Autonomic Nervous System Receptors Quiz

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Questions and Answers

What is primarily responsible for voluntary control over skeletal muscles?

Autonomic nervous system

Parasympathetic nervous system

Somatic nervous system (correct)

Sympathetic nervous system

Which branch of the autonomic nervous system is associated with the 'rest and digest' response?

Parasympathetic nervous system (correct)

Sympathetic nervous system

Sensory nervous system

Somatic nervous system

How do sympathetic and parasympathetic nervous systems interact with organs and glands?

They have opposing functions where one can suppress the other. (correct)

They work independently without any overlap.

They have synergistic effects enhancing each other.

They exclusively control different organs without interaction.

Which function does the autonomic nervous system NOT control?

Skeletal muscle contraction Signup and view all the answers

What role do sensory neurons play in the nervous system?

Recognize changes in the environment Signup and view all the answers

What is the primary role of the central nervous system?

Process and integrate information about environmental changes Signup and view all the answers

Which of the following best describes acute stress?

A type of stress causing immediate physiological responses Signup and view all the answers

What physiological effects are associated with the sympathetic nervous system?

Fight or flight response activation Signup and view all the answers

How does chronic stress affect the body?

It may lead to cumulative physiological and psychological effects Signup and view all the answers

What are the three phases of stress response?

Alarm Stage, Resistance Stage, Exhaustion Stage Signup and view all the answers

Which part of the nervous system recognizes changes in the environment?

Peripheral Nervous System Signup and view all the answers

What role does Cortisol play in the stress response?

It regulates homeostasis during long-term stress Signup and view all the answers

Which statement accurately contrasts the functions of sensory and motor neurons?

Sensory neurons transmit information to the CNS, while motor neurons relay commands from the CNS to effectors Signup and view all the answers

What is the primary role of alpha-1 receptors in the sympathetic nervous system?

Constricts arterioles and dilates pupils Signup and view all the answers

Which effect is primarily promoted by muscarinic receptors in parasympathetic target tissues?

Constriction of bronchi Signup and view all the answers

What neurotransmitter primarily interacts with nicotinic receptors?

Acetylcholine Signup and view all the answers

How does the hypothalamus influence physiological responses related to emotions?

By linking emotional states to sympathetic nervous system responses Signup and view all the answers

What is the effect of beta-2 receptors in the sympathetic nervous system?

Dilation of bronchi and arterioles to skeletal muscles Signup and view all the answers

What effect do anxiolytics like benzodiazepines have on the hypothalamic-pituitary-adrenal axis?

Reduce activation of sympathetic nervous system Signup and view all the answers

Which receptor is responsible for increasing heart rate and force of contraction in the heart?

Beta-1 Signup and view all the answers

What effects are generally associated with the action of norepinephrine on alpha-2 receptors?

Constricts arterioles and decreases sympathetic tone Signup and view all the answers

How does the sympathetic nervous system affect the heart?

It increases heart rate and contractility. Signup and view all the answers

What is the effect of the parasympathetic nervous system on the salivary glands?

It increases secretion. Signup and view all the answers

Which of the following effects is NOT associated with the parasympathetic nervous system?

Increases urinary production. Signup and view all the answers

What role does the adrenal medulla play in sympathetic activation?

Increases epinephrine secretion. Signup and view all the answers

How does the sympathetic nervous system influence the pupil?

It dilates the pupil. Signup and view all the answers

Which statement best describes the effects of the autonomic nervous system on the lungs?

The sympathetic system dilates bronchi and increases respiratory rate. Signup and view all the answers

What effect does the parasympathetic nervous system have on the gastrointestinal system?

It increases motility and secretions. Signup and view all the answers

In terms of synaptic transmission, what initiates the signal in a neuron?

Pre-synaptic neuron. Signup and view all the answers

What is the role of cortisol during a stress response?

Promotes metabolism of glycogen to glucose Signup and view all the answers

Which of the following is a consequence of prolonged stress on the body?

Sustained elevation of blood pressure Signup and view all the answers

Which areas of the brain are particularly sensitive to cortisol?

