Complex sentence: Systemic toxicity of local anesthetics can be described by the direct effects on the immune system, blood (hematologic), central nervous system, and cardiovascular system.
Split into simpler sentences: Systemic toxicity of anesthetics involves the central nervous system (CNS), the cardiovascular system, and the immune system. It can be described by the direct effects on the immune system, blood (hematologic), and cardiovascular system.