NOTE: response of receiving cell to neurotransmitter depends on: Nature of cell itself Location of cell in nervous system Particular neurotransmitter involved Neurotransmitter then deactivated by enzymes located on membrane + reabsorbed, recycled + repackaged cell junction between (end of axon) of 1 Synapse synaptic terminal – neurone + dendrites of target cell (another neurone or effector cell) NOTE: because synaptic vesicles (containing neurotransmitters) are only found at end of axon, synapse ensures that nerve impulse can only flow in 1 direction along neurone pathway NOTE: signals are regarded as: Electrical because they can be detected as changes in voltage – Chemical because it is the relative movement of charged atoms (ions), – across neurone membrane that causes the signal i.e. Na, K, 3 types of neurones: transmit impulses from receptor to CNS Sensory neurones – transmit impulses from CNS to neurones – effector (also called association or Interneurones connector neurones) located within CNS + carry – impulses from sensory to motor neurones bundle of neuronal fibres (axons) Nerve – Blood vessels supply blood (neurones require considerable energy + nutrients to operate) Connective tissue helps hold fibres together
NOTE: response of receiving cell to neurotransmitter depends on: Nature of cell itself Location of cell in nervous system Particular neurotransmitter involved Neurotransmitter then deactivated by enzymes located on membrane + reabsorbed, recycled + repackaged Synapse – cell junction between synaptic terminal (end of axon) of 1 neurone + dendrites of target cell (another neurone or effector cell) NOTE: because synaptic vesicles (containing neurotransmitters) are only found at end of axon, synapse ensures that nerve impulse can only flow in 1 direction along neurone pathway NOTE: signals are regarded as: Electrical – because they can be detected as changes in voltage Chemical – because it is the relative movement of charged atoms (ions), i.e. Na, K, across neurone membrane that causes the signal 3 types of neurones: Sensory neurones – transmit impulses from receptor to CNS neurones – transmit impulses from CNS to effector Interneurones (also called association or connector neurones) – located within CNS + carry impulses from sensory to motor neurones Nerve – bundle of neuronal fibres (axons) Blood vessels supply blood (neurones require considerable energy + nutrients to operate) Connective tissue helps hold fibres together