Cardiac and smooth muscle are responsible for moving substances through the body. They contract involuntarily, and we have no direct control over them.

Skeletal muscle gives power to the body, allowing it to move. The contraction of skeletal muscle is voluntary. That is, we can exert conscious control over our flesh, although it may not always seem so. Sometimes the voluntary control over our muscles is overridden by the nervous and endocrine (hormone) systems. Skeletal muscle also helps keep us warm. About 85% of body heat is generated through muscle contraction.

Muscle moves the body through contractions stimulated by the nervous system. When a muscle contracts it applies force to bones, which are linked together in a series of joints. While the nervous system – inspired by our thoughts to move – is stimulating muscles to contract, it also is inhibiting the contraction of other muscles. If all muscles contracted at once and with equal force, we’d be unable to move at all. So with every movement of a normal body, there is complex coordination of muscle contraction and relaxation.

As a person ages, muscle mass and strength diminish, impairing movement. In my own body I notice subtle (and sometimes not so subtle) changes in my ability to do things. Some chores have become more difficult merely because I don’t have the strength I once had to do them.

One of my occupations is that of licensed massage therapist. I work directly on the muscles of others, young and old. I also teach classes in kinesiology – the science of human movement – to students interested in pursuing that career. I’ve had several opportunities to visit a cadaver lab and examine at hand the muscles of the body.

Clinical studies aside, examining a cadaver is a good opportunity to contemplate a body that has lost its life. As we all will.

For background on this series, please read the Introduction to the 32-Parts Project.

]]> http://paulgerhards.com/blog_thisisthatis/2009/05/04/part-6-flesh/feed/ 2 http://paulgerhards.com/blog_thisisthatis/2009/03/13/parts-1-5-the-double-ended-bag/ http://paulgerhards.com/blog_thisisthatis/2009/03/13/parts-1-5-the-double-ended-bag/#comments Fri, 13 Mar 2009 14:39:05 +0000 Paul http://paulgerhards.com/blog_thisisthatis/?p=1066 Bag of Bones is the title of a novel by Stephen King. The title evokes what one would expect from King, whose forte is writing detailed accounts of all things bloody and creepy. The phrase “bag of bones,” of course, didn’t begin with King. It’s been around a long time as a useful means of describing an emaciated person or animal or just someone old and creaky.

Thinking of the body as a bag goes back at least to the Buddha, who sometimes described it as a double-ended sack made of skin and filled with all manner of things, not just bones. He compared the body to an ordinary bag with two ends filled with various grains and beans. Pouring out the contents, a knowledgeable person would be able to distinguish this  grain from that bean. In the same way, a contemplative person would recognize his or her own body as being a collection of things, useful to the whole but undesirable in and of themselves. The Buddha instructed his followers to be mindful that the body was nothing special, just a collection of parts. The parts of the body – 32 of them – become objects of meditation.

Furthermore, the monk reflects on this very body from the soles of the feet on up, from the crown of the head on down, surrounded by skin and full of various kinds of unclean things: ‘In this body there are head hairs, body hairs, nails, teeth, skin, flesh, tendons, bones, bone marrow, kidneys, heart, liver, pleura, spleen, lungs, large intestines, small intestines, gorge, feces, bile, phlegm, pus, blood, sweat, fat, tears, skin-oil, saliva, mucus, fluid in the joints, urine.’ Just as if a sack with openings at both ends were full of various kinds of grain — wheat, rice, mung beans, kidney beans, sesame seeds, husked rice — and a man with good eyesight, pouring it out, were to reflect, ‘This is wheat. This is rice. These are mung beans. These are kidney beans. These are sesame seeds. This is husked rice’; in the same way, the monk reflects on this very body from the soles of the feet on up, from the crown of the head on down, surrounded by skin and full of various kinds of unclean things…

MN 119, Kayagata-sati Sutta

The first five parts of the body – head hair, body hair, nails, teeth, and skin – are the bag and its accessories. The outer parts are what we present to the world. We identify with these parts because they are how we identify ourselves to others. We spend much time and money on these parts, and not always out of necessity. We strive to make ourselves more appealing to others and at the same time distinguish ourselves from them. There are other psycho-social reasons, too, but but I don’t want to wander further into the realm of psychology.

