Digestion - Scientific documentary film - DVD

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The series ‘Spacetime Cube Monade’ totally captures all images unfold in time and space axis through the story with 3D cubic world. The second one features ‘Digestion’ .

  Digestion is how we take life from other things and incorporate it into our own.  The large molecules having composed other living things are broken down into smaller, microscopic molecules. Each of the epithelial cells absorb the molecules of nutrients through a thousand microvilli that make the boundary between the inside of the body and the outside. Now small molecules will be assembled into large ones, creating new life in our human bodies.

  Now let’s see details of the digestion process, making full use of microscopy.  Why the stomach never digest itself, and why the stomach digests only food?  Why does the small intestine need to be so long? In our body, many cells are turning over continuously, and the sloughed-off cells of our own bodies are broken down and digested.

  Receipt of taste and odor information triggers selection of nutrients to take into the body.  The autonomously acting digestive tract has individual neuron system and net working among cells. There are our immune system and symbiotic bacteria in the human digestive tract.  When we look at the digestive tract in this way, we recall evolution of creatures. The digestive tract calling this second brain may be the first home of our mind.

• DVD « Spacetime Cube Monade 02 : Digestion » 
• Editor : ICAM Co., LTD
• Director : Jun’ichiro Takeda
• Details : DVD 43 mn, French & English version
• Price : 19,90€
• Published : 2011
• ISBN : 978-4-900960-30-5

Extracts from narration text of« Spacetime Cube Monade 02  Digestion »

(Chapter 1 : Digestion and Absorption – external to the internal -)
Digestion is how we take life from other things and incorporate it into our own.   From the gullet to the stomach. Proteins are mainly digested in the stomach.They are first broken down by gastric acid, then further dissolved using digestive enzymes. Food then proceeds from the stomach to the duodenum. This black liquid is called bile. It contains bile acid, produced in the liver, and digestive enzymes, produced in the pancreas to break down carbohydrates, lipids and proteins. The exact composition of the bile varies according to the food moved from the mouth to the stomach. From the duodenum to the small intestine: This is where absorption occurs.The large molecules having composed other living things are broken down into smaller, microscopic molecules. Proteins that consist of chains of some 10,000 amino acids are reduced to molecules of just a few amino acids.Inside the small intestine, which encloses the outside environment, the mucous membrane is tightly packed with tiny fingerlike villi.The divisions of the cells that compose the villi can be seen here, along with the capillaries that transport the absorbed nutrients. And now nutrient molecules dive for the first time to the quantum world.　　From macrocosm to microcosm: the world inside the cell.Each of the epithelial cells that absorb the nutrients is armed with over a thousand microvilli that make the boundary between the inside of the body and the outside.                                      Here enzymes break a connected two molecules apart. Single amino acids. And single glucose. When such smallest constituents cross the microvilli, the food leaves the outside world and enters the human body for the first time.                       These molecules go through the cell that is densely packed with organelles and toward the blood vessels. For each molecule, it is a long way journey.Riding the bloodstream, the molecules are transported to cells throughout the body, providing vital energy. Now small molecules will be assembled into large ones, creating new life in our human bodies.

(Chapter 2 : Digestion Process)(Stomach)
The mucous membrane of the stomach is covered in mucus.Here the mucous membrane is just fixed and viewed in an electron microscope.            It captures images of columns of mucus being launched. Breaking a pillar, we see there are holes in the middle.These are pipes of mucus, which transport gastric acid and enzymes.The gastric pits. The gastric juices are secreted from them.                                             The gastric acid, digestive enzymes and mucus all emerge from the same pores.                               The gastric pits as seen through an electron microscope.              In the threadlike gastric glands that extend through the gastric pits, a wide range of cells are arrayed.The cells secrete the mucus.                                                          The cells create the digestive enzymes.The parietal cells that produces the gastric acid, contains large numbers of mitochondria.From the resting phase to the active phase…Stimulated by hormones and nerves, the parietal cells sprout secretory glands, which use energy in the form of ATP to secrete gastric acid.Gastric acid, a strong acid with pH balance of 2 , activates the digestive enzymes. To avoid the effects of these on the gastric wall cells, they are carried through tubes of mucus and reach the space of digestion. The mucus tubes are produced each time we eat.          The mucus layer protects the gastric mucous membrane. It ensures that the protein in food is digested, while the body, which is composed of the very same proteins, is not.(small intestine)The length of the small intestine is about five meters in life and seven meters at death.The length of the small intestine varies depending on dietary habits.The abdominal cavity is able to hold such a long small intestine in this limited space because it is suspended wrapped in a layer of peritoneum called the mesenterium.　　But why does the small intestine need to be so long?          To make the structure of the villi clear, a dye is injected to the lymphatic vessels.These are the capillaries of the villi as seen through a confocal laser-scanning microscope.The lymphatic vessels are in the centers.                                           The absorbed glucose and amino acids enter the capillaries, while lipids enter the lymphatic vessels.                                                                                    The depressions that house the roots of the villi are called the crypts.                                           Cells generated in the crypt divide and specialize, pushing up the older cells.One cell divides two cells.                                             Before the cells split, DNA in their nuclei replicates. DNA molecules wrap around the protein called “histone”, and coil to form chromosomes.                                       Each cell specializes and learns its particular role from the information etched in the DNA and from its own position relative to the surrounding cells. Some cells emit mucus; others secrete digestive-tract hormones. Many become the absorptive epithelial cells that supply the microvilli, which separate the inner and outer worlds.   The cells born in the crypts play out their roles over three days, constantly keeping the villi new and fresh.Each day, each villus sheds some 1400 cells. Just imagine how may cells are sloughed off each day throughout the entire digestive tract!

