Escape reflex, a kind of escape response

Escape response

Escape response, escape reaction, or escape behaviour is a possible reaction in response to stimuli indicative of danger, in particular, it initiates an escape motion of an animal...

, is a simple reflectory reaction in response to stimuli

Stimulus (physiology)

In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....

 indicative of danger, that initiates an escape motion of an animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

.

Escape reflexes control the seemingly chaotic motion of a cockroach

Cockroach

Cockroaches are insects of the order Blattaria or Blattodea, of which about 30 species out of 4,500 total are associated with human habitations...

 running from under the foot when one tries to squash it.

In higher animals examples of escape reflex include the withdrawal reflex

Withdrawal reflex

The withdrawal reflex is a spinal reflex intended to protect the body from damaging stimuli...

, e.g., the withdrawal of a hand in response to a pain

Pain

Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

 stimulus. Sensory receptor

Sensory receptor

In a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...

s in the stimulated body part send signals to the spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

 along a sensory neuron

Sensory neuron

Sensory neurons are typically classified as the neurons responsible for converting external stimuli from the environment into internal stimuli. They are activated by sensory input , and send projections into the central nervous system that convey sensory information to the brain or spinal cord...

. Within the spine a reflex arc

Reflex arc

A reflex arc is a neural pathway that controls an action reflex. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord...

 switches the signals straight back to the muscles of the arm (effector

Effector

Effector may refer to:*An actuator, in robotics*Effector , a music album by the Experimental Techno group Download*Effector cell, a type of lymphocyte in immunology...

s) via an intermediate neuron (interneuron

Interneuron

An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways...

) and then a motor neuron

Motor neuron

In vertebrates, the term motor neuron classically applies to neurons located in the central nervous system that project their axons outside the CNS and directly or indirectly control muscles...

; the muscle contracts and the arm jerks. Only three nerve cells are involved, and the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 is only aware of the response after it has taken place.

Escape reflex arcs have a high survival value, enabling organisms to take rapid action to avoid potential danger.

Various animals may have specialized escape reflex circuits.

Examples of escape reflexes

• Withdrawal reflexes
  • Ducking (flexing the neck to protect the head)
  • Jumping at loud sounds
  • Withdrawal of a body part when it touches something excessively hot or cold.
• Other
  • Lateral giant escape
    Lateral giant neuron
    The lateral giant interneuron is an interneuron in the abdominal nerve cord of crayfish. It is part of the system that controls a special kind of escape reflex of crayfish....
    
     in crayfish
    Crayfish
    Crayfish, crawfish, or crawdads – members of the superfamilies Astacoidea and Parastacoidea – are freshwater crustaceans resembling small lobsters, to which they are related...
    
    
  • Escape reflex in squid
    Squid giant axon
    The squid giant axon is the very large axon that controls part of the water jet propulsion system in squid. It was discovered by English zoologist and neurophysiologist John Zachary Young in 1936...
    
    
  • Dorsal ramp interneuron (DRI) action in Tritonia molluscs.
  • C-start in fish
    Fish
    Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
    
     and amphibia