Reflex action
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Definition
A stereotyped (involuntary) motor response elicited by a defined stimulus. 1
Explanation
A reflex action or reflex is a biological control system linking stimulus to response and mediated by a reflex arc. Reflexes can be built-in or learned.
Reaction time
For a reflex, reaction time is the time from the onset of a stimulus until the organism responds.
Mechanism
A reflex mechanism involves a receptor organ, and effector organ, and some type of communication network.
Ivan Pavlov unintentionally launched the study of conditioning by establishing a way of producing what he called "conditional reflexes", i.e. reflexes that would only be seen conditional on previous experiences of the subject.
Reflex actions seen in adult humans include:
- Accommodation reflex
- Achilles reflex
- Anocutaneous reflex
- Babinski reflex
- Biceps stretch reflex
- Brachioradialis reflex
- Crossed extensor reflex
- Mammalian diving reflex
- Gag reflex
- Gastroc-Soleus reflex
- Patellar reflex (knee-jerk reflex)
- Photic sneeze reflex
- Pupillary reflex
- Quadriceps reflex
- Salivation
- Sneeze
- Triceps stretch reflex
- Vestibulo-ocular reflex
- Withdrawal reflex
Processes such as breathing, digestion and the maintenance of the heartbeat can also be regarded as reflex actions, according to some definitions of the term.
Newborn babies have a number of other reflexes which are not seen in adults, including:
- suckling
- hand-to-mouth reflex
- Moro reflex, also known as the startle reflex
See also
- Autonomic nervous system
- Sensory system
- Spinal nociceptive reflex
External links
References
Note 1: Purves (2004). Neuroscience: Third Edition. Massachussets, Sinauer Associates, Inc.