Fill in the blanks with appropriate words.
The nerves carrying impulse messages from the central nervous system to the effectors are called .......... , while those carrying sensory messages to the central nervous system are called ..........

Nerve which carries nerve impulse from tissue to central nervous system is called

1. 
   1 and 3 only
2. 
   1 and 2 only
3. 
   1 only
4. 
   1, 2 and 3

The system that carries nerve impulses back and forth between the central nervous system and the skeletal muscles, skin and sensory organs is called ___