Dual Innervation

Human anatomy > Autonomic Nervous System > Dual Innervation

The homeostatic ability of the body, which involves the internal balance of the human system, is dependent on dual innervations. Without this system, the body will not function properly. How do dual innervations work and what is their significance in the body?

Dual innervations

These are innervations affected by two systems, the parasympathetic and sympathetic nerve systems. They are both present in some organs because of the variety of functions that the organs have to perform. Both systems are anti-thesis to each other; their functions are opposites but exist in synergism with the body’s health and wellness. The parasympathetic nervous system is responsible for the “rest and digest” function of the body, while the sympathetic nervous system is responsible for the “fight or flight” function. The neurons of these two systems both exist in organs and act as the homeostatic basis of physiologic responses. Here are some specific examples of dual innervations.

Cooperative dual innervations

Cooperative dual innervations involve both sympathetic and parasympathetic nerve fibers working together to produce a response. One specific example is in coitus, wherein both female and male are aroused with the help of the sympathetic neurons. The act is then concluded in an orgasm, which involves your parasympathetic neurons. Both nerve fibers acted as one and cooperated to produce the sexual gratification of the couple. 

Antagonistic dual innervations

These types of innervations are demonstrated perfectly by the increase and decrease of the heartbeat. The heartbeat can increase higher than 80 beats per minute or bpm and lower than 60 beats per minute. The specific part of the heart that employs dual innervations is the sinoatrial node or SA node. This SA node functions as the pacemaker of the heart by the production of action potentials more quickly than other parts of the heart. The SA node, due to its voltage-gated calcium channels, stimulates the rest of the organ to respond.

Complementary Dual Innervations

These are dual innervations caused by the parasympathetic and sympathetic divisions that complement each other. The process of digestion demonstrates this perfectly. While the parasympathetic neurons initiate the production of salivary enzymes to start digestion of foodstuff in the mouth, the sympathetic neurons, in turn, transmit this message and the other digestive processes occur simultaneously. This action enhances the effects of the parasympathetic nerve cells. They complemented each other’s functions.

These are important types of dual innervations found in one organ in order for the body to function properly.