Chapter 24 Reading Questions Continued
The Digestive System

Part 3: The Accessory Organs of the Small Intestine
        A. Role of the pancreas
        B. Anatomy and functions of the liver

17. As food enters the small intestine, there are secretions from accessory organs,
the pancreas, liver, and gall bladder, that aid in digestion. You will study these now
beginning with the pancreas.
    A. Describe the anatomy of the pancreas.
        Your pancreas lies _________________________ to the greater curvature of the stomach.
        The pancreas is in the shape of a hammer, with the head nuzzled into the ________________
         and the tail pointed towards the _______________________.

    B. Running through the pancreas is a duct to receive all the exocrine secretions called the                 
         _________________________ or __________________________________.

18. Examine the functions of the pancreatic cells.
      The pancreas is unusual as it serves as an endocrine as well as an exocrine gland.

NaHCO3 __________________________________________________
pancreatic amylase ___________________________________________
trypsin ____________________________________________________
lipase _____________________________________________________

        B. The endocrine cells are called ___________________________,
             these secrete two hormones _________________________ and
            _________________________ which control glucose levels in the blood.

            glucagon
            ________________________________________________________          
            ________________________________________________________

              insulin
            ________________________________________________________
            ________________________________________________________

19. Identify the role of the two hormones that influence pancreatic exocrine secretions.
They are the same hormones that shut down the stomach activity as food enters the
duodenum and control pancreatic functions.

CCK
_____________________________________________________________
_____________________________________________________________

secretin
_____________________________________________________________
_____________________________________________________________
(This can play a role in ulcer formation.)
(Do not forget the vagus nerve.)

20. The next organ to study is one of the few organs that is worthwhile as a food
due to its high nutritive value. A few years ago, Jamie Fiske's father pleaded for a
new one. It is the largest organ in the body. Ladies and Gentlemen! This is your liver!

A. Describe the gross anatomy of the liver. The liver lies in the upper right quadrant
of the abdominal cavity. It is divided into two large lobes, the major portion being the
___________________________ and the smaller ____________________________.
Separating these lobes is parietal peritoneum called the __________________________.
This superior membrane attaches the liver to the _______________________________

B. Describe the histology of the liver. Despite the size of the liver, there is a simple subunit called a lobule that performs the many liver functions. The lobule consists of epithelial cells called _________________________, these are like spokes of a wheel that radiate around a blood vessel called the ________________________. Between the rows of cells are spaces called _______________________ which bathe the liver in blood. Also found in these spaces are phagocytes called ____________________________.

C. Describe the blood flow through the liver. Remember back in Chapter 20 your friend, blood drop Y. Well, Y was ejected from the left ventricle and has been waiting for you in the aorta. If you follow Y's route to the liver, you will watch Y pass down into the abdominal aorta, then through the celiac artery and into the hepatic artery. Blood drop Y enters the liver and passes to the sinusoids which bathe the liver with oxygenated blood. You have another friend, blood drop Z. Of course Z has been traveling through the intestines picking up digested nutrients, from the intestinal capillaries in the villi. Z travels toward the liver to meet Y. Yes! Z travels through the hepatic portal vein and meets Y in the liver sinusoids.
Explain the meaning of this mixing of arterial and venous blood in the liver lobule.
____________________________________________________________
____________________________________________________________
____________________________________________________________
____________________________________________________________

After Y and Z pass through the liver sinusoids, they are drained from the liver lobule
through the central vein. Central veins unite to form the hepatic vein. Finally Y and Z
and dumped into the inferior vena cava.

D. List the blood vessels in the order of the pathway of blood through the liver.

1. _____________________ and _______________________
2. __________________________________
3. __________________________________
4. __________________________________
5. inferior vena cava

21. The liver performs over one hundred functions. Summarize the important functions of the liver.
      Keep in mind that carbohydrate, lipid, and protein metabolism will be covered in Chapter 25.

1. ____________________________________________________________________
    ____________________________________________________________________
    ____________________________________________________________________

2. ____________________________________________________________________
    ____________________________________________________________________

3. ____________________________________________________________________
    ____________________________________________________________________
 
4. ____________________________________________________________________

5. ____________________________________________________________________

6. ____________________________________________________________________

7. ____________________________________________________________________

8. ____________________________________________________________________

9. ____________________________________________________________________

10. ___________________________________________________________________

22. Bile emulsifies the fat in the bananas and artichokes and "a quart a day keeps cholecystitis away."
Each day your hepatic cells form 1000 mls of bile. List below the chemicals that form bile and their functions.