The next 12 parts of the body comprise the solid matter within our double-ended bag of skin. They are seen rarely by anyone except those who would  repair a wound or address an illness. We don’t think too much about these parts unless we are ill or broken. The exception is muscle (flesh), because well-toned muscle enhances the overall appearance of the bag of skin that surrounds it. We give a lot of attention to muscle.

The remaining parts (with the exception of the brain) are produced by the other parts. Most of these parts we take great care to conceal. Sometimes they  come out at unexpected times, often to our great embarrassment.

Note: If you are here for the first time, please take a moment to read the Introduction to the 32-Parts Project in the sidebar for background information.

]]> http://paulgerhards.com/blog_thisisthatis/2009/03/13/parts-1-5-the-double-ended-bag/feed/ 0 http://paulgerhards.com/blog_thisisthatis/2009/03/07/part-5-skin/ http://paulgerhards.com/blog_thisisthatis/2009/03/07/part-5-skin/#comments Sat, 07 Mar 2009 23:53:48 +0000 Paul http://paulgerhards.com/blog_thisisthatis/?p=1020 Note: For background on this series, please read the Introduction to the 32-Parts Project.

The other day I visited, for the first time, a dermatologist. I have on my skin a small collection of questionable areas that needed examination. Nothing serious, but potentially cancerous. He prescribed a chemotherapy-like cream for that crusty spot on my scalp caused by too much sun exposure. Those barely perceptible blotches on my right forearm were most likely caused by the use of epoxy resins during my canoe-building days. The doctor used a scalpel with a short blade and green handle to slice off the actinic keretosis which had been on my left forearm for a year. He sent that off to the lab for questioning. I’ll know the results of the investigation in a couple of weeks.

The skin is an organ of the  integumentary system, which also includes hair, nails, and sweat and glands. Most people don’t think of skin as being an organ – not like the the stomach, liver, and kidneys – but it is. Like many of our our organs, it’s one we can’t live without and has many important functions. The skin, among other things:

• Maintains body temperature
• Guards against water loss
• Detects changes in environment
• Begins vitamin D synthesis
• Excretes water, salt, and some wastes
• Protects against the elements, pathogens, and other harmful substances
• Participates in the immune system
• Is the boundary between me and not-me*

The skin is made of two layers. The deepest and thicket layer is the dermis. Within the dermis are blood and lymph capillaries, nerve endings, hair follicles, and oil and sweat glands. All these are held within a matrix of  connective tissue, which is in part composed of elastic fibers.

Above the dermis is the epidermis. The epidermis is much thinner than the dermis and consists of four layers (the palms and soles of the feet have five layers). The deepest layer of the epidermis is a single layer of squamous cells called keratinocytes. This layer also contains melanocytes, the cells responsible for skin pigmentation. As the keratinocytes reproduce, older cells are pushed outward, dying slowly as they move closer to the surface. As they move outward, they flatten and fill with the protein keratin. They also secret a waterproof lipid (fat). The outermost layer of the epidermis is the corneum, which contains about 30 layers of dead, fully keratinized cells. These cells are constantly sloughed off. Dead skin cells are are the primary source of food of the house dust mite. Estimates indicate the average body sheds 40 pounds of epidermis during a lifetime at a replacement rate one new layer each month. That’s a lot of dust-mite chow.

It seems reasonable to think that with a new layer of skin each month one’s skin would forever look new and fresh. Not so, because aging takes its toll, as does exposure to sun and wind and myriad contaminates and chemicals. Maybe someday this aging process will be reversed by even greater strides in technology, but not today. As the body ages, blood flow to the dermis decreases, the dermis and epidermis get thinner and become more and more fragile. The skin’s ability to heal itself diminishes.Even small wounds take longer to heal and so are more susceptible to infection. The skin also loses its elasticity with age. It sags and bags under its own weight.

Various skin cancers notwithstanding, there are hundreds and hundreds of things that can go wrong with the skin from acne to zygomycosis. My own skin problems – which are relatively mediocre – are nothing unusual for skin of my age. It has begun to wrinkle and sag. It gets blotchier by the day. The skin on my neck looks like that of a plucked chicken. I can expect more actinic keratoses as the years go by. The breakdown of my skin is part of the process that began at birth, nearly 58 years ago.

As an object of meditation, that’s a lot to contemplate.

*This is moot because the discussion of auras, energy fields, and odor and other molecules and waste products that emit from the body, etc. is not to the point.

Note: For background on this series, please read the Introduction to the 32-Parts Project.