Let's study the involvement of enzymes in the human digestive system. Read the pages indicated by B-25.  Digestion in most animals occur extracelluarly  in a digestive sac or system.  Enzymes are secreted into various cavities where they will break down various food substances. Enzymes hydrolyze various foods into their monomers in order for them to be absorbed into the bloodstream and transported throughout the body. You may want  to review hydrolysis of macromolecules which was presented in miniunit Alpha. Click here. 
 
Study the table in the text indicated by B-26. In your notes write out the answers to behavioral objectives 32, 34 and 35. Copy the table below in your notes and fill in the blank columns. 
. 

SOURCE OF SECRETION         SECRETION                         ROLE IN DIGESTION 

salivary glands
stomach lining
pancreas
liver
small intestine lining

 

13. Where in the digestive system is the major site of nutrient absorption into the blood? 

a) large intestine               d) liver 
b) stomach                       e) pancreas 
c) small intestine 
 
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14. Where in the digestive system is the major site of water absorption  into the blood? 

a) large intestine               d) liver 
b) stomach                       e) pancreas 
c) small intestine 
 
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In your notes write the effects that hydrochloric acid performs in your stomach (B.O. 33): activation of pepsin, kills bacteria, breaks down large food substances. 
 

15. The hormone responsible for stimulating secretion of hydrochloric acid by stomach cells is: 

a) pepsin                               d) gastrin 
b) cholecystokinin                  e) insulin 
c) secretin 
 
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In your notes write a paragraph explaining the role of the liver and gall bladder during digestion. Include make-up of bile salts, where stored, effect of lipids. Study behavioral objectives 36 and 37. 
 

Learn how the pancreas islets control blood glucose levels in the human body by reading the pages indicated by B-27 (B.O. 38). Write a paragraph in your notes describing blood glucose regulation (include insulin, glucagon, pancreas, glycogen, high and low blood glucose levels). 
 
 
16. Where is insulin produced in the human body and  what does it induce? 

a) liver,  induces the gall bladder  to convert glucose into glycogen and body cells  
    to   burn glucose 
b) pancreas, induces the liver to burn glucose and  body cells  to convert 
    glucose  into glycogen 
c) liver, induces the pancreas to convert glucose into glycogen and body cells  to 
    burn  glucose 
d) pancreas, induces the liver to convert glucose into glycogen and body cells  to 
    burn  glucose 
e) stomach, induces the duodenum to convert glucose into glycogen and body cells 
    to  burn glucose 

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17. Where is glucagon produced in the human body and  what does it induce? 

a) liver,  induces the gall bladder  to convert glucose into glycogen and body cells  to 
    burn glucose 
b) pancreas, induces the liver to convert glycogen into glucose and  body cells  to 
    burn fat 
c) liver, induces the pancreas to convert glucose into glycogen and body cells  to 
    burn glucose 
d) pancreas, induces the liver to convert glucose into glycogen and body cells  to 
    burn glucose 
e) stomach, induces the duodenum to convert glucose into glycogen and body cells 
    to burn glucose 
 
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This is the end of miniunit Beta. Go back to the home page and examine the www pages concerning miniunit Beta. The may be found in the resource section. You may now take the practice test for miniunit Beta. Click her to go back to the Biology 108N home page and review or take the practice test.  Good Luck! 
 
 
 
 
 
 
 
 
 

  
 
 
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