BIO 004 · Human Anatomy
The Accessory Digestive Organs
Block 4 · Module 3: Accessory Organs of Digestion
A reference for the accessory digestive organs video and lab. This page covers the teeth and tongue, the salivary glands, the liver, the gallbladder and the path of bile, and the pancreas. The focus is on the structures and the job each one does.
How to use this sheet Toggle the toolbar above. Notes prints the full reference for review. Study prints as a fill-in-the-blank worksheet. Print it, then write each definition while you watch the video or read your book. Quiz me is on-screen typing practice: type the term, click Reveal to check yourself. The comparison grids respond to Study and Quiz too, with a Reveal button on each row.
The Foundations video gives you a complete foundational understanding of this topic, enough on its own for a foundational course. Learn it first, then move on to the Deep dive, which adds the majors-level depth for this course.
- Name the six accessory digestive organs and the role of each.
- Identify the structures of the liver, gallbladder, and pancreas.
- Trace the path of bile from the liver to the small intestine.
Your pre-work
Work through these the evening before class. None of it is turned in. It is how you learn the material and build your spaced recall.
This is more than a checklist. Ticking these boxes is the start, not the finish. Committing this material to memory and being able to apply it takes considerable time and repeated effort. You are not done when the boxes are checked. Put in the real hours, and keep coming back for frequent recall and review until the material is genuinely yours.
The accessory organs
Add a labeled view of the salivary glands, liver, gallbladder, and pancreas in place.
The liver and gallbladder
Add a labeled view of the liver lobes, the gallbladder, and the bile ducts.
The path of bile
Add a labeled diagram of the duct system from the liver to the duodenum.
The Accessory Organs, an Overview
The accessory digestive organs are not part of the food tube itself. The teeth and tongue work on food in the mouth; the rest add secretions to the canal through ducts.
- Accessory digestive organsthe teeth, tongue, salivary glands, liver, gallbladder, and pancreas
- Teeth and tonguethe accessory organs that make direct contact with food in the mouth
- Glandular accessory organsthe salivary glands, liver, and pancreas, which produce secretions delivered through ducts
- Storage organthe gallbladder, which stores and concentrates bile until it is needed
The Teeth and Tongue
The teeth and the tongue prepare food in the mouth, breaking it down and moving it for chewing and swallowing.
- Teeththe accessory organs that cut and grind food during chewing
- Tonguea digestive organ of skeletal muscle covered with mucous membrane; it forms the floor of the mouth
- Extrinsic tongue musclesmuscles that originate outside the tongue and move it side to side and in and out
- Intrinsic tongue musclesmuscles within the tongue that alter its shape and size for speech and swallowing
- Lingual frenulumthe midline fold of mucous membrane anchoring the tongue to the floor of the mouth
- Papillaethe projections on the tongue surface that carry taste buds and aid the grip on food
- Lingual glandssmall glands in the tongue that secrete mucus and watery fluid
The Salivary Glands
Saliva keeps the mouth moist, cleanses it, and begins the breakdown of food. Three large pairs of glands produce most of it. Compare them.
| Gland | Location |
|---|---|
| Parotid glands | anterior and inferior to the ears, between the skin and the masseter muscle; the duct opens by the second upper molar |
| Submandibular glands | in the floor of the mouth, along the inner side of the mandible; the ducts open near the lingual frenulum |
| Sublingual glands | beneath the tongue, above the submandibular glands; the ducts open onto the floor of the mouth |
- Minor salivary glandssmall labial, buccal, palatal, and lingual glands scattered through the lining of the mouth
- Salivathe watery secretion that moistens, cleanses, and lubricates food and begins its breakdown
The Liver
The liver is the largest gland in the body. It sits below the diaphragm, mostly in the upper right abdomen, and it makes bile.
