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Questions and Answers
What type of fibers are responsible for transmitting signals to skeletal muscles?
What type of fibers are responsible for transmitting signals to skeletal muscles?
- Postganglionic sympathetic fibers
- Preganglionic fibers
- Somatic motor fibers (correct)
- Sympathetic fibers
Which component is involved in the transmission of signals to sweat glands?
Which component is involved in the transmission of signals to sweat glands?
- Somatic fiber
- Preganglionic sympathetic fiber
- Postganglionic sympathetic fiber (correct)
- Somatic motor neuron
Identify the structure that conveys sympathetic signals to the target organs:
Identify the structure that conveys sympathetic signals to the target organs:
- Soma of somatic motor neuron
- Somatic effector
- White ramus (correct)
- Spinal nerve
Which structure is responsible for innervating piloerector muscles?
Which structure is responsible for innervating piloerector muscles?
What type of neuron primarily connects the spinal cord to the sympathetic ganglion?
What type of neuron primarily connects the spinal cord to the sympathetic ganglion?
What function is associated with the ciliary ganglion in relation to the eye?
What function is associated with the ciliary ganglion in relation to the eye?
Which of the following ganglia is associated with the parotid salivary gland?
Which of the following ganglia is associated with the parotid salivary gland?
Which cranial nerve is primarily responsible for tears and nasal secretion?
Which cranial nerve is primarily responsible for tears and nasal secretion?
What is the primary role of the vagus nerve in relation to the abdominal viscera?
What is the primary role of the vagus nerve in relation to the abdominal viscera?
The pterygopalatine ganglion is primarily associated with which of the following functions?
The pterygopalatine ganglion is primarily associated with which of the following functions?
What type of neurons are primarily involved in the parasympathetic division?
What type of neurons are primarily involved in the parasympathetic division?
Which of the following best describes the function of the cardiac plexus?
Which of the following best describes the function of the cardiac plexus?
Which sacral nerve structure is involved in controlling functions of the bladder?
Which sacral nerve structure is involved in controlling functions of the bladder?
What type of nerve fibers exit the sympathetic chain via the gray ramus?
What type of nerve fibers exit the sympathetic chain via the gray ramus?
Which organs are primarily affected by the splanchnic nerve route?
Which organs are primarily affected by the splanchnic nerve route?
What is the function of the sympathetic nerve route?
What is the function of the sympathetic nerve route?
What is the primary structure where postganglionic sympathetic neurons reside?
What is the primary structure where postganglionic sympathetic neurons reside?
Which route do most sweat glands and blood vessels in skeletal muscles primarily utilize?
Which route do most sweat glands and blood vessels in skeletal muscles primarily utilize?
Which of the following glands is NOT typically affected by the sympathetic nerve route?
Which of the following glands is NOT typically affected by the sympathetic nerve route?
What is the role of the cervical ganglia in sympathetic innervation?
What is the role of the cervical ganglia in sympathetic innervation?
Which of the following statements about splanchnic nerves is accurate?
Which of the following statements about splanchnic nerves is accurate?
What distinguishes the sympathetic division from other divisions of the autonomic nervous system?
What distinguishes the sympathetic division from other divisions of the autonomic nervous system?
Which neurotransmitter is primarily released by postganglionic sympathetic fibers?
Which neurotransmitter is primarily released by postganglionic sympathetic fibers?
What is the main anatomical feature that connects each paravertebral ganglion to a spinal nerve?
What is the main anatomical feature that connects each paravertebral ganglion to a spinal nerve?
What type of fibers are the preganglionic neurons in the sympathetic division?
What type of fibers are the preganglionic neurons in the sympathetic division?
How do postganglionic fibers commonly leave the sympathetic ganglia?
How do postganglionic fibers commonly leave the sympathetic ganglia?
What is a significant characteristic of the sympathetic chain ganglia?
What is a significant characteristic of the sympathetic chain ganglia?
Which anatomical structures are primarily innervated by the sympathetic nerves?
Which anatomical structures are primarily innervated by the sympathetic nerves?
