How does a reflex work?

Reactins are sometimes mindless - reflexes at a glance 

One cannot control reflexes, such as B. the cough reflex, because these are will-independent reactions to a certain stimulus. Reflexes serve z. B. the rapid averting of dangers and the regulation of various body functions (such as muscle relaxation). There are two types of reflexes - the innate reflex and the acquired reflex.

1. Innate reflexes are subdivided again - into self-reflex and external reflex. In the self-reflex, the stimulus and the reaction are in the same organ and only one synapse is addressed. Reflexes serve z. B. the rapid averting of dangers and the regulation of various body functions (such as muscle relaxation). Several synapses are addressed in the external reflex. The stimulus and the reaction to it lie in different organs. The reaction time to the stimulus is high. An example of an external reflex is pulling the hand away after a painful stimulus on the finger.
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2. The acquired stimuli are learned. They are the basis of innate stimuli. It is therefore a constant learning process. However, just as one can learn these stimuli, one can also unlearn them again.

This is how a reflex works in the body

The reflex center is in the spinal cord. The spinal cord emerges from the elongated medulla at the level of the large occipital opening on the brain and extends in the vertebral canal up to the level of the Intervertebral disc between the first and second lumbar vertebrae. Over its entire length, a total of 31 pairs of nerve roots arise on both sides at regular intervals, each of which unites to form the sinal nerves. This divides the spinal cord into 31 segments, each with its own reflex and connection centers. A reflex works via so-called reflex arcs.

1. A receptor works similarly to a socket with a plug. A stimulus is transmitted here. This can be done either from an organ or other parts of the body.


Afferent nerves

Afferent and efferent nerves have different roles. Submit the former ...

2. Highly sensitive nerve fibers transmit this stimulus to the central nervous system. This can be compared to a fiber optic cable, which transmits signals on the Internet at ultra-fast speeds.
3. The stimulus triggers a reaction, which reaction that is is determined in a reflex center in the central nervous system.
4. The reaction is now transmitted to the executive body.
5. The corresponding reaction is now carried out. This can e.g. B. be a muscle.

Reflex arc of a self-reflex

This works in a similar way with self-reflexes, here the receptor and success organs are the same. Monosynapsic reflexes are self-reflexes, here the stimulus is only transmitted via an interface (synapse). A typical example is the diagnostically important patellar tendon reflex. The patellar tendon reflex works like this: The doctor gently hits the knee with a small hammer. The reflex action here is the twitching of the leg.

1. The excitation impulses reach the spinal cord via the spinal nerves.
2. The cell body of the conductive nerve cell is located in the spinal ganglion.
3. The excitation reaches the gray matter via the back root.
4. The switch to a motor nerve cell takes place in the anterior horn.
5. The excitation impulse leaves the spinal cord via the anterior root, runs back to the muscle in the spinal nerve and causes the reflex response there.