I 



CHAPTER VIII 



SUMMARY OF THE FROG 



T has now been seen that the frog is a cold-blooded animal, an am- 

 phibian, and a vertebrate. 



Its external features have been observed. 



Its internal structure, consisting of a series of organs known as 

 systems, have been studied. These were : 



(a) The Digestive System. 



(b) The Circulatory System. 



(c) The Respiratory System. 



(d) The Excretory System. 



Concerned with Metabolism. 



(e) The Nervous System. T Concerned with regulation 



(f) The Endocrine secretions. J and control. 



(g) The Muscular System. Y~, , . a1 1 



)i \ -ri 01 1 j. 1 c> i [Concerned with locomotion, 



(h) The Skeletal System. r , 



; .( ^, T 1 \ support and protection. 



(1) I he Integumentary System.^ 



(j) The Reproductive System. Concerned with the propaga- 

 tion of the race. 



It has been learned that organs are composed of tissues, and tissues 

 in turn, of sheets of similar functioning cells. 



There were four general types of tissues : 



(a) Epithelial. 



(b) Connective. 



(c) Muscular. 



(d) Nervous. 



Tissues may also be classified according to their functional and 

 structural character. For example, according to function, the epithelium 

 is grouped as follows : 



(a) Glandular, which consists of secreting cells. 



(b) Sensory, which consists of sensory nerve cells and their 



fibers. 



(c) Germinal, which consists of those cells having especial 



growth or reproductive ability. 



(d) Protective, which goes to make up an outer covering of 



an organ or of the body itself. 



