3. Blood Disorders. Blood disorders such as hemophilia and leukemia can cause unexplained bruising, often because your blood fails to clot properly. If you have severe and frequent unexplained bruising, it's a good idea to see a physician to rule out such disorders, especially if it seemed to come on suddenly.
Puffer fish contain the potent neurotoxin tetrodotoxin. TTX is thought to be synthesized by a bacterial or dinoflagellate species associated with the puffer fish. The toxin is concentrated in the liver, gonads, and skin. The level of toxicity is seasonal, and, in Japan, fugu is served only from October through March.
Tetrodotoxin: Mode of Action. The flow of sodium ions into nerve cells is a necessary step in the conduction of nerve impulses in excitable nerve fibers and along axons. Normal axon cells have high concentrations of K+ ions and low concentrations of Na+ ions and have a negative potential.t acts by blocking the conduction of nerve impulses along nerve fibers and axons. The victim eventually dies from respiratory paralysis. Tetrodotoxin is quite specific in blocking the Na+ ion channel and therefore the flow of Na+ ions while having no effect on K+ ions.