W1 L6 ANS anatomy

Sympathetic Nervous System (SNS)

Prepares the body for stress responses, increasing alertness and physical performance (fight-or-flight response).

Parasympathetic Nervous System (PNS)

Promotes relaxation and energy conservation, decreasing heart rate and enhancing digestion.

Enteric Nervous System (ENS)

Manages complex digestive processes autonomously; often referred to as the 'second brain'.

Autonomic Nervous System (ANS)

Regulates involuntary bodily functions and works in conjunction with the endocrine system to maintain homeostasis.

Cholinergic Agonists

Pharmacological agents that stimulate acetylcholine receptors, enhancing parasympathetic activity.

Adrenergic Antagonists

Pharmaceuticals that block norepinephrine receptors, reducing sympathetic responses.

Fight-or-Flight Response

Physiological response activated by the SNS that prepares the body for immediate physical action.

Neurotransmittters in the ANS

Includes acetylcholine (PNS) and noradrenaline (SNS), which mediate responses in their respective systems.

Functions of the PNS

Slows heart rate, reduces blood pressure, stimulates digestion, and helps regulate sexual arousal.

Functions of the SNS

Increases heart rate, facilitates bronchodilation, and reduces digestive activity.

Hypothalamus Role in ANS

Integrates sensory information and coordinates autonomic and hormonal responses, regulating homeostasis.

What is the primary function of the SNS?

To prepare the body for stress, enhancing alertness and physical performance through fight-or-flight mechanisms.

How does the PNS support energy conservation?

By decreasing heart rate, lowering blood pressure, and stimulating digestion.

What are the two main divisions of the Autonomic Nervous System?

The Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PNS).

What neurotransmitter is primarily associated with the Parasympathetic nervous system?

Acetylcholine.

What is the 'second brain'?

The Enteric Nervous System (ENS), which controls digestive processes independently.

Explain how the Autonomic Nervous System contributes to homeostasis during a state of stress.

The Autonomic Nervous System (ANS) adjusts bodily functions to maintain homeostasis during stress by activating the Sympathetic Nervous System (SNS) for immediate responses like increased heart rate and reduced digestive activity, while the Parasympathetic Nervous System (PNS) helps to restore balance post-stress by promoting relaxation and digestion.

Describe the role of the hypothalamus in integrating autonomic responses.

The hypothalamus acts as a control center by processing sensory information and coordinating both autonomic and hormonal responses to regulate various homeostatic functions, such as temperature, hunger, and stress responses.

Differentiate between cholinergic and adrenergic antagonists in their mechanisms of action within the ANS.

Cholinergic antagonists block acetylcholine receptors, thereby inhibiting parasympathetic activity, while adrenergic antagonists block norepinephrine receptors, reducing sympathetic responses and effects on the body.

Discuss the physiological implications of an overactive sympathetic nervous system.

An overactive SNS can lead to chronic stress responses, resulting in elevated heart rate, increased blood pressure, anxiety disorders, and digestive issues due to prolonged inhibition of the PNS, which may harm overall health.

How do neurotransmitters differ in their functions within the SNS and PNS?

Acetylcholine primarily facilitates 'rest and digest' functions in the PNS, enhancing bodily restoration, while noradrenaline drives 'fight-or-flight' responses in the SNS, promoting increased alertness and physical readiness.

Homeostasis

The process by which biological systems maintain stability while adjusting to conditions that are optimal for survival.

Stress Response

A series of physiological changes initiated by the body in reaction to stressors, primarily regulated by the Sympathetic Nervous System.

Neurotransmitter

Chemical substances that transmit signals across a synapse between neurons, playing critical roles in signaling within the nervous system.

Autonomic Reflexes

Involuntary responses that occur when the ANS automatically regulates body functions without conscious control, such as heart rate and digestion.

Sympathetic Activation

The process by which the sympathetic nervous system increases alertness and energy use, often leading to heightened heart rate, blood pressure, and energy release.

Parasympathetic Activation

The process by which the parasympathetic nervous system promotes a state of calm, reducing heart rate, increasing gastrointestinal activity, and conserving energy.

Dual Innervation

The phenomenon where most organs receive input from both the sympathetic and parasympathetic divisions, allowing for fine-tuned physiological responses.

