Draw the head as a profile rather than straight on to make it easier to show the digestive organs in the head. If you wish, feel free to be creative and embellish this outline a bit. You can draw eyes and a nose and ears and hair. You could even give your person a name if you feel like it! Just don’t draw over the torso or you will obscure your model.
Digestion begins in the mouth with ingestion. Salivary glands release saliva containing digestive enzymes to begin breaking down food while you chew. The tongue helps the food to move back in your throat creating a bolus while the teeth break it down in a process known as mastication.
The food moves from the mouth into the esophagus, which carries it down into the stomach. The esophagus is made of smooth muscle that relaxes and contracts to move your food down with a wavelike motion, called peristalsis. If you wish to make your model more advanced, you can include the pharynx. The pharynx is located behind the mouth and moves food into the esophagus. You can feel it when you swallow. In your model, you can simply draw a small diagonal line towards the top of your esophagus and the part above the line can be the pharynx and the part below can be the esophagus. [3] X Research source It you wish to make your model more advanced, you can also include the epiglottis. The epiglottis is a small flap just below the pharynx that directs food into the esophagus. If you drew a pharynx, the diagonal line can be the epiglottis.
The stomach helps churn and digest food using gastric juices containing hydrochloric acid and pepsin to help break it down. The food remains in the stomach for about 3-4 hours. At this point it is no longer food, but has an oatmeal-like consistency and is called “chyme. "
The liver produces bile to help break down fats. While the food doesn’t enter the liver, it processes the nutrients that are absorbed from the small intestine.
The gallbladder stores the bile produced in the liver. It then mixes the bile with the food that passes by, breaking down fats.
The pancreas releases digestive juices that aid in breaking down carbohydrates, protein, and fat as the food leaves the stomach. It also regulates blood sugar. [8] X Research source
Add a diagonal line to indicate the muscular valve, called the pyloric sphincter, between the duodenum of the small intestine and the stomach. The small intestine is about 18–22 feet (5–7 m) long! This is where the majority of digestion takes place. The small intestine contracts to move food through it with the help of bile secretions and pancreatic and intestinal juices, allowing it to absorb nutrients with villi. To make a more advanced model, you can distinguish the different parts of the small intestine. The duodenum is a small tube connecting the stomach to the jejunum. The jejunum is where the majority of digestion takes place and is the middle part of the small intestine. The ileum is the last region of the small intestine that connects to the large intestine. [9] X Research source
The appendix is a small pouch-like structure that is thought to have lost its purpose and become more of a liability than an aid in digestion. But it is part of the digestive system and sits where the small and large intestines connect.
The passage of food is slower through the large intestine in order to allow for fermentation by bacteria and other microorganisms, called gut flora. The large intestine processes whatever cannot be used in digestion. It absorbs whatever it can, especially water, but then the rest will expelled as waste after about 12 hours. To make a more advanced model, distinguish between the different parts of the large intestine. The cecum is attached to the appendix and connects it to the ascending colon. The ascending colon goes straight upwards and connects to the transverse colon, which goes across the body. The transverse colon connects to the descending colon, which carries food down into the sigmoid colon, which goes directly to the rectum. [10] X Research source
The rectum stores feces until expulsion. The anus then expels waste.
For overlapping organs, try using using lighter and darker shades of the same color. The areas where they overlap will be darker, and the areas where it is a single organ will be lighter.
If you prefer not to write the names of the organs on your model, you could instead make a key at the bottom or on another piece of paper where you draw a little square of each color and write the name of the organ next to it. This will allow you to quiz yourself on the names of the organs because they won’t be written right next to them. If you wish to make your model more advanced, you can differentiate the parts of the small intestine. Simply draw a small line towards the beginning of the small intestine to show where the duodenum turns into the jejunum and then draw a small line towards the end of the small intestine to show where the jejunum becomes the ileum. If you wish to make your model more advanced, you can also differentiate the parts of the large intestine. Simply draw a small line to divide each part. The cecum is attached to the appendix and connects it to the ascending colon. The ascending colon is the part that goes straight upwards. It connects to the transverse colon which goes across the body and is the largest part of the large intestine. The transverse colon connects to the descending colon, which carries food downward. Finally, there is the sigmoid colon which goes directly to the rectum.
