Chapter control and coordination -----Class X

Q 1 What is the difference between nervous control and chemical control?

A Nervous control
1 Its response is immediate and short lived .
2 Information is passed as electro chemical  conduction.
3 It travels only to place where nerve is present

Chemical control
1 Information travels slow
2 Information is passed as chemical substance through blood stream.
3 Response is also very slow and effects are sometimes prolonged

 Q 2 Draw the labelled diagram of nerve cell .




Q 2 Explain how the information travels through neurons .

A The  sensory organs receive information and start a chemical signal which enters at the tip of dendrite and sets off an electrical impulse which moves from cell body to axon and nerve endings.At the nerve ending electrical impulse is converted back to chemicals called neurotransmitters .These chemicals jump the gap (synapse)between the root of previous nerve and dendrite  of next nerve cell to start the same reaction till it reaches the destination..

Nerve impulse
Dendrite------>cell body------>Axon----->nerve ending at the tip --->synapse------>tip of dendrite


Q3 Name the sensory organs .
A Eyes ---vision ,Nose----olfactory ,tongue----gustatory,ear -----auditory,  Skin---tactile

Q4 What is the difference between sensory and motor neuron?
A The neurons which take sensations from sensory organs to central nervous system ie brain or spinal cord are called sensory while the neurons that take orders from CNS to muscles for necessary actions are called motor neuron.

Q5 Can messages travel back from dendrite to root of nerve cell ?
A Never!!! they always travel from root to dendrite as there are neurotransmitters produced from root that jump synapse and move to dendrite and never vice -versa.