Hippocampus and Prefrontal cortex Signup and view all the answers

What effect does prolonged cortisol secretion have on muscles?

Promotes breakdown of muscle proteins into amino acids Signup and view all the answers

During the stress response, what happens to the sympathetic nervous system?

It activates the fight or flight response Signup and view all the answers

How does cortisol affect the pancreas during stress?

Decreases insulin and increases glucagon Signup and view all the answers

What physical symptom may result from chronic stress affecting the digestive system?

Prolonged inhibition of digestive functions Signup and view all the answers

What may occur due to atrophy of the hippocampus from long-term stress?

Impairment in learning and memory Signup and view all the answers

What characterizes the somatic component of the motor system?

It is responsible for voluntary muscle movements Signup and view all the answers

Which effect is primarily associated with the sympathetic nervous system?

Enhanced respiratory rate Signup and view all the answers

How do the sympathetic and parasympathetic nervous systems facilitate homeostasis?

By opposing the functions to regulate organ activity Signup and view all the answers

What primarily activates the autonomic nervous system's components?

Receptors responding to environmental changes Signup and view all the answers

What function do motor neurons serve within the nervous system?

Responding to stimuli by transmitting signals to glands Signup and view all the answers

What is a primary method by which neurotransmitter action is terminated in the synaptic cleft?

Reuptake back into the presynaptic neuron Signup and view all the answers

Which neurotransmitter is associated with degradation by acetylcholinesterase in the synaptic cleft?

Acetylcholine Signup and view all the answers

What describes the primary consequence of chronic stress on the body?

It leads to cumulative physiological and psychological effects. Signup and view all the answers

Which phase of stress response is characterized by initial immediate reactions to a stressor?

Alarm Stage Signup and view all the answers

What effect do adrenergic receptors have in the autonomic nervous system?

Respond to epinephrine and norepinephrine Signup and view all the answers

What is the primary function of the central nervous system regarding environmental changes?

To process and integrate information. Signup and view all the answers

Which of the following describes a role of cholinergic receptors in the autonomic nervous system?

They promote both sympathetic and parasympathetic effects. Signup and view all the answers

What role does the peripheral nervous system play in response to environmental stimuli?

Recognizes changes and sends messages to the CNS. Signup and view all the answers

Which of the following actions is influenced by drugs targeting the autonomic nervous system?

They can prevent the destruction or reuptake of neurotransmitters. Signup and view all the answers

Which neurotransmitter is primarily involved in mediating the stress response through the autonomic nervous system?

Norepinephrine Signup and view all the answers

Which part of the stress response is most directly influenced by the hypothalamus-pituitary-adrenal axis?

Cortisol secretion Signup and view all the answers

What physiological change is primarily associated with the sympathetic nervous system during stress?

Increased heart rate and blood flow to muscles. Signup and view all the answers

What is a common result of prolonged exposure to stress hormones such as cortisol?

Atrophy of brain structures like the hippocampus. Signup and view all the answers

What effect does sympathetic stimulation have on the heart?

Increases heart rate and contractility Signup and view all the answers

Which of the following statements accurately describes parasympathetic influence on the gastrointestinal system?

Increases motility and secretions Signup and view all the answers

What is the primary effect of parasympathetic stimulation on the pupil?

Constricts the pupil Signup and view all the answers

How does the sympathetic nervous system affect the bronchi in the lungs?

Dilates bronchi and increases respiratory rate Signup and view all the answers

Which option represents the action of the autonomic nervous system on the urinary system during sympathetic activation?

Contracts bladder muscles, decreases urine production Signup and view all the answers

In what way does the autonomic nervous system influence the salivary glands under sympathetic conditions?

Decreases secretion of saliva Signup and view all the answers

What is the function of the adrenal medulla during sympathetic activation?

Increases secretion of epinephrine Signup and view all the answers

Which of the following best describes the role of synaptic transmission in neuron communication?

Pre-synaptic neuron initiates the signal Signup and view all the answers

What hormone is primarily secreted during the stress response to manage prolonged stress?

