flowchart LR
A["系统观"] --> B["管道层"]
A --> C["开关层"]
A --> D["外挂件"]
B --> B1["循环"]
B --> B2["呼吸"]
B --> B3["消化"]
B --> B4["泌尿"]
C --> C1["神经调节"]
C --> C2["内分泌轴"]
D --> D1["药理 ADME"]
style A fill:#e3f2fd
style B fill:#fff3e0
style C fill:#e8f5e9
style D fill:#f3e5f5