This chapter should help the student to:

• List the accessory glands attached to the digestive tract by their ducts and describe their roles in digestion.
  
• Compare mucous and serous secretory cells in terms of their structure, staining, and secretions.
  
• Distinguish between the major salivary glands based on the content and distribution of serous and mucous cells.
  
• Relate pancreatic acinar cell ultrastructure to its function.
  
• Describe the liver’s double blood supply.
  
• Relate the hepatocyte’s complex ultrastructure to its many functions.
  
• Describe the boundaries and contents of the classic liver lobule, the portal lobule, and the hepatic acinus. Understand the functions that gave rise to these overlapping views of liver organization.
  
• Describe the structure, function, and location of the gallbladder.
  
• Identify the gallbladder in a micrograph and distinguish it from the small intestine.
  
• Identify and distinguish among digestive glands in micrographs; distinguish between adenomeres and ducts; and identify the different types of associated ducts, cells, and other substructures.

1. Compare serous cells with mucous cells in terms of their secretory product, staining properties, and the type of alveoli they typically comprise (acinar or tubular) (II.B.1).

2. Name the three types of paired salivary glands (II.C–E) and compare them in terms of:

1. 
   

   Contribution to salivary volume

   
   
2. 
   

   Proportion of serous and mucous cells found in each gland

   
   
3. 
   

   Presence of serous demilunes

   
   
4. 
   

   Composition of their secretions

   
   
5. 
   

   Presence of striated ducts (I.F.1.b)

3. Describe the structure and function of striated ducts (I.F.1.b).

4. Compare the saliva produced in response to sympathetic versus parasympathetic stimulation (II.G).

5. Name the endocrine component of the pancreas (III.A).

6. Sketch a cross-section of a pancreatic acinus (Fig. 16–1) and label the following:

1. 
   

   Acinar cells

   
   
2. 
   

   Nuclei

   
   
3. 
   

   RER

   
   
4. 
   

   Golgi complex

   
   
5. 
   

   Zymogen granules

   
   
6. 
   

   Basal lamina

   
   
7. 
   

   Lumen

   
   
8. 
   

   Centroacinar cell

   
   
9. 
   

   Intercalated duct

7. Describe two types of pancreatic exocrine secretion (III.B.1 and 2) in terms of their composition and role in digestion, the cells primarily responsible for their secretion, and the enteroendocrine hormone that stimulates their release.

8. Into which digestive tract segment are pancreatic exocrine secretions delivered (III.A)?

9. Compare the exocrine pancreas with the parotid gland in terms of the chief secretory cell type (serous or mucous) (I.D), presence of centroacinar cells (III.B.2), islets of Langerhans (III.A), and striated intralobular ducts (I.F.1.b).

10. Name the two vessels that provide the liver’s blood supply (IV.A, C.1 and 2) and compare the blood they carry in terms of its origin (the vessels giving rise to those entering the liver), its contribution (%) to liver blood volume, and its oxygen, nutrient, and bilirubin content.

11. In which vessels in the liver does the dual blood supply first become mixed (IV.C.3)?

12. Sketch a cross-section of three adjacent classic liver lobules and include and label the following (Figs. 16–2 and 16–3):

1. 
   

   Portal triads

   
   
2. 
   

   Branches of the hepatic artery

   
   
3. 
   

   Branches of the hepatic portal vein

   
   
4. 
   

   Bile ducts

   
   
5. 
   

   Central veins

   
   
6. 
   

   Hepatic sinusoids

   
   
7. 
   

   Space(s) of Disse

   
   
8. 
   

   Hepatocytes

   
   
9. 
   

   Endothelial cells

   
   
10. 
    

    Kupffer cells

    
    
11. 
    

    A portal lobule (outline)

    
    
12. 
    

    A hepatic acinus (outline)

    
    
13. 
    

    The direction of (use arrows):

    
    
    
    
    1. 
       

       Blood flow

       
       
    2. 
       

       Bile flow

       
       
    3. 
       

       Lymph flow

    
    

13. Name the three principal components of a portal triad (IV.E.1.a). Which has the largest lumen?

14. Name the two major cell types that border the hepatic sinusoids (IV.C.3).

15. Name the three major cell types that border the space of Disse (IV.C.3).

16. Name the cells that border the bile canaliculi (IV.D.1.a).

17. Name several proteins synthesized and secreted by hepatocytes (IV.D.1.b). Are these endocrine or exocrine products?

18. Name the hepatocyte organelles or inclusions involved in the following functions:

1. 
   

   Protein synthesis and secretion (2.III.C.1.a and b)

   
   
2. 
   

   Drug detoxification and inactivation (IV.D.1.b)

   
   
3. 
   

   Synthesis of bilirubin glucuronide (IV.F.1.b)

   
   
4. 
   

   Synthesis of bile acids (IV.F.1.a)

   
   
5. 
   

   Storage of lipid (IV.D.3; 2.III.H)

   
   
6. 
   

   Storage of glycogen (IV.D.1.b; 2.III.H)

19. Name the liver’s exocrine secretory product; describe its composition and function (IV.D.1.b and F.1).

20. List, in order, the named structures through which bile flows after secretion by the hepatocytes and name the segment of the digestive tract into which it is delivered (IV.F.2).

21. How is the flow of bile into the digestive tract regulated (IV.F.2)?

22. List the functions of the gallbladder (V).

23. Compare the walls of the gallbladder with those of the small intestine in terms of the lining epithelium, mucosal branching, submucosa, and fiber orientation in the muscularis (V.A–C).

24. Describe the process by which bile fills the gallbladder (IV.F.2).

25. Name the enteroendocrine hormone that stimulates the contraction of smooth muscle in the gallbladder wall, thereby ejecting bile into the duct system (V).

I. General Features of the Glands Associated with the Digestive Tract

A. Components of the System