2-Minute Neuroscience: Parasympathetic Nervous System

Neuroscientifically Challenged

22 Feb 202002:00

Summary

TLDRThe parasympathetic nervous system, part of the autonomic nervous system, is crucial for energy conservation and processes like digestion. Originating from the brainstem and sacral spinal cord, its preganglionic neurons synapse with postganglionic neurons in ganglia near target organs, primarily releasing acetylcholine. It's often called the 'rest and digest' system, but this term simplifies its complex functions.

Takeaways

🧠 The parasympathetic nervous system is part of the autonomic nervous system, controlling automatic processes like digestion and heart rate.
🌿 It is often called the 'rest and digest' system due to its role in energy conservation and waste elimination.
🔍 The system is an oversimplification and does not fully capture the range of activities of the parasympathetic nervous system.
📍 Nerves of the parasympathetic system originate in the brainstem and the sacral spinal cord.
🌐 These nerves extend to ganglia, clusters of neurons, before reaching their target organs.
🔬 Parasympathetic ganglia are typically located near or within the organs they serve.
🛤️ Preganglionic neurons from the brainstem and spinal cord synapse with postganglionic neurons in the ganglia.
🚀 Postganglionic neurons then extend to the targets of the parasympathetic nervous system.
💊 The primary neurotransmitter released by the parasympathetic system is acetylcholine.
🧠🔌 Preganglionic neurons from the brainstem are associated with cranial nerves that innervate the head, neck, and internal organs.
🌐📍 Preganglionic neurons from the sacral spinal cord form pelvic nerves, supplying the organs of the pelvis.

Q & A

What is the parasympathetic nervous system?
-The parasympathetic nervous system is a subdivision of the autonomic nervous system, which controls automatic processes in the body such as digestion, heart rate, and respiration.
What is the role of the parasympathetic nervous system in the body?
-The parasympathetic nervous system is typically associated with energy conservation and processes like digestion and elimination of waste products from the body.
Why is the parasympathetic nervous system sometimes called the 'rest and digest' system?
-It is called the 'rest and digest' system because of its association with energy conservation and its role in digestion and waste elimination, although this term is an oversimplification and does not accurately describe its full range of activities.
Where do the nerves of the parasympathetic nervous system originate?
-The nerves of the parasympathetic nervous system originate in the brainstem and the sacral spinal cord.
What is the function of ganglia in the parasympathetic nervous system?
-Ganglia are clusters of neurons that the parasympathetic neurons extend to first before reaching their targets. The parasympathetic ganglia are typically found near or in the wall of the organs they supply.
What are preganglionic and postganglionic neurons?
-Preganglionic neurons are those that travel from the brainstem and spinal cord to the parasympathetic ganglia, where they synapse with postganglionic neurons. Postganglionic neurons then extend to the targets of the parasympathetic nervous system.
Which neurotransmitter do the preganglionic and postganglionic neurons of the parasympathetic nervous system primarily release?
-The preganglionic and postganglionic neurons of the parasympathetic nervous system primarily release the neurotransmitter acetylcholine.
Which cranial nerve nuclei give rise to preganglionic neurons in the brainstem?
-The preganglionic neurons in the brainstem arise from the cranial nerve nuclei for the oculomotor, facial, glossopharyngeal, and vagus nerves.
What is the role of the vagus nerve in the parasympathetic nervous system?
-The fibers that travel with the vagus nerve provide parasympathetic innervation to the head and neck, and also supply the internal organs of the thorax and abdomen.
What are the pelvic nerves and what do they supply?
-The pelvic nerves are formed by preganglionic neurons that originate in the sacral spinal cord, and they supply the organs of the pelvis.
How do the parasympathetic preganglionic neurons that originate in the sacral spinal cord differ from those in the brainstem?
-The preganglionic neurons originating in the sacral spinal cord come together to form the pelvic nerves, which specifically supply the organs of the pelvis, unlike those in the brainstem that supply the head, neck, thorax, and abdomen.

Outlines

00:00

🌿 Parasympathetic Nervous System Overview

The first paragraph introduces the parasympathetic nervous system as a key part of the autonomic nervous system, which oversees automatic bodily functions such as digestion, heart rate, and respiration. It is linked to energy conservation and waste elimination, earning it the nickname 'rest and digest' system, though this is a simplification. The nerves originate from the brainstem and sacral spinal cord, synapsing in ganglia near the organs they serve. The neurotransmitter acetylcholine is predominantly released, with preganglionic neurons from the brainstem associated with specific cranial nerves, extending to various body regions including the head, neck, thorax, and abdomen, while those from the sacral spinal cord form pelvic nerves for the pelvic organs.

Mindmap

Keywords

💡Parasympathetic Nervous System

The parasympathetic nervous system is a key component of the autonomic nervous system, which is responsible for involuntary bodily functions. It is associated with energy conservation and processes such as digestion and waste elimination, earning it the nickname 'rest and digest' system. This system is integral to the video's theme as it outlines the functions and importance of the parasympathetic nervous system in maintaining homeostasis.

