The involuntary nervous system is a vital component of human physiology, providing essential functions to maintain physiological homeostasis. The involuntary nervous system consists of two distinct branches: the autonomic nervous system and the enteric nervous system. In this article, we review our current understanding of the anatomy, physiology, and pharmacology of these two branches of the involuntary nervous system.
The autonomic nervous system is responsible for maintaining essential functions such as heart rate, blood pressure, digestion, and respiration. It is composed of two distinct branches: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is responsible for activating the “fight or flight” response, while the parasympathetic nervous system is responsible for activating the “rest and digest” response. The sympathetic and parasympathetic nervous systems are regulated by neurotransmitters such as epinephrine, norepinephrine, acetylcholine, and serotonin.
The enteric nervous system is responsible for controlling the digestive system. It is composed of two networks of neurons: the myenteric plexus and the submucosal plexus. These two networks are responsible for controlling the propulsion and absorption of food, as well as regulating the secretion of digestive enzymes. The enteric nervous system is regulated by neurotransmitters such as acetylcholine, serotonin, and dopamine.
Both the autonomic and enteric nervous systems are regulated by hormones and neurotransmitters. Hormonal regulation of the autonomic nervous system is accomplished through the hypothalamus, pituitary, and adrenal glands. Neurotransmitters such as acetylcholine, epinephrine, norepinephrine, serotonin, and dopamine are responsible for modulating the activity of the autonomic and enteric nervous systems.
The pharmacology of the involuntary nervous system is an area of active research. Several drugs have been developed to target specific neurotransmitters or hormones in order to modulate the activity of the autonomic and enteric nervous systems. These drugs include anticholinergics, beta blockers, cholinesterase inhibitors, and serotonin reuptake inhibitors.
In conclusion, the involuntary nervous system is an essential component of human physiology. It is composed of the autonomic nervous system and the enteric nervous system, both of which are regulated by hormones and neurotransmitters. The pharmacology of the involuntary nervous system is an area of active research, and several drugs have been developed to modulate its activity.
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