Cortisol Signup and view all the answers

Which physiological response is NOT a consequence of sustained cortisol elevation?

Enhanced immune response Signup and view all the answers

Which of the following actions does cortisol facilitate in the liver during a stress response?

Glycogen breakdown to glucose Signup and view all the answers

What role does the hypothalamus play in the stress response system?

It activates the HPA axis through the secretion of ACTH. Signup and view all the answers

Which brain regions are particularly sensitive to cortisol and are affected by long-term stress?

Hippocampus and Prefrontal Cortex Signup and view all the answers

What can result from chronic activation of the sympathetic nervous system?

Cardiovascular diseases Signup and view all the answers

What effect does cortisol have on muscle tissue during the stress response?

Stimulates protein breakdown Signup and view all the answers

How does chronic stress affect the endocrine function of the pancreas?

Increases glucagon and decreases insulin Signup and view all the answers

Study Notes

Autonomic Nervous System Receptors

Acetylcholine (Ach):
- Nicotinic Receptors: Found on postganglionic neurons in both the sympathetic and parasympathetic nervous systems. Exhibit a mix of sympathetic and parasympathetic effects.
- Muscarinic Receptors: Found on target tissues in the parasympathetic nervous system. Promote parasympathetic effects.
Norepinephrine (NE):
- Alpha-1 receptors: Found on target tissues in the sympathetic nervous system. Effects include constricting arterioles and dilating pupils.
- Alpha-2 receptors: Found on target tissues in the sympathetic nervous system. Decrease the tone of the sympathetic nervous system.
- Beta-1 receptors: Found on target tissues in the sympathetic nervous system. Effects include increasing heart rate and the force of contraction of the heart.
- Beta-2 receptors: Found on target tissues in the sympathetic nervous system. Effects include dilating bronchi and dilating arterioles to skeletal muscles.

Overview of Nervous System Regulation

Higher brain centers, particularly the hypothalamus, can link emotional states from the limbic system to physiological responses.
Anxiolytics (e.g., benzodiazepines) can indirectly modulate activity of the hypothalamic-pituitary-adrenal (HPA) axis, reducing sympathetic nervous system activation.

Central vs. Peripheral Nervous System

Central Nervous System (CNS): Consists of the brain and spinal cord. Processes and integrates information about environmental changes, receives and processes information from the peripheral nervous system (PNS), and plans and initiates responses or actions.
Peripheral Nervous System (PNS): Consists of cranial nerves and spinal nerves. Recognizes and relays changes in the internal and external environment. Composed of sensory neurons (messages to the CNS) and motor neurons (messages from the CNS to carry out responses).
- Motor neurons can be further divided into somatic (voluntary control over skeletal muscles) and autonomic (involuntary control over vital functions).

Sensory and Motor Neurons

Sensory Neurons: Specialized receptors and nerves recognize changes in the environment and convert them into signals the CNS can understand. Examples include touch, pain, heat, body position, light, sound, and the composition of body fluids.
Motor Neurons: Respond to changes by contracting muscles or secreting chemicals.

Autonomic Nervous System

Composed of the sympathetic (fight or flight) and parasympathetic (rest and digest) nervous systems.
Most organs and glands receive input from both branches of the ANS, which have opposing functions. The activity of organs/glands depends on which branch's signal is more active.
Homeostasis is achieved by changing the tone of one or both branches of the ANS, which is altered by increasing or decreasing the firing of sympathetic/parasympathetic nerves.

Effects of the Autonomic Nervous System

Sympathetic: Increases alertness (brain), dilates pupils, decreases salivary gland secretion, increases heart rate and contractility, dilates bronchi and increases respiratory rate, decreases GI motility and secretions, increases pancreas release of glucagon, increases epinephrine secretion from the adrenal medulla, relaxes bladder muscles and decreases urine production, and inhibits sex organ activity.
Parasympathetic: Constrict pupils, increases salivary gland secretion, decreases heart rate, constricts bronchi and decreases respiratory rate, increases GI motility and secretions, increases pancreas secretion of insulin, contracts bladder muscles and increases urine production, and stimulates sex organ activity.

