The Incredible Physiology Of The Colon
The colon includes the following parts: the colon, the colon, the rectum, and the anal canal. Together, they form the widest and shortest part of the digestive tract.
First, the proximal colon is responsible for the absorption of water and electrolytes. Next, the distal intestine stores all the feces until it leaves the body.
These functions do not require colonic movements to be as strong as the small intestine. In fact, these movements are slow and subtle.
The movements of the colon are thus very similar to the movements of the small intestine.
In this article, we’re looking at everything you need to know about this awesome body part.
Colon physiology
Intestinal movements
As in the case of the small intestine, the movements of the colon can be divided into mixed movements and pushing movements.
Miscellaneous movements
These are a combination of the round and longitudinal muscles of the colon. It pushes the unstimulated part of the colon outwards.
After a couple of minutes, the process repeats itself, progressing slightly and pushing the feces further into the colon. In this way, pushing all the feces remains in the intestinal walls, facilitating the absorption of hydroelectrolytes.
Pushing movements
Push movements depend on “mass movements”. These movements are a modified form of peristalsis, or contractions, that connects the movements of the colon.
They push the stool forward. Mass movements usually occur three times a day and last for about 30 minutes at a time.
Mass movements respond to bloating. At other times, they may act in response to irritation.
Irritation occurs, for example, in connection with a patient’s ulcerative colitis.
The role of the ileum
The ileum prevents the waste from flowing back when it reaches the colon.
In addition, the colon reflexes control the movements of the ileum, helping to prevent backward migration. When the walls of the colon bulge, it sends signals that increase contractions in the sphincter and prevents intestinal peristalsis.
What happens if these processes change?
Generally speaking:
- Excessive intestinal motility leads to decreased absorption of substances. It therefore results in diarrhea or soft stools.
- Lack of intestinal motility increases the absorption of substances. This results in hard stools that later cause constipation.
Stool reflex
The defecation reflex gets rid of the stool.
When feces travels to the rectum, it gives the walls a signal to bulge, sending afferent signals through the Auerbach’s plexus. In response to these signals, peristaltic waves travel from the colon to the rectum. Thus, they push the feces out of the anus.
The Auerbach plexus sends inhibitory signals that relax the internal anal sphincter. As the peristaltic waves travel to the anus, the stool continues to move forward.
Excretion of substances
A kind of mucus allows secretion.
Mucus secretion is formed by direct stimulation of mucus cells. This also causes a reaction when the pelvic nerves are stimulated.
Mucus secretion has three functions. It:
- Protects the walls of the digestive tract from possible scarring and fecal acids.
- Keeps stool together.
- Protects the digestive tract from bacteria.
Absorption of substances
The large intestine receives about 1,500 ml of melt daily. It absorbs essentially most of the water and electrolytes located in the proximal colon.
As a result, the excreted faeces contain only about 100 ml of water and about 1-5 mEq of sodium and chlorine ions.
How does the colon absorb substances?
It absorbs sodium through the active transport of sodium-hydrogen exchange. Due to the electrical slope, some of the chlorine ions passively move inside the cells. The rest of the chlorine ions are absorbed into the bicarbonate ions in exchange.
The junctions between the cells of the colon are much narrower than the junctions of other digestive tract. As a result, they prevent the retrograde distribution of ions and cause better absorption of sodium.
Aldosterone is a great aid in sodium absorption. The resulting concentration causes water to be absorbed through osmosis.
Isn’t it wonderful how the body works?
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