Cellular Organization of Plants and Animals 61 



IV. SYSTEMS 



A system is an association of different organs which perform a specific 

 function. For instance, the digestive system consists of such organs as 

 the tongue, teeth, saHvary glands, pharynx, esophagus, stomach, large 

 and small intestines, liver, pancreas, and the gall bladder. 



QUESTIONS AND TOPICS 



1. Define (1) tissue, (2) organ, and (3) system. 



2. What role does heredity play in the process of tissue formation? 



3. Give the distinguishing characteristics and location of the following tissues: 



(1) epithelial, (2) nervous, (3) connective, and (4) muscular. 



4. In nervous tissue describe the structure and functions of (1) neuron, (2) 

 dendrite, (3) axon, (4) synapse, (5) nerve, (6) nerve pathway, (7) ganglion, 

 and (8) brain. 



5. Why is blood considered a tissue? How does it differ from other tissues? 

 Should it be classed with the connective tissues or separately? Why? Why 

 might blood be called a compound rather than a simple tissue ? 



6. Contrast and give examples of involuntary and voluntary muscle tissues. Do 

 involuntary muscles react without a stimulus ? Why should the muscles of 

 the heart be involuntary ? Which of the three groups of muscles are striated ? 



7. Do you consciously send impulses to your skeletal muscles when you walk? 



8. What types of muscles are used in each of the following: (1) breathing, 



(2) pumping blood, (3) swimming, and (4) digesting foods? 



9. Explain what happens in muscles when a so-called habit has been formed. 



10. Contrast animal tissues with plant tissues. Which plant tissues perform 

 functions which resemble those performed by animal tissues ? Give specific 

 examples. 



11. What role does mitosis play in the development of tissues? 



12. Give the distinguishing characteristics and functions of each kind of plant 

 tissue. 



SELECTED REFERENCES 



Cameron: Tissue Culture Technique, Academic Press, Inc. 



Child: Individuality in Organisms, University of Chicago Press. 



Cowdry: General Cytology, University of Chicago Press. 



Dawson: Lambert's Histology, The Blakiston Co. 



Elwyn and Strong: Bailey's Textbook of Histology, Williams and Wilkins Co. 



Haden: Principles of Hematology, Lea & Febiger. 



Maximow and Bloom: Histology, W. B. Saunders Co. 



Nonidez and Windle: Histology, McGraw-Hill Book Co., Inc. 



Sharp: An Introduction to Cytology, McGraw-Hill Book Co., Inc. 



Sharp: Fundamentals of Cytology, McGraw-Hill Book Co., Inc. 



Stiles: Handbook of Microscopic Characteristics of Tissues and Organs, The 



Blakiston Co. 

 Weiner: Blood Groups and Transfusions, Charles C Thomas, Publisher. 



