First, what is the meaning of innervation? Innervation, as defined by Audio English. net, is defined as:
1. The neural or electrical arousal of an organ, muscle, or gland.
2. The distribution of nerve fibers to an organ or body region.
Innervation of the Bowel
There are roughly one hundred million, tiny neurons that make up the “brain” of the peripheral nervous system ( also called the enteric nervous system) in the bowel. The enteric nervous system runs the autonomic functions,(the functions that can’t be controlled), and are housed throughout the internal walls of the bowels. The afferent pathways of the bowels are the structures that allow for irregular, autonomic, impulses stemming from the intestines. The autonomic impulses then migrate to a central nerve such as the central nervous system. The afferent pathways, likewise, have small fibrous nerves that communicate the autonomic impulses with the delicate spinal cord and the brain. When put in simpler terms, the afferent pathways act like a telephone line for the afferent nerves to “talk” to the command center of the body. Information regarding innervation of the bowel may be further studied at www.webmd.com.
The blood supply to the bowels comes from branches of the arteries known as the superior mesenteric artery, and the inferior mesenteric artery. Another artery is present as well, and serves as a “merger” for the two main arteries. This particular artery spans the entirety of the bowels and is perpendicularly placed.
What Makes the Bowels Function
The bowels belong to the bodily system known as the digestive system. All processes of the bowels begin with the intake of food and liquids by either oral means, intravenous means, or feeding tubes.
* Oral- Food such as meats, fruits, pasta., milk, and green beans.
* Oral- Liquids such as water, juice, soda, and tea
* Intravenous- intake is through a vein or artery and includes nutritional means such as trace elements, fats, vitamins, and dextrose. Placement of the I.V makes a difference in the amount of nutritional absorption the body receives. If an intravenous line is inserted through a vein in the arm or hand, the body will absorb less intake than if it were placed in a central site such as an artery.
* Feeding tubes- either by NG-tubing ( Nasogastric tube introduced into the stomach through the nostril ), J-tube (tubing that is surgically inserted through the skin and directly into the jejunum of the small intestine), G-tube ( steril tubing that is surgically placed through the skin and into the stomach ). Minerals, vitamins, fats, and water reach the digestive system ( bowels ) in a liquid form. There are additional feeding methods that employ the use of a feeding tube such as syringe feeding, gravity drip, and pump feeding. All matters pertaining to any kind of tubal nutrition route need to be discussed with a physician for information about proper care, feeding instruction, and questions about risks and benefits of using a tubal feeding method.
Anatomy of the Bowel
The remarkable system is comprised of several organs working in unison to remove wastes from the body, and to absorb key substances that the body needs such as vitamins, nutrients, and water. The mouth, esophagus, and stomach are par for the course of the digestion process leading into the bowels. There are a vast number of veins that supply much needed nutrient-rich blood to the bowels. The parts that make up the bowels are:
* The colon ( large intestines ), the cecum, appendix, descending colon, transverse colon, ascending colon, anus, and rectum. The appendix is considered non-necessary for healthy, normal bowel function in the digestive process. The large intestine is roughly 5-6 feet in length, and is called the large intestine because of it’s width.
* The small intestine which includes the jejunum, ileum, and duodenum. Let the name come as no accurate description, the small intestine is around 20 feet long, and consumes the vastness of the abdominal cavity.
To view a detailed image of the bowel, please visit www.instantanatomy.com. There, the actual size, shape, structure, and other areas of interest pertaining to the bowel’s anatomy may be viewed at leisure.
Function of the Bowels
The purpose of bowel function is to absorb water, minerals, nutrients, and vitamins for the healthy functioning of the body. Gastric juices, called bile, are present in the stomach and break down food and liquids so they may proceed to the bowels. Once the processed matter reaches it’s destination at the beginning of the large intestine, called the cecum, it is squeezed by frequent contractions and mixed with digestive fluids. The cecum actually connects the large and small intestines, and is basically a small pocket formation.
Once the process is underway, small, digit-like protrusions, called the villi, “ sweep” the digestive matter through the remainder of the bowels. This function is addressed as peristalsis. Many types of bacteria are hard at work in the bowels and are labeled “ flora”. “ Flora” are natural, healthy bacteria, such as yeast, that aide the digestive process. While all individuals have bacteria present in their digestive tract, no two individuals will possess the exact same bacteria.
Digestive matter is then entered into the colon for further processing. While in the colon, extra water and salts are extracted and absorbed for the body’s usage. The well digested matter is then pushed along to the rectum. Involuntary spasms of the rectum, which triggers the need to have a bowel movement, will cause the material to be deposited at the anus for expulsion. The bile that has broken down the fats during digestion is sent to the liver for further processing, and then is recycled for further digestive use.
* Neonates do not have the presence of bacteria in their digestive tracts until the moment of birth.
* When the body feels pain, particularly moderate to severe, the bowels will slow down their functions, and bowel sounds will become less audible.