The Digestive System Part 1 Anatomy of… Chapter 14 Photo Credit: science.nationalgeographic.com

The Big Picture Our digestive system Takes in food Breaks it down with mechanical and physical processes into nutrients It then absorbs these nutrients into the blood stream Then rids the body of the unused remains

The Alimentary Canal The alimentary canal is the “tube” that our food and ultimately our food waste travel through. These notes, part 1, look at the organs that form the canal. Part 2 looks at the organs that help in the process of digestion; the accessory organs. In the above figure, all the labeled parts but the liver form the alimentary canal

Organs of the Alimentary Canal When you put something in your mouth, and if it later pops out your anus, it traveled through your body but it was never inside your body Here’s the list of organs that “something” would come in contact with Mouth Pharynx Esophagus Stomach Small intestine Large intestine Anus Putting food in your body is like putting your finger through a donut; it passes through the donut but never enters the donut!

Mouth The mouth is also called the oral cavity The players here are the lips, cheeks, hard palate (anterior roof of mouth), soft palate (posterior roof of mouth), uvula (dangles from the soft palate), tongue, and teeth

Uvula The uvula seems to function in aiding speech, swallowing, prevent food from entering nasal cavity, and in the “gag” reflex

Pharynx As food is leaving the mouth it passes into the pharynx The pharynx is the common area that both food and air pass through

Esophagus A 10” long tube from mouth to stomach Below is a an endoscope view looking into this tube

Stomach A sac with two valves at both ends. The cardioesophageal sphincter at the top and the pyloric spincter valve at the bottom It can hold up to 4 L or a gallon of food and is used in both digestion and temporary storage

Small Intestine It’s big; the major player in digestion, and the longest part at up to 13’ long in a live person. Has three major parts Duodenum Jejunum ileum

The small intestine is lined with intestinal villi - increase surface area to absorb nutrients, connect to vessels

Large Intestine Short (5’) but bigger diameter than the small intestines It absorbs water and dries out the waste It’s divided into parts: Ascending colon Transverse colon Descending colon Sigmoid colon The sigmoid colon leads to your anus and the end of the tube…

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