The activity of our body is regulated nervous systemensuring consistency and order.
A person cannot think over his every move, it is too long and costly in terms of energy, therefore, a significant part of the functions is carried out with the help of reflexes that have a complex, but effective mechanism.
What is a receptive reflex field?
The receptive reflex field is the zone in which the maximum number of sensitive cells that cause a reflex reaction are concentrated. Each type of reflex has its own receptor localization, which ensures optimal perception of information. So, the receptive field of the swallowing reflex is concentrated in the root of the tongue and soft palate, and in the knee - in the area under the patella.
In addition to action, reflexes also regulate the position of a person in space, the fields of static reflexes located in the vestibular apparatus, muscles and skin are responsible for this. They transmit a signal about the state of the body relative to the surrounding environment, resulting in flexion or extension of muscles, a change in body position.
The receptor fields include the first part of the reflex arc - the perceiving one, then the mechanism for transmitting and processing information is switched on, which allows the corresponding physiological reaction to be carried out.
Synapse types
To transmit the signal further, contact must be made between nerve cells - neurons, this process is carried out using synapses:
- they can be simple or complex in structure;
- by location: axodendritic (interacting with another dendrite), axonal (interacting with the axon of another cell);
- in terms of functionality - exciting and inhibiting;
- by the mechanism of action - electrical or chemical, or a combination of both.
Transfer of excitement through the synapse
The reaction takes place through chemicals and an electrical impulse. Inside the synapses are vesicles with a mediator - a substance that can cause excitation in the next cell. When the signal reaches the synapse, its membrane depolarizes, calcium channels open, and calcium ions penetrate into the presynaptic membrane, activating the vesicles with a mediator.
This leads to depolarization at the postsynaptic membrane and the excitation of its potential. The signal goes to the next cell. This process takes place very quickly, while the signal can be summed up, and its strength depends on the volume of involved mediators. The more there are, the faster and stronger the signal and the corresponding reaction will be.
Reflex time
The period from the moment of irritation to the manifestation of a response is called reflex time. It directly depends on the number of synapses in reflex arc and numbers interneurons. Monosynaptic arcs usually have the shortest reflex times.
Reflexes spinal cord and their receptive fields are indispensable elements that help the body to interact with the environment and control the internal state. With their violations, the body cannot adequately respond to the impact, which can lead to its death.
