nervous system

Question 1

what does the central nervous system consist of

Answer 1

the brain and the spinal cord

Question 2

explain the role of the receptor cells to effectors via the central nervous system

Answer 2

receptor cells detect the stimulus
receptor cells then send electrical impulses down neurons to the central nervous system (coordination centre)
the CNS now sends electrical impulses down other neurons to effectors
effectors then bring about responses

Question 3

name the 2 most common types of effectors

Answer 3

muscle cells (which contract)
glands (which secrete hormones)

Question 4

explain the process of the reflex arc

Answer 4

• when you touch a hot object the stimulus (heat) is detected by the receptor (skin)
• electrical impulses now pass from the receptor along to the SENSORY NEURONE to the central nervous system (CNS)
• at the synapse a chemical is released which chemically diffuses across a RELAY NEURONE in the central nervous system where it triggers an electrical impulse
• the electrical impulse now travels across the RELAY NEURONE and reaches another synapse which chemically diffuses
  this triggers an electrical impulse in a MOTOR NEURONE
  the electrical impulse now travels down the MOTOR NEURONE to an effector
  the effector is a muscle (the muscle contracts pulling the and away from the heat)