- Liverthe large gland below the diaphragm; it produces bile
- Right and left lobesthe two principal lobes of the liver, separated by the falciform ligament
- Quadrate and caudate lobestwo smaller lobes on the posterior and inferior surface
- Falciform ligamentthe fold of peritoneum that suspends the liver from the anterior abdominal wall and diaphragm
- Ligamentum teresthe round ligament; a fibrous cord in the free edge of the falciform ligament, a remnant of the fetal umbilical vein
- Hepatocytesthe functional cells of the liver, arranged in plates called hepatic laminae
- Hepatic sinusoidsthe wide, leaky capillaries that run between the plates of hepatocytes
- Bile canaliculithe tiny channels between hepatocytes that collect the bile they make
- Portal triadthe trio found at the corner of each liver lobule: a bile duct, a branch of the hepatic artery, and a branch of the hepatic portal vein
The Gallbladder and the Path of Bile
The gallbladder is a small sac on the underside of the liver that stores bile. Bile travels a branching set of ducts to reach the small intestine.
- Gallbladderthe pear-shaped sac on the posterior surface of the liver that stores and concentrates bile
- Fundus, body, and neckthe three regions of the gallbladder, from the broad inferior end to the tapered superior end
- Cystic ductthe duct that carries bile to and from the gallbladder
- Common bile ductthe duct formed where the common hepatic duct and the cystic duct join
- Hepatopancreatic ampullathe ampulla of Vater, the short widened duct where the bile duct and pancreatic duct meet before the duodenum
Bile drains away from the liver cells along a path of widening ducts to reach the duodenum.
- Bile canaliculitiny channels between hepatocytes collect the bile
- Hepatic ductsthe bile is gathered into the right and left hepatic ducts, which merge into the common hepatic duct
- Cystic duct and gallbladderbile may detour into the gallbladder for storage through the cystic duct
- Common bile ductthe common hepatic and cystic ducts join to form the common bile duct
- Hepatopancreatic ampullathe common bile duct joins the pancreatic duct at the ampulla
- Duodenumbile enters the small intestine at the major duodenal papilla, past the sphincter of Oddi
The Pancreas
The pancreas lies behind the stomach. It is both an exocrine gland, secreting into the duodenum, and an endocrine gland.
- Pancreasthe gland posterior to the stomach, retroperitoneal in position
- Head, body, and tailthe three regions of the pancreas, from the wide end in the curve of the duodenum to the tapered end
- Pancreatic ductthe main duct, also called the duct of Wirsung; it joins the common bile duct
- Accessory ductthe smaller duct, also called the duct of Santorini, that empties separately into the duodenum
- Major duodenal papillathe raised opening in the duodenal lining where the hepatopancreatic ampulla delivers bile and pancreatic juice
- Sphincter of Oddithe muscular ring that controls flow through the hepatopancreatic ampulla into the duodenum
- Acinithe exocrine clusters of the pancreas that produce pancreatic juice; about 99 percent of the gland
- Pancreatic isletsthe endocrine clusters of the pancreas that produce hormones; about 1 percent of the gland
Common Disorders of the Accessory Organs
Compare the common disorders of the accessory organs by the structure each one affects.
| Disorder | What it is |
|---|---|
| Gallstones | hardened deposits that form in the gallbladder and can block the bile ducts |
| Cholecystitis | inflammation of the gallbladder, often caused by a blocking gallstone |
| Hepatitis | inflammation of the liver, commonly from a viral infection |
| Cirrhosis | the replacement of healthy liver tissue with scar tissue, with loss of liver function |
| Jaundice | a yellowing of the skin and eyes from a buildup of bilirubin, often from liver or bile duct disease |
| Pancreatitis | inflammation of the pancreas |
| Mumps | a viral infection that inflames and enlarges the parotid glands |
See also: The Alimentary Canal for the digestive tube these organs empty into, and The Urinary System, the next page in this block.
Study questions
Work on answering these in writing, in your own words. They are the questions to bring to class, and good practice for the reasoning the exams ask for.
- Trace the path of bile from where it is made to where it enters the duodenum, naming each duct it passes through.
- The pancreas has both an exocrine and an endocrine role. Name the structure responsible for each and where its product goes.
- Why does the liver receive blood from two different sources? Name them and state what each one delivers.
- After a gallbladder is removed, bile still reaches the intestine. Explain how, using the duct anatomy.
Step 2 . Retrieval check
Now explain it back, in your own words.
In 60 words or more, pull together what the video just taught you. Include the key concepts. This is the point where the learning actually sticks. After you submit, your spaced-recall cards for this topic unlock.