What happens to postganglionic fibers after entering the sympathetic chain?
What happens to postganglionic fibers after entering the sympathetic chain?
Which receptors do adrenergic fibers primarily target in target organs?
Which receptors do adrenergic fibers primarily target in target organs?
What type of fibers primarily enter the sympathetic chain via the white communicating ramus?
What type of fibers primarily enter the sympathetic chain via the white communicating ramus?
Which anatomical structure is NOT a part of the sympathetic chain ganglia?
Which anatomical structure is NOT a part of the sympathetic chain ganglia?
What is the primary function of the enteric nervous system?
What is the primary function of the enteric nervous system?
Where are the preganglionic neurosomas located in the sympathetic division?
Where are the preganglionic neurosomas located in the sympathetic division?
Which area of the spinal cord is NOT involved in the formation of pelvic splanchnic nerves?
Which area of the spinal cord is NOT involved in the formation of pelvic splanchnic nerves?
What condition is characterized by the absence of the enteric nervous system in a specific region of the colon?
What condition is characterized by the absence of the enteric nervous system in a specific region of the colon?
Which neurotransmitters are primarily involved in autonomic nervous system signaling?
Which neurotransmitters are primarily involved in autonomic nervous system signaling?
What can result from megacolon related to Hirschsprung disease?
What can result from megacolon related to Hirschsprung disease?
Which organ systems are involved in the regulation of normal digestive function alongside the enteric nervous system?
Which organ systems are involved in the regulation of normal digestive function alongside the enteric nervous system?
What is the primary role of the inferior hypogastric plexus?
What is the primary role of the inferior hypogastric plexus?
How many neurons compose the enteric nervous system?
How many neurons compose the enteric nervous system?
Which muscle components does the enteric nervous system primarily innervate?
Which muscle components does the enteric nervous system primarily innervate?
What is the risk associated with Hirschsprung disease if left untreated?
What is the risk associated with Hirschsprung disease if left untreated?
What is the function of the cardiac plexus?
What is the function of the cardiac plexus?
Which part of the digestive tract does NOT receive innervation from the enteric nervous system?
Which part of the digestive tract does NOT receive innervation from the enteric nervous system?
What is a common symptom associated with megacolon?
What is a common symptom associated with megacolon?
What is the primary function of the autonomic nervous system?
What is the primary function of the autonomic nervous system?
Which term was coined by Walter Cannon in relation to the autonomic nervous system?
Which term was coined by Walter Cannon in relation to the autonomic nervous system?
Which of the following is NOT a component controlled by the autonomic nervous system?
Which of the following is NOT a component controlled by the autonomic nervous system?
What does denervation hypersensitivity refer to?
What does denervation hypersensitivity refer to?
What neurotransmitter is primarily associated with postganglionic sympathetic fibers?
What neurotransmitter is primarily associated with postganglionic sympathetic fibers?
Which receptors are associated with cholinergic fibers in the autonomic nervous system?
Which receptors are associated with cholinergic fibers in the autonomic nervous system?
Where do the sympathetic preganglionic neurons originate from?
Where do the sympathetic preganglionic neurons originate from?
Which structure is NOT considered a visceral effector?
Which structure is NOT considered a visceral effector?
Which division of the autonomic nervous system is responsible for 'fight or flight' responses?
Which division of the autonomic nervous system is responsible for 'fight or flight' responses?
Which neurotransmitter is predominantly released by parasympathetic postganglionic neurons?
Which neurotransmitter is predominantly released by parasympathetic postganglionic neurons?
Which cranial nerve is involved in the parasympathetic division and controls eye functions?
Which cranial nerve is involved in the parasympathetic division and controls eye functions?
Which part of the autonomic nervous system manages the body's rest and digest functions?
Which part of the autonomic nervous system manages the body's rest and digest functions?
Which of the following is true about the autonomic nervous system?
Which of the following is true about the autonomic nervous system?
What effect would denervation of autonomic nerves have on muscle responses?
What effect would denervation of autonomic nerves have on muscle responses?
