MULTICELLULAR ANIMALS 



223 



Name 

 Olfactory 



Optic 



Oculo-motor 



Trochlearis 



Trigeminus 



Cranial Nerves 

 Origin on Brain Terminus 



Cerebral hemi- 

 spheres 



Floor of dienceph- 

 alon 

 Base of mid-brain 



Membrane of internal 



nares 



Retina of eye 



Eye muscles 



Function 

 Sense of smell 



Sense of sight 



Abducens 



Anterior margin of Superior oblique eye 



hind-brain muscle 



Medulla oblongata (ist branch) Integument Sensory 



of forehead, eyelids, la- 

 chrymal glands 



(ind branch) Upper jaw, Sensory 

 upper teeth, roof of 

 mouth, etc. 



(3rd branch) Mastica- 

 tory muscles, lower jaw 

 and teeth, lower lip 



Medulla oblongata Lateral eye muscles 



Motor. Movement 

 of eyeballs (p. xx6) 

 Motor. Movement 

 of eyeballs (p. 2.16) 



Motor and sensory 



Motor. Movement 

 of eyeballs (p. 1x6)- 

 Motor 



Facial Medulla oblongata Facial muscles 



Auditory Medulla oblongata Organ of equilibrium and Sensory 



organ of sound reception 



in ear 

 Glossopharyngeal Medulla oblongata Pharynx, part of tongue, Sensory and motor 



parotid gland 

 Vagus Medulla oblongata Pharynx, trachea, oeso- Sensory and motor 



phagus, viscera 

 Spinal accessory Medulla oblongata Muscles of neck, viscera Sensory and motor 

 Hypoglossal Medulla oblongata Muscles of tongue Motor 



Receptors: Chemical Senses. While a nerve may be stimu- 

 lated by artificial means at any place along its course, for the recep- 

 tion of outside stimuli the sensory nerves of the animal body end in 

 specialized sense or receptor organs. In general, in the higher 

 animals these receptors are grouped into five main types and their 

 responses are known as the Special Senses. The sense of smell, 

 0LF.\CT0RY SENSE, and the sense of taste, gust.\tory sense, are con- 

 sidered together as chemical senses, since both are activated by 

 chemicals, in the air, water, or materials entering the mouth. The 

 nerve endings that receive the stimuli recognized as smell and as 

 taste are equipped with specialized structures; those of smell are 



