Created by Susan Stagg-Williams, Dieter Andrew Schweiss, Gavin Sy, and H. Scott Fogler, 1994
Updated by Apeksha Bandi, Gustav Sandborgh, and Arthur Shih, 2013
Cobras have several methods for delivering their deadly venom to their prey.
Some cobras can spit their venom into a victim's eyes, causing extreme pain
and blindness. However, the most common and well known method of venom delivery
is injection into a victim's body through their bite.
A cobra striking
Cobras belong to the sub-group of snakes known as elapids; there
are over 270 species of cobras and their relatives. An elapid's venom
contains postsynaptic neurotoxins that spread rapidly in its victim's
bloodstream, causing respiratory failure and, eventually, death.
Cobra venom is an example of a molecule that prohibits the interaction of
acetylcholine molecules (transmitted from nerve endings surrounding the
diaphragm muscle) with the receptor sites on the diaphragm muscle. (See
the section on Human Respiration for more
details). It binds to the receptor sites, blocking them from interacting
with acetylcholine molecules. Even worse, the venom molecule will not
immediately break down and vacate the receptor site, effectively removing
the site from active duty.
It has been determined that even if 85 to 90% of the receptor sites on
your diaphragm become blocked by venom, you will cease breathing. With
cobra venoms, this process can take as little as 30 minutes. The only way
to counteract the effects of cobra venom (or most other poisonous snake
venoms) is to inject the appropriate antivenom shortly after the bite
occurs. If antivenom is unavailable, your life can still be saved by
putting you on an artificial respirator until the paralysis of the
diaphragm muscle wears off.
(If this watered-down explanation of effects of cobra venom wasn't enough
for you, then check out a more-detailed explanation
of the effects of cobra venom.)