NEURONAL ORGANIZATION - DENDRITES -

• DENDRITES ARE RECEPTOR INPUT REGIONS OF NEURONS THAT INTEGRATE A NUMBER of INPUTS. Dendrites of neurons produce a spatial receptor field for receptors of chemical transmitters at synapses. These neuronal projections accommodate large numbers of diverse inputs for integration of neuronal signals arriving as excitation and inhibition.
• A second function is to gauge the electrotonic spread to the initial segment for initiation of the action potentials. These occur through cable properties.
• A third function of dendrites is to respond to ligand inputs that activate voltage gated calcium channels that produce dendritic spikes. These dendritic action potentials depolarize parts or the entire dendritic tree.

• NEURONAL DENDRITES

• Dendritic arbors- Widens the field of reception through spatial domains around branching patterns
• Arbor shapes are an important part of neuronal integration through input summation.
• Spines are present on dendrites as receptor isolating devices.
• Increased volume distribution along dendritic arbors can decrease resistance to electrotonic spread making synaptic inputs more responsive (cable properties)
• Neuronal integration- Synapse locations, synaptic source and type of ligands (Excitatory, inhibitory, modulatory) together integrate circuit responsiveness.