Sympathetic Nervous System Overview
100 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary effect of sympathetic stimulation on the esophagus?

  • Increases peristalsis
  • Enhances secretions
  • Stimulates bile production
  • Decreases peristalsis (correct)

    • Norepinephrine from the celiac ganglia promotes digestive activity.

    False

    What physiological response occurs in the liver during stress?

    Glycogenolysis

    The __________ nerve passes through chain ganglia and synapses in the celiac ganglia.

    <p>greater splanchnic</p> Signup and view all the answers

    Match the following sympathetic nervous system effects with their descriptions:

    <p>Inhibition of Digestive Processes = Reduces blood flow to the gastrointestinal tract Glycogenolysis = Increases blood glucose for energy Vasoconstriction = Reduces blood flow to non-essential organs Dilation of Bronchioles = Enhances airflow during stress</p> Signup and view all the answers

    Which of the following describes the role of the hypothalamus in the sympathetic nervous system?

    <p>Integrates sympathetic nervous system controls</p> Signup and view all the answers

    The sympathetic nervous system promotes micturition during stress.

    <p>False</p> Signup and view all the answers

    What is the effect of sympathetic stimulation on insulin production?

    <p>Inhibition of insulin production</p> Signup and view all the answers

    The __________ splanchnic nerve influences renal functions.

    <p>lesser</p> Signup and view all the answers

    Which component of the nervous system is responsible for the fight-or-flight response?

    <p>Sympathetic Nervous System</p> Signup and view all the answers

    What is the main role of the sympathetic nervous system?

    <p>Fight or flight response</p> Signup and view all the answers

    The sympathetic nervous system stimulates salivary glands to produce more saliva.

    <p>False</p> Signup and view all the answers

    Where are the cell bodies of preganglionic motor neurons in the sympathetic nervous system located?

    <p>Intermediolateral column of the spinal cord</p> Signup and view all the answers

    The sympathetic nervous system is part of the __________ nervous system.

    <p>autonomic</p> Signup and view all the answers

    Match the following ganglia with their respective locations:

    <p>Chain ganglia = Located laterally Collateral ganglia = Located anteriorly Superior cervical ganglion = Cervical region Middle cervical ganglion = Cervical region</p> Signup and view all the answers

    Which ganglia are specifically responsible for functions in the head and neck?

    <p>Superior cervical ganglion</p> Signup and view all the answers

    Norepinephrine increases lacrimation in the lacrimal glands.

    <p>False</p> Signup and view all the answers

    What effect does norepinephrine have on the pupil?

    <p>Pupillary dilation</p> Signup and view all the answers

    The thoracolumbar outflow ranges from vertebra T1 to __________.

    <p>L2</p> Signup and view all the answers

    Which plexus is responsible for increasing heart rate and contractility?

    <p>Cardiac plexus</p> Signup and view all the answers

    What is the main area from which the sympathetic nervous system fibers originate?

    <p>Thoracolumbar region</p> Signup and view all the answers

    Norepinephrine causes pupils to constrict, enhancing near vision.

    <p>False</p> Signup and view all the answers

    Which ganglia are primarily responsible for the sympathetic functions in the head and neck?

    <p>Superior cervical ganglion, middle cervical ganglion, inferior cervical ganglion</p> Signup and view all the answers

    The sympathetic nervous system decreases blood flow to salivary glands, leading to __________ saliva production.

    <p>viscous</p> Signup and view all the answers

    Match the following ganglia with their specific locations:

    <p>Superior cervical ganglion = Located laterally in the neck Middle cervical ganglion = Located laterally in the neck Collateral ganglia = Located anteriorly to the vertebral column Chain ganglia = Located laterally next to the spinal column</p> Signup and view all the answers

    What is the effect of norepinephrine on the ciliary muscle of the eye?

    <p>Causes relaxation for distant vision</p> Signup and view all the answers

    The middle cervical ganglion supplies sympathetic fibers to the heart.