Synaptic Transmission

Neurons communicate through synapses.
Pre-synaptic neuron initiates a signal that is received by the post-synaptic neuron.

Stress Response

Alarm Reaction: Activation of the sympathetic nervous system (fight or flight) in response to a stressor. Leads to the release of norepinephrine and epinephrine from the adrenal medulla, resulting in increased sympathetic NS functions and a decrease in parasympathetic innervation.
Resistance/Adaptation: Persistent stress activates the hypothalamic-pituitary-adrenal (HPA) axis, which promotes the secretion of adrenocorticotropic hormone (ACTH) by the pituitary gland. ACTH stimulates the adrenal cortex to make cortisol. Cortisol helps deal with long-term stress by increasing blood sugar, enhancing metabolism, and suppressing non-essential functions.
Exhaustion: Sustained elevation of blood pressure and heart rate can lead to cardiovascular diseases. Prolonged inhibition of digestive and urinary functions can lead to gastrointestinal and renal disorders. Chronic stress weakens the immune system, leading to decreased muscle mass and fat, resulting in weight loss.

Cortisol

Known as the "stress hormone".
Helps the body deal with stress by increasing energy supply.
- Promotes metabolism of glycogen to glucose in the liver.
- Reduces glucose uptake/consumption in muscle and promotes breakdown of muscle proteins into amino acids for energy production.
- Promotes lipid breakdown for additional energy in fat cells.
- Decreases insulin and increases glucagon to increase blood glucose in the pancreas.
Increases blood pressure by promoting vasoconstriction.
Reduces inflammation and suppresses the immune system.

Behavioral and Emotional Responses to Stress

Hippocampus and prefrontal cortex are the two areas of the brain with the most glucocorticoid receptors and are highly sensitive to cortisol. Both areas atrophy with long-term stress.
Hippocampus: Associated with learning and memory.

### Stress and Coping

Stress is any physical or psychological stimulus that disrupts homeostasis.
Acute stress is caused by immediate stressors and is adaptive.
Chronic stress is caused by persistent stressors and is maladaptive.

### Central Nervous System

Consists of the brain and spinal cord.
Processes and integrates information about environmental changes.
Receives and processes information from the peripheral nervous system (PNS).
Plans and initiates responses or actions.

Peripheral Nervous System

Consists of cranial nerves and spinal nerves
Recognizes changes in the internal and external environments.
Sensory neurons carry messages to the central nervous system (CNS).
Motor neurons carry messages from the CNS to carry out responses.
Somatic Nervous System: Voluntary control over skeletal muscles.
Autonomic Nervous System: Involuntary control over vital functions such as cardiovascular, digestive, respiratory, and genitourinary systems.

Autonomic Nervous System

Consists of the sympathetic and parasympathetic nervous systems.
Sympathetic Nervous System: "Fight or Flight" response
Parasympathetic Nervous System: "Rest and Digest" response
Most organs and glands receive input from both branches of the ANS.
The activity of organs/glands depends on which branch's signal is more active.
Tone can be altered by increasing or decreasing the firing of sympathetic/parasympathetic nerves.

Effects of the Autonomic Nervous System

Brain: Increases alertness.
Pupil: Dilates (sympathetic) or constricts (parasympathetic).
Salivary Glands: Decreases secretion (sympathetic) or increases secretion (parasympathetic).
Heart: Increases heart rate and contractility (sympathetic) or decreases heart rate (parasympathetic).
Lungs: Dilates bronchi, increases respiratory rate (sympathetic) or constricts bronchi, decreases respiratory rate (parasympathetic).
Gastrointestinal System: Decreases motility and secretion (sympathetic) or increases motility and secretion (parasympathetic).
Pancreas: Increases release of glucagon (sympathetic) or increases secretion of insulin (parasympathetic).
Adrenal Medulla: Increases epinephrine secretion (sympathetic).
Urinary System: Relaxes bladder muscles, decreases urine production (sympathetic) or contracts bladder muscles, increases urine production (parasympathetic).
Sex Organs: Inhibits (sympathetic) or stimulates (parasympathetic).
Integumentary System: Increases perspiration (sympathetic).

