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Questions and Answers
During which activity is there an increase in output of the parasympathetic division?
During which activity is there an increase in output of the parasympathetic division?
Which function is primarily associated with the parasympathetic division of the autonomic nervous system?
Which function is primarily associated with the parasympathetic division of the autonomic nervous system?
How does the enteric nervous system primarily interact with other divisions of the autonomic nervous system?
How does the enteric nervous system primarily interact with other divisions of the autonomic nervous system?
What is a primary role of the sympathetic nervous system compared to the parasympathetic division?
What is a primary role of the sympathetic nervous system compared to the parasympathetic division?
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Which of the following is NOT a condition under which the parasympathetic division increases its output?
Which of the following is NOT a condition under which the parasympathetic division increases its output?
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What is a primary function of the autonomic nervous system?
What is a primary function of the autonomic nervous system?
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Which division of the autonomic nervous system is primarily activated during stress?
Which division of the autonomic nervous system is primarily activated during stress?
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Which of the following responses is most likely to occur as a result of increased sympathetic activity?
Which of the following responses is most likely to occur as a result of increased sympathetic activity?
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Which of the following is NOT an involuntary organ regulated by the autonomic nervous system?
Which of the following is NOT an involuntary organ regulated by the autonomic nervous system?
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How does the autonomic nervous system assist the endocrine system?
How does the autonomic nervous system assist the endocrine system?
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Which of the following describes the effects of the parasympathetic division?
Which of the following describes the effects of the parasympathetic division?
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What are the main pathways controlled by the sympathetic and parasympathetic divisions of the ANS?
What are the main pathways controlled by the sympathetic and parasympathetic divisions of the ANS?
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What is meant by the term 'autonomic' in the context of the autonomic nervous system?
What is meant by the term 'autonomic' in the context of the autonomic nervous system?
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What is the primary function of the parasympathetic division in the autonomic nervous system?
What is the primary function of the parasympathetic division in the autonomic nervous system?
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Which autonomic response occurs in the skin during an increase in sympathetic output?
Which autonomic response occurs in the skin during an increase in sympathetic output?
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During which of the following activities does the output of the parasympathetic division increase?
During which of the following activities does the output of the parasympathetic division increase?
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What effect does the parasympathetic division have on the lungs?
What effect does the parasympathetic division have on the lungs?
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Which of the following accurately describes the role of the sympathetic division concerning the heart?
Which of the following accurately describes the role of the sympathetic division concerning the heart?
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How does the parasympathetic division affect urinary bladder function?
How does the parasympathetic division affect urinary bladder function?
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What is the effect of the sympathetic nervous system on salivary gland secretion?
What is the effect of the sympathetic nervous system on salivary gland secretion?
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What autonomic effect occurs in the male reproductive organ due to sympathetic stimulation?
What autonomic effect occurs in the male reproductive organ due to sympathetic stimulation?
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What effect does adrenaline have on blood vessels in the skin?
What effect does adrenaline have on blood vessels in the skin?
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Which receptor type is responsible for the contraction of smooth muscle in blood vessels when stimulated by adrenaline?
Which receptor type is responsible for the contraction of smooth muscle in blood vessels when stimulated by adrenaline?
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Which type of adrenergic receptor promotes relaxation of smooth muscle in blood vessels?
Which type of adrenergic receptor promotes relaxation of smooth muscle in blood vessels?
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Where is the primary site of heart rate control located?
Where is the primary site of heart rate control located?
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What effect does sympathetic stimulation have on smooth muscle density?
What effect does sympathetic stimulation have on smooth muscle density?
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In terms of heart rate, how do sympathetic and parasympathetic stimulation generally compare?
In terms of heart rate, how do sympathetic and parasympathetic stimulation generally compare?
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Which receptor primarily causes cardiac muscle contraction?
Which receptor primarily causes cardiac muscle contraction?
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Which adrenergic receptors are involved in inhibiting norepinephrine release?
Which adrenergic receptors are involved in inhibiting norepinephrine release?
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What is the role of β-adrenergic receptors in the body?