    <p>True</p> Signup and view all the answers

    What is the role of the carotid plexus in the sympathetic nervous system?

    <p>Surrounds the internal carotid artery and supplies nerves to various structures in the head and neck.</p> Signup and view all the answers

    Postganglionic fibers from the superior cervical ganglion supply nerves to the __________ artery.

    <p>internal carotid</p> Signup and view all the answers

    Which of these effects is NOT associated with sympathetic stimulation?

    <p>Increased digestion</p> Signup and view all the answers

    What is the primary physiological effect of norepinephrine released from the celiac ganglia during a stress response?

    <p>Inhibit digestive activity</p> Signup and view all the answers

    The renal system is stimulated during stressful situations to increase urine production.

    <p>False</p> Signup and view all the answers

    What role does the greater splanchnic nerve play in the autonomic nervous system?

    <p>It transmits fibers to the celiac ganglia and influences abdominal organ functions.</p> Signup and view all the answers

    During stress, the __________ muscle in the bladder prevents urination.

    <p>detrusor</p> Signup and view all the answers

    Match the following ganglia with their primary functions:

    <p>Celiac Ganglia = Inhibits digestion and regulates blood supply to stomach Superior Mesenteric Ganglion = Regulates blood supply to small intestine Inferior Mesenteric Ganglion = Influences lower GI tract functions Aorticorenal Ganglia = Innervates renal function</p> Signup and view all the answers

    Which of the following best describes the role of the sympathetic nervous system during stress?

    <p>Increases heart rate and blood flow to muscles</p> Signup and view all the answers

    The hypothalamus has no role in regulating the sympathetic nervous system.

    <p>False</p> Signup and view all the answers

    What effect does sympathetic stimulation have on gallbladder contraction during stress?

    <p>It reduces contractions, inhibiting bile secretion.</p> Signup and view all the answers

    The __________ splanchnic nerve is responsible for regulating renal functions.

    <p>lesser</p> Signup and view all the answers

    Which hormone is primarily suppressed during sympathetic stimulation to increase blood glucose levels?

    <p>Insulin</p> Signup and view all the answers

    What is the primary function of norepinephrine in the sympathetic nervous system?

    <p>Promotes pupil dilation and lens flattening</p> Signup and view all the answers

    Preganglionic motor neuron cell bodies are located in the thoracic region of the spinal cord.

    <p>True</p> Signup and view all the answers

    Which ganglion is located superiorly in the cervical region and influences structures in the head?

    <p>Superior cervical ganglion</p> Signup and view all the answers

    The sympathetic nervous system fibers mainly originate from the thoracolumbar region, specifically from ______ to ______.

    <p>T1, L2</p> Signup and view all the answers

    Match the following ganglia to their respective roles in the sympathetic nervous system:

    <p>Superior cervical ganglion = Influences the eye and neck Middle cervical ganglion = Supplies fibers to the heart Inferior cervical ganglion = Supplies fibers to the lungs Collateral ganglia = Involved in prevertebral sympathetic functions</p> Signup and view all the answers

    Which of the following statements is true regarding the effects of sympathetic stimulation on the salivary glands?

    <p>It results in thick mucin production.</p> Signup and view all the answers

    Norepinephrine decreases lacrimation by constricting blood vessels in the lacrimal glands.

    <p>True</p> Signup and view all the answers

    What plexus is responsible for increasing heart rate and contractility?

    <p>Cardiac plexus</p> Signup and view all the answers

    The postganglionic fibers from the superior cervical ganglion surround the ______ artery.

    <p>internal carotid</p> Signup and view all the answers

    Which of the following is an effect of the sympathetic nervous system during stress?

    <p>Pupillary dilation</p> Signup and view all the answers

    What is the effect of sympathetic stimulation on the pyloric sphincter?