(Also thrown out in bile are the byproducts of drugs that have been detoxified by the liver)

23. Bile is stored in the ___________________________________.
When chyme enters the duodenum, the gall bladder contracts and ejects bile into the ______________________. Describe the role of bile in the small intestine. ___________________________________

24. Draw the gall bladder and it's associated ducts. Label with the following:

right hepatic duct
left hepatic duct
gall bladder
common hepatic duct
cystic duct
common bile duct

25. When hepatic cells are replaced by scar tissue, the condition is called cirrhosis.
List the causes of cirrhosis.

1.______________________________________________
2.______________________________________________
3.______________________________________________
4.______________________________________________

26. Helen Housewife has a liver inflammation called hepatitis.

Hepatitis A is caused by __________________________________
Hepatitis B is caused by __________________________________
Hepatitis C is caused by __________________________________

Focus Question
Describe how the main functions of the liver are best served by the structure of a liver lobule.

Part 4: The Small and Large Intestines

27. . If you draw a circle with a 6 inch radius around your belly button,
you have included the area containing your small intestine. Compacted
within the circle is 21 feet of tubing.

The first twelve inches is designated as the ________________,
the next eight feet is the ____________________,
and the final twelve feet is the ______________________.

The small intestine has two doors guarding the entrance and exit of chyme.
The one that releases chyme from the stomach is called the ________________________________
while the other releases digested remains into the large intestine and is
called the ________________________________________.

28. Identify the structural modifications of the small intestine that facilitate absorption.
The final hydrolysis of food and all absorption of nutrients takes place in the small
intestine. You need a large surface area for these functions, and the intestines provide
this with three types of structures. Describe the anatomy of each of them.

1. microvilli _____________________________________________
    ____________________________________________________
2.villi __________________________________________________
   _____________________________________________________
3. lacteal _______________________________________________

29. Food is propelled through the small intestine by two types of movement,
      segmentation and peristalsis.
      Describe these two mechanical movements using only three words.

segmentation ___________________________________________
peristalsis _____________________________________________

30. The villi are lined with simple columnar cells that must be replaced every day.
This emphasizes their role in absorption as well as their role in secretion of digestive
enzymes. Within each villus is a blood capillary to absorb monosaccharides and
amino acids and a lymphatic lacteal to absorb digested lipids.

List the digestive enzymes secreted by the intestinal brush border into the duodenum along
with the substrates they hydrolyze.

Focus Question
Now it is time to put together an information map for an essay summarize the hydrolysis of all foods in the digestive tract..

Is a penumbra one of the four food groups?

31. Identify the regions of the large intestine. Lastly, you will study the large intestine, that glamorous 5 feet of puckered tubing that surrounds the small intestine. Below is a drawing of the large intestine, label it with the following items and then draw arrows to show the direction of flow.

sigmoid colon

ascending colon

hepatic flexure

appendix

descending colon

rectum

ileum

splenic flexure

cecum

transverse colon

31. Examine the histology of the large intestine.

A. Are there villi in the large intestine?__________
B. Does the mucosa of the large intestine secrete enzymes?__________
C. Columnar cells in this section absorb _______________________,
while goblet cells secrete _______________________________
D. The longitudinal muscle layer of the muscularis does not encase the tube,
rather is appears in three thick bands called the ________________________________________.
E. When these muscle contract, the pouches formed are
called ________________________.

32. Describe the functions of the large intestine. Your large intestine does not secrete enzymes, but does serve a mechanical and chemical role in the final preparation of foods before elimination.

A. Mechanical digestion: believe it or not, food in the stomach and the
hormone gastrin affect the movement of food through the large intestine.
Describe the role of the gastro-colic reflex.
______________________________________________________
______________________________________________________

B. A major function of the colon is to absorb water from chyme. At the
cecum, the contents of the colon are liquid. By the time chyme reaches
the sigmoid colon, water is lost and the stool is firm. Explain why drinking
eight glasses of water a day is necessary. ______________________________________________________
______________________________________________________

C.  Chemical digestion: if the large intestine does not contain enzymes,
how does the final breakdown of food occur? Describe three roles of
the colon bacilli, Eschericia coli.

1._______________________________________________________
2._______________________________________________________
3._______________________________________________________

33. Colorectal cancer is one of the leading causes of death in the United States.
List two factors that contribute to this disease.

1._______________________________________________________
2._______________________________________________________

Identify four symptoms of colorectal cancer.

1._______________________________________________________
2._______________________________________________________
3._______________________________________________________
4._______________________________________________________

34. Dorito Della has diverticulitis. This disease is the outpocketing in the walls of the _______________________ due to weakened __________________________.
One of the dangers of diverticulitis is the bursting of an outpocket which spills the
contents of the large intestine into the abdominal cavity and causes peritonitis.

Aren't you glad someone else is willing to be a proctologist?

You are a success story, if you learn this chapter.