Neurons and synapses
Organization of the Nervous System
• Central nervous system (CNS)– Brain– Spinal cord
• Peripheral nerves
Sensory and motor neurons
• Sensory neurons– Carry nerve impulses from to the CNS
• Motor neurons– Carry impulses from the CNS to effectors – effectors (muscle and gland cells)
• Relay neurons– Carry impulses within the CNS– between neurons
Structure of a motor neuron
Synapses
Synapse- Junction between two neurons
• Messages are passed across the synapse in the form of chemicals - Neurotransmitters
Stages in synaptic transmission
http://www.youtube.com/watch?v=z3F5dfmQ3hkhttp://www.youtube.com/watch?v=9nUY6o-LCWY
Vocabulary• Central nervous system (CNS): part
of nervous system that consists of the brain and spinal cord, regulating the body’s responses to external and internal stimuli
• Neurons: cells in the central nervous system that can carry messages at high speed in the form of electrical impulses.
• Spinal cord: a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain
• Peripheral nerves: nerves that connect all parts of the body to the central nervous sytem
• Sensory neurons: neurons that carry nerve impulses from sensory cells (receptors) to the CNS
• Motor neurons: neurons that carry impulses from the CNS to effectors (muscle and gland cells)
• Relay neurons: neurons that carry impulses within the CNS, from one neuron to another
• Axon: a long, slender projection of a neuron that conducts electrical impulses away from the neuron’s cell body (soma)
• Dendrites: the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to soma
• Neurotransmitters: endogenous chemicals which transmit signals from a neuron to a target cell across a synapse
• Depolarization: a change in cell’s membrane potential, making it more positive, or less negative
• Vesicles: a small membrane-enclosed sac that can store or transport susbstances