Final answer:
Neurons are optimized for excitability and conductivity due to their extended dendritic structures and myelin-insulated axons, which enable rapid communication within the nervous system.
Step-by-step explanation:
The two physiological characteristics that are highly developed in neurons (nerve cells) are their capacity for excitability and conductivity. Neurons are remarkable for their ability to respond to stimuli and to propagate an action potential along the axon to communicate with other neurons, muscles, or glands. The specialized structures that facilitate these functions are the dendrites, which receive signals, and the axon, which sends signals. The axon furthermore can be insulated by a myelin sheath, enhancing the speed of signal transmission.
Dendrites highly specialize in the interception of chemical signals from other neurons, leading to the initiation of an action potential within the neuron. The action potential then travels down the axon, which is designed for rapid signal transmission. The presence of myelin on many axons serves as an insulator, significantly speeding up this process and ensuring efficient communication within the nervous system.
Overall, the morphological adaptations such as extended dendritic structures and lengthy, insulated axons, make neurons exceedingly equipped to fulfill their role in receiving, processing, and transmitting electrochemical signals, which is crucial for the regulation of various physiological processes across the animal kingdom.