Flashcards
Parasympathetic Division
Parasympathetic Division
The branch of the autonomic nervous system responsible for "rest and digest" functions, slowing heart rate, increasing digestion, and promoting relaxation.
Preganglionic Neurons
Preganglionic Neurons
Neurons in the parasympathetic division that originate in the brain stem or sacral spinal cord and extend to autonomic ganglia.
Postganglionic Neurons
Postganglionic Neurons
Neurons in the parasympathetic division that receive signals from preganglionic neurons and project to target organs.
Autonomic Ganglia
Autonomic Ganglia
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Oculomotor Nerve (CN III)
Oculomotor Nerve (CN III)
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Pterygopalatine Ganglion
Pterygopalatine Ganglion
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Facial Nerve (CN VII)
Facial Nerve (CN VII)
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Glossopharyngeal Nerve (CN IX)
Glossopharyngeal Nerve (CN IX)
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Autonomic Nervous System (ANS)
Autonomic Nervous System (ANS)
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Visceral Motor System
Visceral Motor System
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Homeostasis
Homeostasis
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Flight-or-Fight Response
Flight-or-Fight Response
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Denervation Hypersensitivity
Denervation Hypersensitivity
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Sympathetic Division
Sympathetic Division
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Acetylcholine (ACh)
Acetylcholine (ACh)
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Norepinephrine (NE)
Norepinephrine (NE)
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Adrenergic Receptors
Adrenergic Receptors
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Muscarinic Receptors
Muscarinic Receptors
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Nicotinic Receptors
Nicotinic Receptors
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Somatic Motor Neuron
Somatic Motor Neuron
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Sympathetic Nerve
Sympathetic Nerve
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Spinal Preganglionic Nerve
Spinal Preganglionic Nerve
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Postganglionic Sympathetic Fiber
Postganglionic Sympathetic Fiber
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White Ramus
White Ramus
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Splanchnic Nerve
Splanchnic Nerve
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Gray Ramus
Gray Ramus
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Collateral Ganglia
Collateral Ganglia
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Sympathetic Chain Ganglia
Sympathetic Chain Ganglia
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Sympathetic Nerve Route
Sympathetic Nerve Route
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Carotid Plexus
Carotid Plexus
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Cardiac Nerves
Cardiac Nerves
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Piloerector Muscles
Piloerector Muscles
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Sympathetic Nervous System
Sympathetic Nervous System
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Thoracolumbar Division
Thoracolumbar Division
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Preganglionic Fibers
Preganglionic Fibers
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Postganglionic Fibers
Postganglionic Fibers
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Paravertebral Ganglia
Paravertebral Ganglia
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White Communicating Ramus
White Communicating Ramus
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Gray Communicating Ramus
Gray Communicating Ramus
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Sympathetic Nerve Fibers
Sympathetic Nerve Fibers
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What is the role of acetylcholine and norepinephrine in the sympathetic nervous system?
What is the role of acetylcholine and norepinephrine in the sympathetic nervous system?
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What are adrenergic receptors?
What are adrenergic receptors?
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What does 'cholinergic fibers' refer to?
What does 'cholinergic fibers' refer to?
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What are the three main courses that postganglionic fibers can take after entering the sympathetic chain?
What are the three main courses that postganglionic fibers can take after entering the sympathetic chain?
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Enteric Nervous System
Enteric Nervous System
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Hirschsprung Disease
Hirschsprung Disease
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Megacolon
Megacolon
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Colonic Gangrene
Colonic Gangrene
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Peritonitis
Peritonitis
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Autonomic Neurons
Autonomic Neurons
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Sympathetic and Parasympathetic
Sympathetic and Parasympathetic
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Pelvic Splanchnic Nerves
Pelvic Splanchnic Nerves
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Inferior Hypogastric Plexus
Inferior Hypogastric Plexus
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Celiac Ganglion
Celiac Ganglion
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Cardiac Plexus
Cardiac Plexus
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Pulmonary Plexus
Pulmonary Plexus
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Esophageal Plexus
Esophageal Plexus
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Abdominal Aortic Plexus
Abdominal Aortic Plexus
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Normal Digestive Function (Regulation)
Normal Digestive Function (Regulation)
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Study Notes
Autonomic Nervous System
- The autonomic nervous system (ANS) is a motor nervous system controlling glands, cardiac muscle, and smooth muscle.
