Identify typical challenges as well as proven best
practices within public service organizations. Using both course material and outside academic sources,
students are expected to compare and contrast theories of organizational processes and offer suggestions
for a best-practice model.
- Identify, explain and give examples of at least 3 typical challenges faced by public service organizations
- For each challenge, present a best practice model designed to address the challenge
- All examples and best practices must be supported by course materials and outside academic
Action potential generated in axons is propagated to either direction from its site of origin. Intracellular current flows from the active zone where the inner cell membrane is positively charged compared to adjacent inactive membrane which is negatively charged. An opposing current flows through the extracellular fluid from the inactive to active region. This local current depolarizes the adjacent inactive regions, thus resulting in impulse propagation bidirectionally along the axon. The physiologic impulses, however, arise at one end of the axon i.e., the cell body or sensory terminal and are conducted only orthodromically. In pathological conditions, however, this order of conduction is not maintained. In the myelinated fibers, the conduction is much faster than the unmyelinated. In normal myelinated axons the impulse propagated by saltatory conduction. Saltatory conduction has been compared with a kangaroo travelling at speed. The action potential advance at near uniform velocity, but it is powered by discrete kicks of inward membrane current at the nodes of Ranvier. For rapid conduction, the intermodal distance should be great enough to maximize the jump of the action potential and reduce the loss of current at the node of Ranvier. In myelinated fibers the time required for the local current to excite the next node depends on the longitudinal resistance of the axoplasm, capacitance, and conductance of the intermodal membrane. With high value of these parameters, more current is dissipated before impulse reaches the next node. This results in longer time for the impulse to depolarize the adjacent node, which is responsible for the slower conduction. Myelin thickness is inversely related to internodal capacitance and conductance. Conduction velocity, therefore, increases with the increase in myelin to a certain point. In segmental demyelination or during remyelination, myelin sheath is thin, intermodal distance shorter, internodal conductance and capacitance is increased. These result in greater loss of local current before reaching the next node of Ranvier. The failure to activate the node of Ranvier results in conduction block. In case of a partial conduction, the impulse propagation is slowed due to longer time required by the dissipating current to generate an action potential. In segmental demyelination of smaller fibers the conduction may become continuous instead of saltatory. Impulse conduction in unmyelinated fibers occurs in a continuous manner which accounts for slower conduction velocity compared to saltatory conduction in myelinated fibers. The conduction velocity also slows down in focal compression, which may be due to demyelination and decrease in fiber diameter. (Mishra & Kalita ,2006).The loss of myelin is associated with delayed or blocked conduction in the demyelinated axons. Normal conduction of action potentials relies on the insulating properties of myelin. Thus, defects in myelin can have major adverse neurological consequences. Loss of myelin leads to leakage of K+ through voltage-gated channels, hyperpolarization, and failure to >GET ANSWER