💡Autonomic Nervous System

The autonomic nervous system is a division of the peripheral nervous system that controls automatic processes in the body without conscious effort. It includes the parasympathetic and sympathetic nervous systems, which work in tandem to regulate bodily functions. The video emphasizes the role of the autonomic nervous system in maintaining life-sustaining processes such as heart rate and respiration.

💡Peripheral Nervous System

The peripheral nervous system consists of all the neural elements outside the brain and spinal cord. It is responsible for transmitting information between the central nervous system and the rest of the body. In the context of the video, the peripheral nervous system is the broader category under which the parasympathetic nervous system operates, highlighting its role in connecting the brain's commands to the body's functions.

💡Energy Conservation

Energy conservation refers to the process by which the body efficiently uses and preserves its energy resources. The parasympathetic nervous system is linked to this concept as it promotes activities that conserve energy, such as digestion, which is a key focus of the video. The script mentions that the parasympathetic system is associated with energy conservation, emphasizing its role in resting states.

💡Digestion

Digestion is the process by which food is broken down in the body to be absorbed and utilized for energy. The video script highlights digestion as a primary function of the parasympathetic nervous system, illustrating how this system supports the body's restorative processes during periods of inactivity or relaxation.

💡Elimination

Elimination refers to the process of expelling waste products from the body. The parasympathetic nervous system aids in this process by promoting the efficient removal of waste, as mentioned in the script. This function is part of the system's broader role in maintaining the body's internal balance.

💡Brainstem

The brainstem is a part of the brain that connects to the spinal cord and is responsible for many automatic functions, including breathing and heart rate. In the video, the brainstem is identified as the origin of some parasympathetic preganglionic neurons, which are crucial for the activation of the parasympathetic nervous system.

💡Sacral Spinal Cord

The sacral spinal cord is the lower part of the spinal cord that gives rise to nerves responsible for various bodily functions, including those related to the parasympathetic nervous system. The script specifies that the sacral spinal cord is the origin for preganglionic neurons that form the pelvic nerves, which supply the organs of the pelvis.

💡Ganglia

Ganglia are clusters of neurons located outside the central nervous system. In the context of the parasympathetic nervous system, ganglia serve as relay points where preganglionic neurons synapse with postganglionic neurons. The video script describes the parasympathetic ganglia as being typically found near or within the organs they serve.

💡Preganglionic Neurons

Preganglionic neurons are the nerve cells that originate in the brainstem or sacral spinal cord and extend to the ganglia. They are essential for the parasympathetic nervous system, as they synapse with postganglionic neurons within the ganglia. The video script explains that these neurons release the neurotransmitter acetylcholine, which is crucial for the system's function.

💡Postganglionic Neurons

Postganglionic neurons are the nerve cells that synapse with preganglionic neurons in the ganglia and then extend to the target organs of the parasympathetic nervous system. They are vital for transmitting the signals from the ganglia to effect the actions of the parasympathetic system, as described in the video script.

💡Acetylcholine

Acetylcholine is a neurotransmitter that plays a significant role in the parasympathetic nervous system. It is released by both preganglionic and postganglionic neurons, facilitating the communication necessary for the system's functions. The video script mentions acetylcholine as the primary neurotransmitter of the parasympathetic nervous system, linking it to the system's restorative and energy-conserving activities.

Highlights

The parasympathetic nervous system is a subdivision of the autonomic nervous system controlling automatic processes like digestion, heart rate, and respiration.

It is associated with energy conservation and processes such as digestion and waste elimination, often referred to as the 'rest and digest' system.

The term 'rest and digest' is an oversimplification and does not fully describe the range of activities of the parasympathetic nervous system.

Nerves of the parasympathetic nervous system originate in the brainstem and sacral spinal cord.

Parasympathetic ganglia, where preganglionic neurons synapse with postganglionic neurons, are typically found near the organs they supply.

Preganglionic neurons from the brainstem synapse with postganglionic neurons in the ganglia before extending to their targets.

The parasympathetic nervous system primarily releases the neurotransmitter acetylcholine through its preganglionic and postganglionic neurons.

Preganglionic neurons originating in the brainstem arise from the cranial nerve nuclei for oculomotor, facial, glossopharyngeal, and vagus nerves.

Cranial nerve fibers provide parasympathetic innervation to the head, neck, and internal organs of the thorax and abdomen via the vagus nerve.

Preganglionic neurons from the sacral spinal cord form the pelvic nerves, supplying the organs of the pelvis.

The parasympathetic nervous system is integral to the body's automatic functioning, impacting digestion, heart rate, and respiration.

Understanding the parasympathetic nervous system is crucial for insights into bodily processes and energy conservation.

The anatomical origins and pathways of the parasympathetic nervous system are key to its function and impact on the body.

The neurotransmitter acetylcholine plays a central role in the communication within the parasympathetic nervous system.

The brainstem and sacral spinal cord are the primary sources of the parasympathetic nervous system's preganglionic neurons.

The distribution of parasympathetic ganglia near the organs they innervate optimizes the efficiency of the nervous system.

The parasympathetic nervous system's role in 'rest and digest' activities is vital for maintaining homeostasis and overall health.

The cranial and sacral origins of the parasympathetic nervous system highlight its extensive reach throughout the body.