- It's also called the visceral motor system.
- The ANS is usually involuntary, unlike the somatic nervous system, which is usually voluntary.
- The ANS controls visceral organs of the thoracic and abdominal cavity, as well as some structures in the body wall.
Comparison of Somatic and Autonomic Nervous Systems
- Effectors: Somatic- skeletal muscle; Autonomic- glands, smooth muscle, and cardiac muscle.
- Control: Somatic- usually voluntary; Autonomic- usually involuntary.
- Distal nerve endings: Somatic- neuromuscular junctions; Autonomic- varicosities.
- Efferent pathways: Somatic- one nerve fiber from CNS to effector; no ganglia; Autonomic- two nerve fibers from CNS to effector; synapse at a ganglion.
- Neurotransmitters: Somatic- acetylcholine (ACh); Autonomic- ACh and norepinephrine (NE).
- Effect on target cells: Somatic- always excitatory; Autonomic- excitatory or inhibitory.
- Effect of denervation: Somatic- flaccid paralysis; Autonomic- denervation hypersensitivity.
Introduction to Autonomic Nervous System
- Autonomic means "self-governed"; the autonomic nervous system (ANS) is independent of our will.
- The ANS regulates fundamental states and life processes, including heart rate, blood pressure, and body temperature.
- Walter Cannon coined the terms "homeostasis" and "fight-or-flight."
- Animals without an ANS cannot survive on their own (must be kept warm and stress-free).
General Properties of the Autonomic Nervous System
- The ANS is a motor nervous system controlling glands, cardiac muscle, and smooth muscle.
- It can also be called a visceral motor system (e.g., viscera of thoracic and abdominal cavities).
- Some parts of the body wall are also affected. (e.g., cutaneous blood vessels, sweat glands, piloerector muscles "goose bumps").
Autonomic Nervous System (Continued)
- The ANS carries out actions involuntarily, without conscious intent or awareness.
- Visceral effectors do not depend on the ANS to function, but the ANS does regulate their activity to meet body needs.
- Denervation hypersensitivity—exaggerated responses of cardiac and smooth muscle if autonomic nerves are severed.
Comparison of Sympathetic and Parasympathetic Divisions
- Origin in CNS: Sympathetic- thoracolumbar; Parasympathetic- craniosacral.
- Location of ganglia: Sympathetic- paravertebral and prevertebral ganglia; Parasympathetic- near or within target organs.
- Fiber lengths: Sympathetic- short preganglionic, long postganglionic; Parasympathetic- long preganglionic, short postganglionic
- Neural divergence: Sympathetic- extensive; Parasympathetic- minimal.
- Effects of system: Sympathetic- often widespread and general; Parasympathetic- more specific and local.
The Sympathetic Division
- The sympathetic division is also known as the thoracolumbar division. It originates in the thoracic and lumbar regions of the spinal cord.
- Preganglionic neurosomas are located in the lateral horns and adjacent regions of the spinal cord gray matter.
- Preganglionic fibers synapse in lateral ganglia located adjacent to the spinal cord.
- Fibers exiting the spinal cord (T1-L2) synapse with the paravertebral chain of ganglia.
- The location and arrangement of sympathetic ganglia give rise to three routes (spinal nerve, sympathetic nerve, and splanchnic nerve) that sympathetic nerve fibers take to reach their destinations.
- This division has a widespread effect on the body.
The Parasympathetic Division
- The parasympathetic division is also called the craniosacral division.
- It originates in the brain and sacral regions of the spinal cord.
- Preganglionic neurons originate in the midbrain, pons, and medulla, from nuclei of cranial nerves III, VII, IX, and X. These neurons exit the brain and travel to target organs.