What is the role of β-adrenergic receptors in the body?
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Which of the following organs does adrenaline stimulate vasodilation through β-adrenergic receptors?
Which of the following organs does adrenaline stimulate vasodilation through β-adrenergic receptors?
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What is the primary neurotransmitter released by postganglionic fibers of the sudomotor system?
What is the primary neurotransmitter released by postganglionic fibers of the sudomotor system?
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Which adrenergic receptor subtype is responsible for relaxation of smooth muscle in blood vessels?
Which adrenergic receptor subtype is responsible for relaxation of smooth muscle in blood vessels?
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Where are the preganglionic cell bodies of the sympathetic nervous system located?
Where are the preganglionic cell bodies of the sympathetic nervous system located?
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What is a unique feature of postganglionic fibers in the sympathetic nervous system?
What is a unique feature of postganglionic fibers in the sympathetic nervous system?
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Which structure does the sympathetic trunk consist of?
Which structure does the sympathetic trunk consist of?
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What type of neuron conveys information from the tissues to the central nervous system (CNS)?
What type of neuron conveys information from the tissues to the central nervous system (CNS)?
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What role do varicosities play in the sympathetic nervous system?
What role do varicosities play in the sympathetic nervous system?
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What is the primary neurotransmitter released by motor neurons in the somatic nervous system?
What is the primary neurotransmitter released by motor neurons in the somatic nervous system?
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During which type of event does the sympathetic division increase its output?
During which type of event does the sympathetic division increase its output?
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Which type of adrenergic receptor inhibits norepinephrine release?
Which type of adrenergic receptor inhibits norepinephrine release?
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The connection formed between the preganglionic and postganglionic neurons is known as what?
The connection formed between the preganglionic and postganglionic neurons is known as what?
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What is the typical ratio of preganglionic to postganglionic neurons linked in the sympathetic nervous system?
What is the typical ratio of preganglionic to postganglionic neurons linked in the sympathetic nervous system?
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What type of receptor is primarily associated with acetylcholine in the autonomic nervous system?
What type of receptor is primarily associated with acetylcholine in the autonomic nervous system?
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What is the physiological outcome of the 'fight or flight response'?
What is the physiological outcome of the 'fight or flight response'?
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What type of synaptic cleft molecule is responsible for signal transmission across the synapse?
What type of synaptic cleft molecule is responsible for signal transmission across the synapse?
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Which neurotransmitter is released at the postganglionic-effector cell junction in the parasympathetic nervous system?
Which neurotransmitter is released at the postganglionic-effector cell junction in the parasympathetic nervous system?
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What does convergence in the sympathetic nervous system refer to?
What does convergence in the sympathetic nervous system refer to?
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Which type of nicotinic receptor is specifically related to the neuromuscular junction?
Which type of nicotinic receptor is specifically related to the neuromuscular junction?
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What characterizes divergence in the sympathetic nervous system?
What characterizes divergence in the sympathetic nervous system?
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Which ganglia are located in the abdominal cavity for sympathetic innervation?
Which ganglia are located in the abdominal cavity for sympathetic innervation?
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What component is involved in cellular signaling through a second messenger system?
What component is involved in cellular signaling through a second messenger system?
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What type of neurons connect other neurons within the central nervous system?
What type of neurons connect other neurons within the central nervous system?
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Which type of muscarinic receptor is involved in inhibiting heart rate?
Which type of muscarinic receptor is involved in inhibiting heart rate?
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What is the effect of activated nicotinic receptors in the autonomic nervous system?
What is the effect of activated nicotinic receptors in the autonomic nervous system?
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Which pathway in the somatic nervous system is responsible for transmitting sensory information?
Which pathway in the somatic nervous system is responsible for transmitting sensory information?
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What characteristic defines ionotropic receptors?
What characteristic defines ionotropic receptors?
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What is the role of G proteins in metabotropic receptor signaling?
What is the role of G proteins in metabotropic receptor signaling?
