The Nervous System

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Cards (24)

  • Nervous system
    Made up of neurons (nerve cells), which go to all parts of the body
  • Sensory receptors
    • Detect different stimuli, e.g. light, sound, touch, temperature
  • Sense organs are what detect stimuli from the environment e.g. nose, tongue, ears
  • Receptors in the sense organs are connected to the CNS, which is made up of the brain and spinal chord
  • The brain and spinal chord make sense of information sent by the nerves and co-ordinate a reaction
  • The skin is a sense organ and its receptor cells are pressure and temperature, the stimulus being pressure and heat
  • The tongues receptor cell is taste and the stimulus is from a chemical
  • The nose receptor cells are smell and taste and their stimulus are chemicals
  • Neurone - 1 nerve cell
    Nerve - A bundle of nerve cells
  • Nerve cell diagram
    A) dendrite
    B) nucleus
    C) axon
    D) cytoplasm
    E) cell membrane
    F) nerve ending
  • Nerve cells have branched dendrites to pick up impulses and transmit them from one nerve into the other
  • The fatty sheath insulates the axon of the nerve cell to contain electrical impulses to protect them and allow faster transmission
    • Relay neurons connect the sensory and motor neuron at the CNS
    • Sensory receptors send impulses to the CNS
    • Motor neurons send the impulse to the muscle for them to relax or contract based on the decision of the CNS
  • 3 main stages of a nervous response
    • Stimulus - Change in environment e.g. pressure on skin
    • Stimulus detection - Sensory receptors detect stimulus and transmit impulse along the axon
    • Response from effectors - Response signal transmitted along axon of motor neuron to motor end plate, then effectors e.g. muscles, glands
  • Each nerve cell
    A) sensory neuron
    B) relay neuron
    C) motor neuton
  • Synapase is the place where impulses are transmitted between two nerve cells, or between gland or muscle cells