Digestive Anatomy study-question guide

1. Two organ groups and the six processes

1. Name the two groups of organs in the digestive system, and list the organs of the GI tract (alimentary canal) in order from the mouth to the anus. Recall
2. Give the length of the GI tract in a living person versus after death, and explain what accounts for the difference. Apply
3. List the six basic processes of the GI tract, and sort each as either mechanical or chemical where that applies. Recall
4. Which substances in food can be absorbed without chemical digestion? Reason from what "digestion" is meant to accomplish. Reason

2. The four layers of the GI wall

1. Name the four basic layers of the GI tract wall in order from deep to superficial, over the span from the lower esophagus to the anal canal. Recall
2. Which outermost layer is called serosa and which is called adventitia, and what determines which name a given segment gets? Apply
3. What tissue makes up the submucosa, and what does this layer carry? Recall

3. The mucosa and its three sublayers

1. Name the three layers of the mucosa from the lumen outward, and give the tissue of each. Recall
2. Which mucosal layer is in direct contact with the contents of the GI tract, and which is the thin plate of connective tissue beneath it? Apply
3. What is the muscularis mucosae made of, and how does it differ from the muscularis (externa) deeper in the wall? Reason

4. Muscularis and the enteric nervous system

1. Where in the GI tract is the muscularis skeletal muscle, and where is it smooth muscle? Give the function tied to each. Recall
2. The enteric nervous system is called the "brain of the gut." Name its two plexuses, give the location of each, and state what each controls. Apply
3. The myenteric plexus sits between which two muscle layers, and why is that the logical place for a plexus that controls motility? Reason
4. Contrast the sensory receptors of the ENS: what do chemoreceptors respond to versus mechanoreceptors? Recall

5. Extrinsic (autonomic) innervation

1. Which cranial nerve carries parasympathetic supply to most of the GI tract, and which region is the exception (and what supplies it instead)? Recall
2. State the general effect of parasympathetic stimulation on GI secretion and motility, and the general effect of sympathetic stimulation. Apply
3. Emotions such as anger, fear, or anxiety can slow digestion. Reason through which division is being activated and how that reaches the ENS. Reason

6. Peritoneum and the peritoneal cavity

1. The peritoneum is the largest serous membrane in the body. Name its two serous layers by tissue type (top and bottom). Recall
2. Distinguish parietal peritoneum, visceral peritoneum, the peritoneal cavity, and peritoneal fluid. Apply
3. What is ascites, and how does it relate to the peritoneal cavity? Reason

7. The five peritoneal folds

1. Name the five peritoneal folds. Recall
2. The falciform ligament attaches which organ to what, and why is that organ unique in this respect? Apply
3. The lesser omentum carries three important structures to the liver. Name them. Recall
4. Contrast the mesentery and the mesocolon: which parts of the intestine does each bind to the posterior abdominal wall? Apply
5. Which fold is the largest, is full of fat, and contributes to a large abdomen in obesity? Reason

8. Retroperitoneal organs

1. Define a retroperitoneal organ. Recall
2. List the retroperitoneal organs given in the lecture. Recall
3. Given that the pancreas and the duodenum are retroperitoneal, predict which surface of each is covered by peritoneum. Reason

9. Mouth, palate, and tonsils

1. What tissue lines the internal surface of the cheeks and lips, and what muscle lies between the layers of the cheek? Recall
2. Contrast the hard palate and soft palate: location, what forms each, and the function of each. Apply
3. What is the labial frenulum, and what is the function of the lips in eating and speech? Recall
4. Name the palatine and lingual tonsils by location. Recall

10. Salivary glands and saliva

1. Name the three pairs of salivary glands, and give the location of the parotid and the submandibular glands. Recall
2. List the functions of saliva, and give the approximate water-to-solute composition. Apply
3. Which enzyme in saliva begins chemical digestion, and what does it act on? Recall
4. Mumps is a clinical correlation for which salivary gland? Reason from that gland's location. Reason

11. Tongue, pharynx, and esophagus

1. What tissue is the tongue built from, and what does the tongue plus its associated muscles form? Recall
2. Describe the pharynx: its shape, what it extends between, and its tissue composition. Apply
3. Trace the esophagus from its origin to its termination, and name the esophageal hiatus and the vertebral level where it pierces the diaphragm. Apply
4. The superior and middle parts of the esophagus contain skeletal muscle. Reason why that fits the idea of voluntary versus involuntary swallowing. Reason

12. Stomach: regions and histology

1. Name the four regions of the stomach, and the three subdivisions of the pyloric part in order toward the duodenum. Recall
2. The stomach muscularis has three layers of smooth muscle instead of the usual two. Name all three, and say which one is limited to the body of the stomach. Apply
3. Define gastric pits and gastric glands, and give the epithelium at the surface of the gastric mucosa. Recall
4. At the lesser and greater curvatures the visceral peritoneum continues as which two structures? Reason

13. Pancreas

1. Give the location of the pancreas and name its three parts, noting which part sits in the "C" of the duodenum. Recall
2. Name the two ducts that connect the pancreas to the duodenum. Recall
3. Distinguish the exocrine role of the pancreas from where its secretions ultimately go, and why that fits chemical digestion happening in the small intestine. Reason

14. Liver: anatomy and histology

1. Give the location of the liver and name its four lobes. Recall
2. What passes through the porta hepatis? Name the vessels and duct, and state what the round ligament and falciform ligament are. Apply
3. Define hepatocytes and hepatic laminae, and describe the hepatic sinusoids that border the plates. Apply
4. What are bile canaliculi, and where does the bile they collect travel next? Recall
5. In the fetus the liver has a role it loses after birth. Name it and reason why the fetus needs it. Reason

15. Gallbladder and the biliary route

1. Give the location and shape of the gallbladder, and name its parts (fundus, body, infundibulum, neck). Recall
2. What is the function of the gallbladder, and what does the sphincter of Oddi do? Apply
3. Trace bile from the hepatocytes that make it to the duodenum, naming the storage step along the way. Reason

16. Small intestine

1. Name the three regions of the small intestine in order, note which is retroperitoneal and C-shaped, and name the sphincter at each end of the whole small intestine. Recall
2. In the mucosal epithelium, contrast absorptive cells and goblet cells, and name the intestinal glands (crypts of Lieberkuhn). Apply
3. Name the Paneth cells and enteroendocrine cells found in the crypts, and give what the S cells and CCK cells secrete. Recall
4. Describe the two muscle layers of the small intestine muscularis, and explain why most of the small intestine has a serosa while part of the duodenum does not. Reason

17. Large intestine

1. List the functions of the large intestine, including what its bacteria produce. Recall
2. Give the dimensions of the large intestine and how it is attached to the posterior wall. Apply
3. The large intestine has no circular folds or villi. Reason how its histology differs from the small intestine and what that predicts about its level of absorption. Reason

Stuck on one? Open the lecture slides, find the slide, and trace it, then come back and answer from memory.