biology 1 chapter 2.1

Responding to change 

• The nervous system allows humans to react to their surroundings and coordinates behaviour.
• Receptors detect external stimuli.
• Electrical impulses pass to the brain along neurons.
• The brain coordinates responses.

Receptors can be found in the sense organs- eyes,ears,nose,tongue ans skin

Reflex actions

• Reflex actions are rapid, automatic responses to a stimulus 
• Reflexes protect us from damage 

A receptor detects a stimuli...A sensory neuron transmits the impulse to the CNS...A relay neuron passes the impulse on...A motor neuron is stimulated....The impulse passes on to an effector...Action is taken 

Hormones and the menstral cycle

• The menstural cycle takes 28 days with ovulation about 14…