(Chapter 3 : The digestive tract is the roots of human’s heart)(smell and taste)
The oldest arrangements are those most directly related to survival: the senses of smell and taste, which are activated upon contact with just a few molecules.The human senses of smell and taste have evolved directly from those of unicellular organisms at the very dawn of life on Earth.The molecules in food that generate odor are taken in by the receptors of olfactory cells. We discriminate among odors as we eat.The sense of taste operates in the same way.                             The tongue is a lump of skeletal muscle.                                           The surface of the tongue is blanketed with about 10,000 pits, bumps and papilla large and small. These are the taste buds, which detect flavor.During the seconds or tens of seconds that food is held in the oral cavity, people taste it and enjoy its crunchy texture through the chewing process.The flavor-bearing molecules in food are dissolved in water, filling taste-bud pores just one two-hundredth of a millimeter across.During that brief interval, flavor molecules are captured by the receptors and ion channels on the tips of the microvilli of the taste cells.(autonomy of the digestive tract)By what pathways does the autonomously acting digestive tract relay information? 　Here dye is applied to the nerves to illustrate.Stomach nerve cells are dyed red.                                              The bodies dyed green are the interstitial cells of Cajal. These connect the nerves to the skeletal muscle.Alternately constricting and relaxing, the segmentation movement of the small intestine reduces the contents to smaller pieces.In the small intestine, Auerbach’s plexus extends between the ring muscle and longitudinal muscle.                                                   Nerve ganglia are bundles of nerve cells. Extending from them in a fine mesh, the interstitial cells of Cajal serve as the pacemakers for autonomous actions.Also, the interstitial cells of Cajal, which are inside the ring muscle, run parallel to the neurons, receiving the transferred substances and passing them on to the smooth muscle.            Meissner’s plexus, immediately inside the ring muscle, is in contact with Auerbach’s plexus.Peristalsis in the large intestine moves the material onward in a single motion.Auerbach’s plexus completely covers the ring muscle in the large intestine.                  Some one hundred million nerve cells in the digestive tract direct the movements of the digestive tract as an autonomous nervous system.    Recently, the digestive tract has been called as a “second brain.”The stomach, small intestine and large intestine each possess a network of nerves and interstitial cells of Cajal, which direct the motion of skeletal muscle.    But that’s not all.     (symbiotic bacteria)The human digestive tract plays host to hundreds of species of symbiotic bacteria. These bacteria compete with each other, maintaining balance and creating intestinal flora unique to person to person.These intestinal flora continually vary with the foods eaten and the physical condition of the individual. The large intestine contains a hundred trillion of enterobacteria, weighing a total of about 1.5kg.Plicae of the transverse colon, where the flow of substances often stagnate, provides comfortable shelter for enterobacteria.Butyric acid and acetic acid produced by the bacterial flora are absorbed, providing energy for the epithelial cells in the large intestine.The enterobacteria decompose dietary fiber that human digestive enzymes cannot digest, acquiring nutrients and energy and creating substances on which human life depends. The vitamin B complex and vitamin K are also produced in this way.Symbiosis can be thought of as a contract between the enterobacteria and their host the digestive tract. It is a judicious balance of economic interests between the bacteria and their human host.One day long ago, the first multicellular organism was born. With the emergence of the digestive tract, these creatures continued to evolve.  Over millions of years, the enteric nervous system evolved into those of the vertebrates, with brains and spinal cord.Eating to live and eating offers human the will to live. Foods bring joy and delight. Sometimes our stomachs turn, making us agonize over mortal danger. Our spirit seems to make its first home in the digestive tract.