Autonomic Nervous System Overview

The autonomic nervous system (ANS) is a control system that acts largely unconsciously and regulates bodily functions such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.

The sympathetic nervous system is responsible for the "fight-or-flight" response. It prepares the body for stressful situations by increasing heart rate, blood pressure, and respiration.

The parasympathetic nervous system is responsible for the "rest-and-digest" response. It promotes calming and relaxation.

The ANS operates through specialized nerves and ganglia. Ganglia are clusters of nerve cell bodies outside the central nervous system. Each division of the ANS has its specific ganglia and receptors.

The sympathetic nervous system uses norepinephrine as its neurotransmitter, while the parasympathetic nervous system uses acetylcholine. These neurotransmitters interact with specific receptors on target organs to produce their effects.

Sympathetic preganglionic neurons travel through the anterior spinal nerves and white rami communicantes to reach the paravertebral ganglia.

After reaching a paravertebral ganglion, a sympathetic preganglionic neuron can either synapse there or ascend to a higher ganglion.

A sympathetic preganglionic neuron can also bypass the paravertebral ganglia and travel directly to a prevertebral ganglion.

The sympathetic nervous system is responsible for the 'fight-or-flight' response, preparing the body for stressful situations.

The parasympathetic nervous system is responsible for the 'rest-and-digest' response, promoting relaxation and energy conservation.

The sympathetic nervous system increases heart rate, blood pressure, and respiration to prepare the body for action.

The parasympathetic nervous system slows heart rate and breathing, and promotes digestion and waste elimination.

The autonomic nervous system carries limited sensory information from internal organs to the central nervous system.

A division of the autonomic nervous system that controls involuntary bodily functions, such as digestion, heart rate, and breathing. It's known for promoting 'rest and digest' responses.

A division of the autonomic nervous system that controls involuntary bodily functions, such as increasing heart rate, dilating pupils, and sweating. It's known for promoting 'fight-or-flight' responses.

Neurons that carry signals from the central nervous system (brain and spinal cord) to the autonomic ganglia.

Neurons that carry signals from the autonomic ganglia to the target organs.

Clusters of nerve cell bodies located outside the central nervous system, where preganglionic and postganglionic neurons synapse.

The chemical messenger released at all autonomic ganglia by preganglionic fibres.

A type of receptor found on autonomic ganglia, which binds acetylcholine and allows the signal to pass.

A type of receptor found on target organs of the parasympathetic nervous system, which binds acetylcholine and produces its specific effects.

The neurotransmitter released by most postganglionic sympathetic fibres.

The sympathetic nervous system's outflow originates from the thoracic and lumbar regions of the spinal cord, from T1 to L2/3.

Norepinephrine is the primary neurotransmitter of the sympathetic nervous system. It is released from nerve endings and interacts with various receptors.

The primary way norepinephrine is removed from the synapse is through reuptake into the presynaptic nerve terminal. This process efficiently recycles norepinephrine.

Norepinephrine binds to various adrenergic receptors. Alpha 1, Beta 1, and Beta 2 receptors are key examples. They trigger different cellular responses.

Adrenaline, also known as epinephrine, is another important hormone in the sympathetic nervous system. It's primarily removed from the bloodstream by the liver and kidneys.

Acetylcholine is the main neurotransmitter of the parasympathetic nervous system. It is responsible for 'rest and digest' actions.

Adrenaline and noradrenaline, also known as epinephrine and norepinephrine respectively, are hormones and neurotransmitters primarily produced in the adrenal medulla, located on top of the kidneys. They are synthesized from the amino acid tyrosine.

Adrenaline and noradrenaline are released into the bloodstream by the adrenal medulla in response to stress, excitement, or physical activity. They are then transported throughout the body, where they bind to specific receptors on target cells.

Adrenaline and noradrenaline are deactivated by enzymes in the liver and other tissues. They can also be taken up by nerve cells and recycled.

Adrenaline and noradrenaline bind to specific receptors on target cells, primarily belonging to the adrenergic receptor family. These receptors are categorized into α and β subtypes, each triggering different responses in different tissues.

Adrenaline and noradrenaline primarily act on the sympathetic nervous system, increasing heart rate, blood pressure, blood sugar, and respiration. This is known as the 'fight or flight' response, preparing the body for immediate action.

Adrenaline and noradrenaline can cause effects like tremors, anxiety, sweating, and increased alertness. These are typical responses during times of stress.

Adrenaline plays a significant role in regulating blood pressure, heart rate, and breathing. It is also involved in glucose metabolism and the stress response.

Noradrenaline is primarily a neurotransmitter, involved in regulating mood, attention, and sleep. It also has some direct effects on the cardiovascular system.

A type of neurotransmitter that plays a crucial role in the sympathetic nervous system's "fight-or-flight" response.

A chemical compound that forms the core structure of catecholamines.

The rate-limiting step in the synthesis of catecholamines, meaning it controls the overall production speed.

A precursor to both adrenaline and noradrenaline, acting as an intermediary in their synthesis.

An enzyme essential for the conversion of dopamine into noradrenaline, relying on the health of the adrenal cortex.

The process of converting noradrenaline into adrenaline, involving the enzyme PNMT.

Hormones produced by the adrenal medulla, playing a vital role in the "fight-or-flight" response.

The central part of the adrenal gland responsible for producing catecholamines.

The outer layer of the adrenal gland responsible for producing other hormones like cortisol.

Specialized cells in the adrenal medulla that release adrenaline and noradrenaline.

The process of the body's automatic response to stress, triggered by catecholamines.

Cell surface receptors that bind to catecholamines, triggering a cascade of reactions within the cell.

A type of adrenergic receptor found in various locations including blood vessels and the gastrointestinal system, responsible for vasoconstriction and other metabolic effects.

A type of adrenergic receptor found in the heart, responsible for increasing heart rate, contractility, and conduction

A type of adrenergic receptor found in the lungs, vascular system, and other tissues, responsible for relaxing smooth muscles and promoting other metabolic effects.

A type of adrenergic receptor that is not covered in this lesson, but related to other physiological processes.