Origin of Small Intestine
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Animals which only have intestines, mouths and tactile sense, like sea anemones
is called “ Coelenterata “
They have a simple body structure that
“ Body = Intestine “
There is a mouth to intake food and that functions as a poophole, however its intestine is very smart.
There are " sensor cells "
in the intestine that check
what kind of food entered and chemically recognize the contents, then react.
They also release the hormone and tell the information that “ what kind of food they got " to the cells and the nerves nearby.
The neuron sends a signal to another cells which decompose (digest) and absorb each contents in there.
In the evolutional process, the nerve cells that surrounded the intestine for protection that has formed a spinal cord and its tip is swelled up to become a brain.
The basic structure of the intestine and the functions haven’t been changed so much in the process, the intestines of sea anemone is almost same as human being has, the sensor cells of antennae has became "taste buds" which feel the taste on the human tongue.
The sensor cells, and the nerve cells which make the network like a fishnet and those cells govern all functions of the Small Intestine of human body, so It is the organ that can conduct all functions by itself without receiving any brain command.
“ Our body is made of what we have or eat “
There is the "intestine" at the very beginning in the human evolution and even in the process of growth of a baby, which is indispensable for living organisms to live.
Functions of Small Intestine in Anatomy
The small intestine is a muscle tube of more than 20 feet in length, accounts for about 80% of the digestive tract. From the top it is divided into three parts: Duodenum, Jejunum, Ileum
Approximately 100 million Nerve cells (it's more than 15 billion in the brain, though) exist and govern the unique nervous system that maintains Digestive system, Immune system, Endocrine system and the blood flow.
* Nerve cells: Cells that can exchange information with
electric signals and neurotransmitters *
Decompose Proteins into Amino acids, Fats into Fatty acids, Carbohydrates into Glucose, Absorb those nutrients from the Villus
• Govern about 60% of the Immune system of the body
Mucosal immunity: Prevent invasion of bacteria, viruses, etc.
Recognize which bacteria or virus is harmful or safe
Intentionally takes bacteria and virus from Peyer’s Patch into the lymph to investigate whether and where any infection occurs or not in the entire body, then get rid of it if it does
• Produce and secrete serotonin
Approximately 90% of the serotonin in the body is produced and secreted in Mucosa of the Small Intestine and with Intestinal Chromaffin Cells
When the brain feels stress, serotonin and its receptor bind together that leads
to hyperactivity of Peristalsis (Irritable Bowel Syndrome)
Promotes peristaltic motion, but also prevents Osteoporosis by suppressing its secretion
< < < What is Serotonin? > > >
One of the neurotransmitter, 90% of that exists in the small intestine, 8% in the blood vessels, 2% in the brain,It also works as a hormone for digestive system,
mood (anxiety and fear), stress tolerance, sleep-wake cycle,
hemostatic action to coagulate the blood of
the cardiovascular system,
cognition and control of pain,
controlling appetite,
euphoria...
and limiting bone resorption
When we eat, the feeling calms down because most of it exists in the intestinal tract
• Secretion of various digestive hormones
Incretin: GIP, GLP-1, promote secretion of Insulin secreted from the pancreas
Secretin: neutralizes acidic porridge of the food, which was sent from the stomach, suppresses secretion of Gastric Juice
Cholecystokinin: promotes the secretion of Pancreatic juice and Biliary excretion
< Helps and governs some of Gallbladder’s, Pancreas’s and
Stomach’s functions in the digestive system >
About 15 billion neurons send electric signals to exchange information with each other in the human brain that unconsciously affect emotion and behavior, these brain functions form as a “ Self “. It has been known that thinking, feeling, etc... are performed not only in the brain and the central nervous system but also in the recent research by the "Second Brain”. The neural circuit called Vagus Nerve where the Brain exchanges informations with parts of the body such as Vocal Cords, Heart, Lungs and Intestines when a “ Fight or Flight “ situation.
Such reactions had been thought to be sent from “ the Brain to each part ", but it turns out that 80-90% of the nerve fibers of the Intestinal Nervous System are conversely sending the signal “ the Intestine to the Brain ".
