430 - Multicellular Animals, Especially Man 



TEST QUEST 



1. How many kinds of receptors are present in 9. 

 the skin? How is it possible to find where 

 these receptors are localized in any given 

 area? 10. 



2. How do pain receptors differ from most 

 other kinds of sensory cells? 



3. What is the justification for regarding the 11. 

 eye as a chemoreceptor and the ear as a 

 mechanoreceptor? Explain. 



4. Make a labeled diagram to show all essen- 12. 

 tial structures in the human eye and state 



the function of each labeled part. 



5. Differentiate between each pair of terms: 13. 



a. the blind spot and the fovea centralis 



b. rods and cones 



c. the cornea and the lens 



d. the choroid and sclerotic coats 



e. the pupil and the iris 14. 



f. a statocyst and a statolith 



g. the labyrinth and the cochlea 



6. Differentiate between black-white and color 

 vision on the basis of the basic receptors and 



on the basis of the photochemical reactions 15. 

 that are involved. 



7. What is meant by the term cis-trans change 

 of molecular configuration? 



8. Explain why a dark-adapted retina is so ex- 

 ceedingly sensitive. 



IONS 



Explain the statement that accommodation 

 for near vision demands work on the part 

 of one of the eye muscles. 

 Explain the fact that the eyes of older indi- 

 viduals suffer a loss in their capacity to ac- 

 commodate. 



Explain the functioning of: (a) the saccule 

 and utricle; (b) the semicircular canals: (c) 

 the cochlea. 



Specify two types of proprioceptors and ex- 

 plain the importance of the proprioceptors 

 in relation to our muscular movements. 

 When a warm object is handled, what factors 

 account for a person's capacity to judge: (a) 

 the degree of warmth: (b) the size of the 

 warm object: (c) the relative position of the 

 object? 



(a) 'What is a generator potential? (b) How 

 does it differ from an action potential? (c) 

 ■What techniques have made it possible to 

 measure these potentials in small unicellular 

 receptors? 



Explain how the intensity of stimulation is 

 related to the magnitude of the generator 

 potential and to the frequency of nerve im- 

 pulses in the volle\ of discharges. 



FURTHER READINGS 



1. Smell, Taste and Allied Senses in the Verte- 

 brates, by G. H. Parker: Philadelphia, 1922. 



2. Vision, by S. H. Hartley; New York, 1941. 



3. Hearing, Its Psychology and Physiology, by 

 S. S. Stevens and H. Davis: New York, 1938. 



4. "How Cells Receive Stimuli," by W. H. Mil- 

 ler, F. Ratliff, and H. K. Hartline; in Scien- 

 tific American, September 1961. 



"The Initiation of Impulses in Receptors." 



by Donald Kennedy; in American Zoologist, 



February 1962. 



The Chemical Ei'ohttion of Vision, by George 



Wald; Hanev Lecture Series; New York, 



1945-1946. 



