Final answer:
The statement about the syringe containing a harpoon is false; dental syringes use needles to administer anesthetics. If red blood cells burst, the solution was hypotonic, not isotonic. Injectable anesthetics prevent pain by disrupting ion movement in nerve cells.
Step-by-step explanation:
The statement that the syringe contains a harpoon to puncture the oral mucosa to allow the anesthetic to penetrate is false. A dental syringe used for local anesthesia is equipped with a needle, not a harpoon, to deliver the anesthetic into the oral tissues. The purpose of the needle is to deposit the anesthetic near a nerve or into the tissue to block sensation, thereby preventing pain during dental procedures.
When discussing isotonic saline solutions, if a patient's red blood cells had burst (hemolysis) as indicated in the autopsy, the injected solution could not have been isotonic. Instead, it was likely a hypotonic solution, which caused water to enter the red blood cells, leading to their rupture.
In the situation of dental anesthesia, injectable anesthetics such as local anesthetics are used to numb the target area. These anesthetics work by interfering with the passage of ions across the nerve cell membranes, thus inhibiting the transmission of nerve impulses and preventing the sensation of pain until the anesthetic effect wears off. Common local anesthetics include lidocaine and articaine.