Diapers and wipes. Yes, one of the more expensive parts in the beginning of a child’s life. Let us explore why exactly we need to use all these diapers and wipes. In other words, why do we have to go to the bathroom?
Why do we go to the bathroom? In simple terms, our body needs to get rid of all unwanted substances which enter our body. But let us take a closer look at what actually is happening.
What is the digestive system? The digestive system is an absolutely incredible organ system which takes in food, breaks it down into its nutrient molecules, absorbs these molecules into the bloodstream, and rids the body of indigestible remains (Marieb, Elaine N. and Hoehn, Katja, Human Anatomy and Physiology, 8th ed., San Francisco, Pearson Education Inc., 2010. Print). What people may not know is that digestion actually begins the moment you put food into your mouth. The digestive system begins with the mouth, and ends at the anus, a pathway which can be shown with the following diagram:
The above diagram also gives some of the functions of each part of the digestive system. It is truly complex and amazing to ponder this incredible system. Entire books have been written just on this one system. Every single part is exact and precise in what it does. Just to give some examples of what this system does: As soon as food is put into the mouth, it encounters saliva. Saliva is not merely water. It is 97 to 99.5% water. But it’s the other stuff which does most of the action. The solutes (things dissolved in the water) of saliva include electrolytes such as sodium and potassium; digestive enzymes salivary amylase and lingual lipase; the proteins mucin, lysozyme, and IgA (immunoglobulin A, part of the immune system); and metabolic wastes, such as urea and uric acid (Marieb, Elaine N. and Hoehn, Katja, Human Anatomy and Physiology, 8th ed., San Francisco, Pearson Education Inc., 2010. Print). The salivary enzymes begin the breakdown of sugars even before the food has entered the esophagus.
As the food progresses through the esophagus, stomach, small intestine, and large intestine, different types of digestion occur. (Just as an aside, the above diagram should help you understand that when a child says their stomach hurts and they have to use the bathroom, it is probably not their stomach; it is most likely their intestines which want to rid themselves of their contents.)
Relatively recent research has shown that there are trillions (about 100 trillion) of bacteria living in our large intestines. These bacteria are called gut flora. These bacteria are crucial to our digestion and excretion of substances. Some of the functions of these bacteria are to metabolize some host-derived molecules (mucin, heparin, and hyaluronic acid) and to ferment some of the indigestible carbohydrates (xylan, cellulose, and others). This releases irritating acids and a mixture of gases, such as dimethyl sulfide, hydrogen gas, nitrogen gas, methane, and carbon dioxide. Some of these gases, such as dimethyl sulfide, are quite smelly. Around 500mL of gas is produced each day, increased by consumption of carbohydrate-rich foods like beans. Gut flora also synthesize B vitamins and most of the vitamin K that the liver needs to synthesize some clotting proteins (Vitamin K is crucial to the ability for the blood to clot. This is why Vitamin K shots are given to newborns.). Most of the bacteria exist peacefully with our guts (Marieb, Elaine N. and Hoehn, Katja, Human Anatomy and Physiology, 8th ed., San Francisco, Pearson Education Inc., 2010. Print).
What gives feces its color? This is actually more complex than it sounds because the color of feces (as well as urine) is actually intertwined with the circulatory system. To make a long story short (see diagram at the end of this paragraph for a more complicated pathway), the heme molecule of hemoglobin (which is the molecule in red blood cells which carries oxygen) is sliced into its iron core, which is stored for reuse, and the rest is degraded into bilirubin, which has a yellow pigment. Bilirubin is picked up by the liver, which hands it over to the small intestine, where it is metabolized to become urobilinogen. Most of this leaves the body in feces, as a brown pigment called stercobilin (Marieb, Elaine N. and Hoehn, Katja, Human Anatomy and Physiology, 8th ed., San Francisco, Pearson Education Inc., 2010. Print). This is why feces has its color. The color will probably vary based on what was eaten, which is why nursing infants usually have a yellowish excrement.
(http://intranet.tdmu.edu.ua/data/kafedra/internal/normal_phiz/classes_stud/en/stomat/2 course/2 Cycle Physiology of blood/01 physiology of blood, leukocytes, blood types.files/image081.jpg)
Newborn babies usually double their birth weight by six months. Their caloric intake and food processing ability are incredible. A 6-week old infant weighing about 4kg drinks about 600mL of milk every day! However, the stomach of a newborn is very small, so feeding has to be frequent. Also, being that gastrointestinal peristalsis (peristalsis is basically the equivalent of putting food in a washing machine; the food is churned and broken down, and passed to the next part of the system) is inefficient, vomiting (or more commonly called “spit up”) occurs.
Infants cannot control when they go to the bathroom. A muscle called the external anal sphincter must be relaxed in order to allow feces to exit. This muscle is under voluntary control, so we can decide whether the muscle should be opened or closed. However, infants do not have control over their external anal sphincter, so defecation is involuntary. (Marieb, Elaine N. and Hoehn, Katja, Human Anatomy and Physiology, 8th ed., San Francisco, Pearson Education Inc., 2010. Print)