The Intestinal Nervous System controls the movement of the entire
digestive activity from the Esophagus to the Anus without being sent
instructions from the Brain, “ the Intestinal Nervous System = the Second Brain " is possible to function to respond to food even if the Vagus Nerve is broken. Since fat and sugar are energy sources for the body and the brain, the Brain releases dopamine by ingesting fat and sugar-rich foods that feels us "pleasant".
50% of the Dopamine is produced in the body, and 90% of the Serotonin is produced with Intestinal Chromaffin Cells and Intestinal Bacteria, those Hormones have major impacts
for the mood and emotions such as happiness and joy...
<Specific intestinal bacteria and neurotransmitter that produces>
Lactobacillus species: Acetylcholine, Gamma Amino Butyrate Acid (GABA)
Bifidobacterium species: GABA
Escherichia: , Serotonin, Dopamine
Streptococcus, Enterococcus: Serotonin
Bacillus species: Norepinephrine , Dopamine
I. Acetylcholine: mainly works on Autonomic Nervous System, Sweating, Peristalsis...
II. GABA: it relieves stress and calms excited nerves down, suppressing excess
secretion of Dopamine
III. Norepinephrine : awakening, fight against the crisis of life, anger, stress, attention,
uncomfortableness, balanced with Serotonin
IV. Dopamine : pleasure, joy, motivation, balanced with Serotonin
Depending on our diet, Intestinal Bacteria are determined " which Bacteria will flourish ", the flourished Bacteria send an information to the Brain through the Vagus Nerve “ What kind of foods they prefer ". That’s why there are some scientists who recommend to take probiotics or transplant feces from others into the intestine to correct overeating by removing the bacteria from the Gastrointestinal tract which prefer sugar and fat, that will decreases the person’s appetite.
Intestinal bacteria also might affect the human behavior. The bacteria haven’t flourished in the intestine of the Mice that have been bred in a sterile environment. They behave like autism and there has been a big change in the level of specific proteins involved in memory, learning and the production rate of Serotonin. However after given certain probiotics to the mice, the symptoms have been getting better, so it has become known that intestinal bacteria were controlling the behavior of Mice.
Also Mice that ingest a specific bacterium have fewer stress hormones in the blood and the ability of learning and memory were improved, but when cutting the vagus nerve of that, this improvements disappeared.
In the study has reported that people who have kept to eat probiotics yogurt for 30 days have lower levels of anxiety and depression than others who have just had milk without bacteria.
In the another study, that was for the people with depression who have resisted for antidepressants were treated by embedding a small pacemaker in the body that stimulates the Vagus Nerve with many kinds of frequencies for emulate signals of the Intestines of healthy people. ( Vagus Nerve Stimulation )
Intestinal bacteria not only interact with the hypothalamic-pituitary-adrenal (HPA) axis to form the normal structure of sleep, but there is a possibility that also have a role to counter negative emotions, to forgive others, and it may have a positive influence for giving birth and parenting.
~ references ~
http://www.wellnesswarrior.org/how_your_gut_microbes_may_be_communicating_with_your_brain
https://www.youtube.com/watch?v=T3Ftj5E90tY
Small Intestine in Oriental Medicine
It’s in Fire Element, Small Intestine is Yang, Heart is Yin
Whereas Small intestine works in unconsciously,
Heart is the organ we can feel most consciously with our own emotions
Related parts of the body : Pinky fingers, Wrists, Elbows, Shoulder Blades, Neck (side)
Sort: The digested foods and drinks sort to nutrients and waste in Small Intestine. It absorbs the nutrients and send the waste to Large Intestine. About 80-90% of the liquid is absorbed there, too. Spleen won’t be able to work if the absorption isn’t well in Oriental medicine. (this is thought as Fire element controls Earth element).
Diarrhea may occurs if Small Intestine cannot absorbs the liquid well because the rest of the liquid goes to Large intestine so the waste becomes watery, even though Large Intestine absorbs some of the liquid. So Small Intestine controls the amounts of the urine and stool.
*** The role of the Small Intestine in Oriental medicine is not so much. It seems that the Heart functions and its concept had been more important in the era, the length of human life was much shorter than now and there were much less environmental pollutions, Not so many bacterial infections had been found, etc.. Maybe because that the people had lived with nature naturally in the ancient China.***