Synaptic Transmission

Neurons communicate through synapses.
Presynaptic neurons initiate signals received by postsynaptic neurons.
Presynaptic neurons contain neurotransmitters stored in vesicles.
Neurotransmitters are released into the synaptic cleft when stimulated by an action potential.
Neurotransmitters bind to receptors on postsynaptic neurons or target tissues at the neuroeffector junction.
Binding induces a response, either activating or inhibiting the action potential.

Neurotransmitters

Over 50 neurotransmitters in the body!
Norepinephrine and acetylcholine are the main neurotransmitters of the autonomic nervous system.

Termination of Neurotransmitter Action

Neurotransmitters separate from receptors, returning them to baseline activity.
Neurotransmitters are removed from the synapse through:
- Reuptake back into the presynaptic neuron.
- Degradation in the synaptic cleft by enzymes:
  - Acetylcholine is degraded by acetylcholinesterase (AchE).
  - Norepinephrine is degraded by monoamine oxidase (MAO) or catechol-o-methyl transferase (COMT) in the synapse.

Autonomic Nervous System Drugs

Alter neurotransmitter synthesis in the preganglionic nerve.
Prevent neurotransmitter storage in vesicles within the preganglionic nerve.
Influence neurotransmitter release from the preganglionic nerve.
Bind to neurotransmitter receptor sites on the postganglionic nerve.
Prevent the normal destruction or reuptake of neurotransmitters.

ANS Receptors

Cholinergic Receptors: Respond to acetylcholine.
- Nicotinic: Found on postganglionic neurons in the ANS. Promote sympathetic and parasympathetic effects.
- Muscarinic: Found at the neuromuscular junction of skeletal muscle cells.
Adrenergic Receptors: Responds to epinephrine and norepinephrine.

Stress Response

Alarm Reaction: Stressor activates the sympathetic nervous system (SNS) (fight or flight).
- SNS releases norepinephrine and epinephrine from the adrenal medulla.
- Increased sympathetic NS functions and decreased parasympathetic innervation.
Resistance/Adaptation: Persistent stress activates the hypothalamic-pituitary-adrenal (HPA) axis, which promotes the secretion of adrenocorticotropic hormone (ACTH).
- ACTH stimulates the adrenal cortex to produce cortisol.
- Cortisol helps the body deal with long-term stress by increasing blood sugar, enhancing metabolism, and suppressing non-essential functions like digestion and immune response.
Exhaustion:
- The HPA axis can become dysregulated.
- Sustained elevation of blood pressure and heart rate can lead to cardiovascular diseases.
- Prolonged inhibition of digestive and urinary functions can lead to gastrointestinal and renal disorders.
- Chronic stress weakens the immune system.
- Leads to decreased muscle mass and fat, resulting in weight loss.

Cortisol

"Stress hormone"
Helps the body deal with stress by increasing energy supply.
Liver: Promotes metabolism of glycogen to glucose.
Muscle: Reduces glucose uptake/consumption and promotes the breakdown of muscle proteins into amino acids for energy production.
Fat cells: Promote lipid breakdown for additional energy.
Pancreas: Decreases insulin and increases glucagon to increase blood glucose.
Other effects:
- Increases blood pressure by promoting vasoconstriction.
- Reduces inflammation and suppresses the immune system.

Behavioral and Emotional Responses to Stress

The hippocampus and prefrontal cortex are the two areas of the brain with the most glucocorticoid receptors, making them highly sensitive to cortisol.
Both areas atrophy with long-term stress.
Hippocampus: Associated with learning and memory.

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Description

Test your knowledge on the receptors of the autonomic nervous system, focusing on acetylcholine and norepinephrine. This quiz covers the functions and locations of nicotinic, muscarinic, and adrenergic receptors. Perfect for students of physiology or anyone interested in understanding how our nervous system operates.