    <p>It contracts, slowing the passage of contents into the duodenum.</p> Signup and view all the answers

    The celiac ganglia primarily enhance digestive processes during the fight-or-flight response.

    <p>False</p> Signup and view all the answers

    What is glycogenolysis and why is it important during stress?

    <p>Glycogenolysis is the breakdown of glycogen to glucose, raising blood sugar levels for muscle activity during stress.</p> Signup and view all the answers

    The __________ nerve primarily regulates bladder function during stress.

    <p>superior hypogastric plexus</p> Signup and view all the answers

    Match the following effects with their physiological responses:

    <p>Inhibition of peristalsis = Decreased digestive activity Increased heart rate = Enhanced blood circulation Renin release = Increased blood pressure Relaxation of detrusor muscle = Inhibition of urination</p> Signup and view all the answers

    Which of the following hormones is suppressed to raise blood glucose levels during sympathetic activation?

    <p>Insulin</p> Signup and view all the answers

    The inferior mesenteric ganglion primarily influences upper gastrointestinal tract functions.

    <p>False</p> Signup and view all the answers

    Explain how the sympathetic nervous system regulates blood flow to vital organs during stress.

    <p>It constricts blood vessels in non-essential areas and redirects blood flow to vital organs.</p> Signup and view all the answers

    Sympathetic activation leads to __________ of blood vessels in the stomach, minimizing digestive activity.

    <p>constriction</p> Signup and view all the answers

    What physiological change occurs in the lung bronchioles due to sympathetic stimulation?

    <p>Dilation of bronchioles</p> Signup and view all the answers

    What is the primary effect of norepinephrine on the pupil during sympathetic stimulation?

    <p>Dilation</p> Signup and view all the answers

    The sympathetic nervous system primarily decreases heart rate and slows down digestive processes.

    <p>False</p> Signup and view all the answers

    Identify the region of the spinal cord where the sympathetic nervous system's preganglionic neurons are located.

    <p>Thoracic and lumbar regions</p> Signup and view all the answers

    The carotid plexus surrounds the __________ artery, supplying nerves to various structures in the head and neck.

    <p>internal carotid</p> Signup and view all the answers

    Match the ganglia to their respective locations:

    <p>Superior cervical ganglion = Cervical region Middle cervical ganglion = Cervical region Inferior cervical ganglion = Cervical region Collateral ganglia = Anterior to the vertebral column</p> Signup and view all the answers

    Which structure does norepinephrine influence to aid in accommodation for distant vision?

    <p>Ciliary muscle</p> Signup and view all the answers

    Postganglionic fibers from the superior cervical ganglion decrease salivation by enhancing blood flow to the salivary glands.

    <p>False</p> Signup and view all the answers

    What is the thoracolumbar outflow range for sympathetic nerve fibers?

    <p>T1 to L2</p> Signup and view all the answers

    Which plexus is responsible for increasing heart rate and contractility?

    <p>Cardiac plexus</p> Signup and view all the answers

    Norepinephrine reduces lacrimation by constricting __________ associated blood vessels.

    <p>lacrimal</p> Signup and view all the answers

    What effect does norepinephrine from the celiac ganglia have on digestive activity?

    <p>It inhibits peristalsis.</p> Signup and view all the answers

    Sympathetic stimulation increases urine production during stress.

    <p>False</p> Signup and view all the answers

    What is the role of the greater splanchnic nerve?

    <p>It carries sympathetic fibers to the celiac ganglia.</p> Signup and view all the answers

    The __________ muscle relaxes to prevent urination during stress.

    <p>detrusor</p> Signup and view all the answers

    Match the following organs or actions with their sympathetic response:

    <p>Gallbladder = Decreased secretion Adrenal medulla = Release of epinephrine Liver = Glycogenolysis Bladder = Inhibition of urination</p> Signup and view all the answers

    Which ganglia are involved in regulating blood supply to the small intestine?

