When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cells throughout the body (systemic chemotherapy).

Its ability to reach synapses and neuromuscular and neuroglandular junctions throughout the body is responsible for its PNS effects, whereas its ability to cross the blood-brain barrier confers upon it the ability to cause CNS effects.

Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body.

Systemic treatments can reach cancer cells throughout the body.

These devices are used in minimally invasive nonsurgical procedures to reach disease sites throughout the body via the circulatory system.