1. By Jacob G., Sophie B., Jaeden P., and Katherine G.

2. The digestive system exists for the intake and break-down of food to make energy for the body in the form of ATP. Food travels from the mouth, down the esophagus, and into the stomach, where digestion occurs. Remaining food waste then passes through the intestines to be further broken down and is then excreted through the anus (liquid waste through the urethra).

3. ●An average adult human mouth has 32 teeth built for various functions ○Incisors cut ○Molars chew ●Saliva begins breaking down food. Although humans always have saliva in their mouths, more is excreted through skin pores when food enters the mouth ●Tongue moves food around and pushes it to the back of the throat, where it is then swallowed

4. ●The throat divides into two passages: The trachea and the esophagus ●Trachea used for breathing (passage to the lungs) ○If food stops in the throat or trachea, it can cause the person to choke ●The esophagus gives food a path to travel to the stomach ●Powerful esophageal muscles force food to travel down, even against gravity (you can still eat upside down)

5. ●The process of digestion in the stomach (and intestines) extracts all useful nutrients and vitamins from food and drink through the utilization of gut bacteria, stomach acid, and enzymes ●Stomach is filled with highly acidic stomach acid (1.5-3.5pH; can dissolve some metals) to break down food

6. ●Also called the small bowel ●Takes care of most of digestion ●Actually longer than the large intestine (about 20 feet long), but only as wide as a person’s middle finger ●The duodenum breaks down food while the jejunum and the ileum absorb nutrients and transport them to the bloodstream

7. ●Intestinal failure occurs when a person’s intestines cannot adequately digest food and absorb vital nutrients (fluids, electrolytes, etc) ●People suffering intestinal failure may be born with the condition or develop it later in life ●Most common cause is short bowel syndrome, when half or more of the small intestine has been removed ●Can also be caused by Crohn’s Disease, chronic idiopathic intestinal pseudo- obstruction syndrome, or an underlying digestive disorder

8. ●Patients are treated with total parenteral nutrition (TPN) ●Most of the patient’s calories and nutrients are injected through a catheter ●An intestinal transplant may be required if complications become life- threatening

9. ●Also known as the colon or large bowel ●The last step of the digestion process ●Absorbs remaining water from food that cannot be digested by the small intestine and leaves behind waste (feces) ●

10. ●Villi are small, finger-like projections about 1 mm long on the inside of the small intestine ●They are built to increase surface area in the small intestine for maximum nutrient absorption

12. ●Celiac Disease is the immune reaction that some have when they ingest gluten, which is found in many grains such as wheat, rye, and barley. ●When a sufferer of Celiac eats gluten, their immune system responds by damaging or destroying the villi within the small intestine

13. ●Without villi, foods fail to be digested fully and sufferers may ●Cannot be cured, but its symptoms are preventable (just refrain from eating gluten) ●The current gluten-free fad has helped by introducing various gluten-free foods

14. ●The liver secretes bile to aid in digestion ●It also metabolizes toxins such as alcohol and drugs that are taken orally ●Glucose is stored by the liver in the form of glycogen to be released into the bloodstream as glucose later on; this helps the body maintain homeostasis.

15. ●The pancreas produces enzymes to aid the small intestine in digestion ●Enzymes are released into the duodenum, a section of the small intestine

16. ●The gallbladder is a small sac filled with bile that rests below the liver ●Used for storage after the liver secretes bile and before bile is released into the intestine

17. ●Sugars are stored by the liver in the form of glycogen to be later released into the bloodstream as glucose ● The pancreas secretes a hormone called glucagon to promote the breakdown of glycogen in the liver

18. ●The digestive system maintains homeostasis by maintaining stomach acid pH-a thick mucous lining surrounds the stomach so that the stomach does not digest itself or other bodily tissues ●Bile salts, enzymes and bicarbonate in the small intestine, along with villi, return water to the body and filter out nutrients and vitamins ●The liver helps maintain blood sugar level by slowly adding glucose from food to the blood stream