196 



ELEMENTARY PHYSIOLOGY 



SUMMARY. 



(Not localised. 

 No special organs concerned. 

 Examples: pain, warmth, hunger, fatigue, 

 faintness, muscular sense, &c. 

 SENSATIONS -( / Touch Special organ the skin, tongue, 



and lips. 



Special J Smell Special organ the nose, 



senses ] Taste ,, ,, the tongue. 



I Hearing ,, ,, the ear. 

 x Sight ,, ,, the eye. 



i I. The irritation of sensory fibres. 



2. The transmission of this irritation to the 



brain. 



3. The translation of the irritation into a 



state of consciousness. 



CONDITIONS NECESSARY 



SENSATIONS 



NERVE-ENDINGS 



(Objective Caused by irritation produced by outside 

 objects. 

 Subjective Caused by a disturbed condition of the 

 cerebrum. 



, Terminal filaments probably ending in the cells of 



I the skin. 



I Pacinian bodies visible to naked eye in the skin 



of the hands and feet. 



I Touch corpuscles smaller abundant in highly sen- 

 ^ sitive parts of skin. 



SENSITIVENESS OF SKIN 



depends on 



f Thinness of the epidermis. 



1 The number of nerve-enJings in a given area. 



QUESTIONS ON LESSON XXXIII. 



1. What is the difference between common and special sensations? Give 



examples of each. 



2. What is meant by muscular sense ? Give an illustration. 



3. What are the conditions necessary to produce a sensation ? Give examples 



of sensations produced without the aid of a special organ of sense. 

 4.. May the sensation of sight be produced without the use of the eye ? If so, 

 how? 



5. What is meant by the terms subjective and objective as applied to sensations ? 



6. On what does the sensitiveness of the skin depend ? 



7. Describe the various modes of the termination of nerve fibres in the skin. 

 8- What do we mean by saying that the lips are more sensitive to touch than 



the arm ? How may this be proved ? 