- Also long preganglionic fibers emerge from the sacral spinal cord segments (S2-S4). These fibers synapse with ganglionic neurons near or within their target organs.
- The parasympathetic division has a more localized effect on the body.
The Enteric Nervous System
- The enteric nervous system (ENS) is a complex network of neurons regulating the digestive tract.
- It's located within the walls of the digestive tract, functioning almost entirely without CNS input
- It innervates smooth muscle and glands.
- Composed of approximately 100 million neurons.
- Has its own reflex arcs, regulating motility and secretion,
- Functions include controlling motility and secretion in the digestive system.
Visceral Reflexes
- Visceral reflexes are unconscious, automatic, stereotypical responses to stimulation involving visceral receptors and effectors.
- The reflex arc includes receptors (detect stretch, tissue damage, blood chemicals, body temperature), afferent neurons (transmit signals to the CNS), integrating centers (interneurons in the CNS), efferent neurons (transmit signals away from the CNS), and effectors. (carry out the response).
- The ANS is the efferent pathway for visceral reflexes.
Baroreflex
- Detects high blood pressure using arterial stretch receptors.
- Afferent neuron sends signals to the CNS.
- Efferent signals via the vagus nerve slow the heart, reducing blood pressure.
Micturition Reflex
- A reflex regulating urination.
Divisions of the Autonomic Nervous System
- The sympathetic and parasympathetic divisions often innervate the same target organ, causing either cooperative or antagonistic effects.
- Sympathetic division prepares the body for activity (fight or flight).
- Increases heart rate, blood pressure, airflow, glucose levels, etc. Reduces blood flow to the skin and the digestive tract.
- Parasympathetic division calms the body maintaining bodily functions (rest or digest).
- Digestion and elimination.
Autonomic Output Pathways
- The ANS has components in both the central (CNS) and peripheral nervous systems (PNS).
- It involves Control nuclei in the hypothalamus and other brainstem regions, motor neurons in the spinal cord and peripheral ganglia, nerve fibers traveling through cranial and spinal nerves.
- The output pathways contrast to somatic pathways because signals must pass across two neurons to reach their destination, forming a synapse in an autonomic ganglion.
Neurotransmitters and Their Receptors
- Acetylcholine (ACh) is secreted by all preganglionic neurons.
- Two types of cholinergic receptors: muscarinic and nicotinic.
- Norepinephrine (NE), secreted by most sympathetic postganglionic neurons.
- Two types of adrenergic receptors: alpha and beta.
Dual Innervation
- Most viscera receive nerve fibers from both parasympathetic and sympathetic nervous systems; often causing contrasting effects.
- Both divisions can exert antagonistic effects (i.e., opposite effects).
- In some cases, the two divisions act cooperatively (i.e., unified overall effect) on different effectors.
Control Without Dual Innervation
- Some effectors receive only sympathetic fibers (e.g., adrenal medulla; arrector pili muscles; sweat glands).
- The sympathetic division exerts a significant role in regulating blood pressure and blood flow.
Central Control of Autonomic Function
- ANS function is regulated by different levels of the CNS.
- Cerebral cortex, hypothalamus, and brainstem nuclei influence autonomic function.
- The hypothalamus plays a crucial role as a major visceral motor control center for primitive functions (e.g., hunger, thirst, sex).
Drugs and the Nervous System
- Neuropharmacology is the study of the effects of drugs on the nervous system.
- Drugs can enhance or suppress the activities of sympathetic or parasympathetic systems, affecting target organ function.
Anatomy of the Autonomic Nervous System
- The study includes expected learning outcomes, namely identifying anatomical components and nerve pathways of sympathetic and parasympathetic divisions, relating the adrenal glands to the sympathetic nervous system, and describing the enteric nervous system of the digestive tract and explaining its significance.
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Description
Test your knowledge on the human nervous system with this quiz that focuses on fibers, ganglia, and cranial nerves related to muscle innervation and autonomic functions. Explore the roles of various nerves and ganglia in regulating bodily functions, including those associated with the sympathetic and parasympathetic divisions.