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Study Notes
Course Details
- Course: MD137 Principles of Physiology
- Year: 2024-25
- Lecturer: Professor AM Wheatley
- Email: [email protected]
Autonomic Nervous System (ANS)
- The ANS controls involuntary functions, like sweating on a beach or the racing heart during a horror movie
- It acts without conscious thought, regulating the body's response to physical and emotional surroundings
- ANS functions:
- Maintains homeostasis (stable internal conditions)
- Coordinates responses to stress and exercise
- Supports endocrine system in regulating reproduction
- Involuntary organs regulated by the ANS:
- Heart
- Blood vessels
- Exocrine glands
- Visceral organs
Divisions of the ANS
- Sympathetic division:
- Activates during stress, anxiety, physical activity, fear, excitement, and metabolic resource use
- "Fight or flight" response
- Parasympathetic division:
- Active during sedentary activity, eating, and restoration of the body's reserves, and eliminating waste products
- "Rest and digest" response
- Enteric division:
- Controls the GI tract
Nervous System Components
- Central nervous system (CNS) includes:
- Brain
- Spinal cord
- Peripheral nervous system (PNS) includes:
- Somatic nervous system (controls skeletal muscle)
- Autonomic nervous system (controls involuntary functions)
Neurons
- Neurons are nerve cells that transmit electrical signals
- Types of neurons:
- Afferent neurons: carry sensory information from tissues/organs to the CNS
- Efferent neurons: carry motor information from the CNS to tissues/organs
- Interneurons: connect neurons within the CNS regions
Neurotransmitters in the ANS
- Acetylcholine (ACh):
- Preganglionic-postganglionic synapses in both parasympathetic and sympathetic systems use ACh
- Postganglionic-effector synapses in parasympathetic division use ACh
- Muscle type receptors are nicotinic
- A variation of receptors are muscarinic, which cause smooth muscle contractions, slower but longer lasting
- Norepinephrine (NE):
- In sympathetic postganglionic-effector synapses
- Binds to adrenergic receptors, which have varying affects in target organs
- One set never develops into a neuron, but into the adrenal medulla, which secretes epinephrine and norepinephrine into the bloodstream
- In sympathetic postganglionic-effector synapses
- There are multiple adrenergic receptors:
- Alpha-adrenergic (α) receptors: primarily cause vasoconstriction.
- Two subtype a1 and 2
- Beta-adrenergic (β) receptors: primarily cause vasodilation and other effects
- Two subtype B1 and B2
- Alpha-adrenergic (α) receptors: primarily cause vasoconstriction.
- The autonomic signalling pathway is through either one or two neurons.
Control of Heart Rate
- The heart rate is controlled (in part) by both sympathetic and parasympathetic nervous systems
- The SA node (sinoatrial node, in the atria) is the primary heart rate pacemaker
- Parasympathetic stimulation slows heart rate
- Sympathetic stimulation increases heart rate
Other Organ Control
- Specific examples: eye dilation and constriction, salivation, gastrointestinal function, liver glucose production, urinary bladder functions, male and female reproductive organs, and more.
Organization of the Sympathetic Division
- The sympathetic division is more complex.
- Preganglionic neurons are located in the thoracic and upper lumbar spinal cord.
- Axons of preganglionic neurons synapse with ganglia close to the spinal cord (paravertebral).
- Some preganglionic axons pass through without synapsing (splanchnic nerves) onto prevertebral ganglia (celiac, superior mesenteric, inferior mesenteric)
- Some other axons extend greater distances before synapsing
Convergence and Divergence
- Convergence: Many preganglionic neurons synapse with a single postganglionic neuron; important for fine control of peripheral effectors.
- Divergence: One preganglionic neuron synapses with many postganglionic neurons; critical for widespread sympathetic activation (e.g., "fight or flight").
ANS and Voluntary Control
- Some ANS functions are subject to voluntary influence (e.g., some aspects of bladder control).
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Description
Test your knowledge on the functions and activities of the autonomic nervous system, focusing on the roles of both the parasympathetic and sympathetic divisions. This quiz includes questions about the enteric nervous system and conditions affecting the sympathetic and parasympathetic responses.