Adrenal Medulla

The inner part of the adrenal glands that releases adrenaline and norepinephrine into the bloodstream during stress responses, supplementing SNS activity.

Relaxation Response

The physiological state of rest induced by the Parasympathetic Nervous System that counteracts the stress response, lowering heart rate and promoting digestion.

Visceral Nerves

Nerves that transmit sensory information from internal organs to the CNS, playing a key role in the ANS in regulating bodily functions.

Acetylcholine Receptors

Protein molecules in cell membranes that respond to the neurotransmitter acetylcholine, crucial for parasympathetic signaling.

Noradrenaline Receptors

Protein molecules that bind to noradrenaline, primarily involved in the sympathetic nervous system functions.

Prefrontal Cortex Role

Part of the brain responsible for decision-making and moderating social behavior, which interacts with the autonomic nervous system in stress regulation.

Impact of Stress on Digestion

Chronic activation of the sympathetic nervous system can lead to inhibited digestive function, causing gastrointestinal problems.

Emotional Responses and ANS

The autonomic nervous system can be influenced by emotional states, modulating physiological responses such as heart rate and blood pressure.

Chronic Stress Effects

Long-term activation of the stress response can lead to health issues, such as cardiovascular disease, metabolic syndrome, and weakened immune function.

Role of the Amygdala

A brain structure involved in processing emotions; it plays a key role in triggering the stress response and autonomic nervous system activation.

Feedback Mechanisms in ANS

Processes by which the body maintains stability by self-regulating, often involving sensory feedback to adjust autonomic output

How does the amygdala interact with the autonomic nervous system during stress responses?

The amygdala processes emotional stimuli and signals the hypothalamus to initiate the stress response through the sympathetic nervous system, leading to physiological changes like increased heart rate and blood pressure.

Describe the phenomenon of 'rebound effect' in the context of the parasympathetic nervous system.

The rebound effect refers to the overshoot in parasympathetic activity after a period of high sympathetic activation, resulting in physiological responses such as bradycardia and enhanced digestive processes.

What is the role of baroreceptors in autonomic regulation of blood pressure?

Baroreceptors are stretch-sensitive receptors located in blood vessels that detect changes in blood pressure and relay this information to the central nervous system, which adjusts autonomic output to maintain homeostasis.

Explain the effects of chronic sympathetic nervous system activation on immune function.

Chronic activation of the sympathetic nervous system can lead to immunosuppression by increasing cortisol levels, which may inhibit inflammatory responses and result in a higher susceptibility to infections and illness.

Discuss the concept of neuroplasticity and its relevance to the autonomic nervous system.

Neuroplasticity refers to the brain's ability to reorganize itself by forming new neural connections; this is relevant to the ANS as it adapts and changes in response to chronic stress, impacting the regulation of autonomic functions.

What are the implications of functional connectivity between the brain and the autonomic nervous system?

Functional connectivity refers to the mutual influence of brain regions on autonomic function, suggesting that psychological states (like stress) can impact physiological responses through pathways such as the prefrontal cortex's regulation of the hypothalamus and autonomic output.

Define the role of the insula in the integration of emotional and physiological responses within the ANS.

The insula functions as a hub for interoceptive awareness, integrating sensory information about the body's internal state and emotional processing, influencing autonomic responses by modulating activity in the sympathetic and parasympathetic pathways.

How does the concept of 'allostasis' differ from 'homeostasis' in the context of the ANS?

Allostasis refers to the process of achieving stability through change by adapting to stressors over time, while homeostasis maintains internal balance in a stable environment, indicating that the ANS must constantly adjust its output to meet varying demands.

Differentiate between tonic and phasic activity of the autonomic nervous system.

Tonic activity refers to the baseline level of autonomic activation maintaining homeostasis,

while phasic activity involves transient changes in autonomic tone in response to external stimuli or stressors, reflecting dynamic adjustments of the ANS.

Explain the significance of the vagus nerve in the regulation of parasympathetic activity.

The vagus nerve is the primary component of the parasympathetic nervous system, responsible for conveying signals that regulate heart rate, gastrointestinal peristalsis, and other functions, playing a critical role in promoting relaxation and counteracting stress responses