    <p>Superior mesenteric ganglia</p> Signup and view all the answers

    The sympathetic nervous system supports reproductive functions during stress.

    <p>True</p> Signup and view all the answers

    What physiological change occurs in the liver during stressful situations?

    <p>Increased glucose production through glycogenolysis.</p> Signup and view all the answers

    The __________ nervous system is primarily responsible for the fight-or-flight response.

    <p>sympathetic</p> Signup and view all the answers

    Match the following hormones with their effect during sympathetic stimulation:

    <p>Glucagon = Raises blood glucose levels Insulin = Suppresses to maintain glucose levels Norepinephrine = Inhibits digestive activity Epinephrine = Enhances cardiovascular responses</p> Signup and view all the answers

    Which of the following hormones increases blood glucose levels during a stress response?

    <p>Glucagon</p> Signup and view all the answers

    The sympathetic stimulation leads to decreased heart rate during stressful situations.

    <p>False</p> Signup and view all the answers

    What effect does sympathetic stimulation have on the detrusor muscle of the bladder?

    <p>It relaxes the detrusor muscle.</p> Signup and view all the answers

    The ________ nerve influences the adrenal medulla to release epinephrine and norepinephrine.

    <p>greater splanchnic</p> Signup and view all the answers

    Match the following effects of the sympathetic nervous system with their corresponding descriptions:

    <p>Inhibition of digestive processes = Decreased peristalsis and secretions Glycogenolysis = Breakdown of glycogen to glucose Vasoconstriction = Reduced blood flow to non-essential organs Increased heart rate = Enhanced circulation during fight-or-flight</p> Signup and view all the answers

    Which ganglion is primarily responsible for regulating gastrointestinal functions during stress?

    <p>Celiac ganglion</p> Signup and view all the answers

    Sympathetic stimulation promotes increased urine production.

    <p>False</p> Signup and view all the answers

    What is the role of the hypothalamus in the sympathetic nervous system?

    <p>It integrates sympathetic responses.</p> Signup and view all the answers

    What area of the spinal cord is known as the thoracolumbar outflow for the sympathetic nervous system?

    <p>Thoracic vertebrae T1 to lumbar vertebra L2</p> Signup and view all the answers

    During stress, the pyloric sphincter may contract, slowing the passage of contents into the ________.

    <p>duodenum</p> Signup and view all the answers

    Preganglionic motor neurons of the sympathetic nervous system are located in the intermediolateral column of the spinal cord.

    <p>True</p> Signup and view all the answers

    Which of the following is an action associated with the lesser splanchnic nerve?

    <p>Inhibits peristalsis in the lower GI tract</p> Signup and view all the answers

    What is the effect of norepinephrine on the dilator pupillae muscle?

    <p>Pupillary dilation</p> Signup and view all the answers

    The middle cervical ganglion provides sympathetic fibers to the ______ and ______.

    <p>heart, lungs</p> Signup and view all the answers

    Match the sympathetic ganglia with their locations:

    <p>Superior cervical ganglion = Cervical region Middle cervical ganglion = Cervical region Inferior cervical ganglion = Cervical region Chain ganglia = Located laterally</p> Signup and view all the answers

    What is the primary function of the carotid plexus?

    <p>Supplies nerves to head and neck structures</p> Signup and view all the answers

    Norepinephrine increases blood flow to salivary glands, resulting in thinner saliva production.

    <p>False</p> Signup and view all the answers

    What region of the spine does the sympathetic nervous system primarily originate from?

    <p>Thoracic and lumbar regions</p> Signup and view all the answers

    The ______ effect of sympathetic stimulation on the heart increases heart rate and contractility.

    <p>positive chronotropic</p> Signup and view all the answers

    Which of the following structures does norepinephrine affect to aid in distant vision?

    <p>Ciliary muscle</p> Signup and view all the answers

    Study Notes

    Sympathetic Nervous System Overview

    • The sympathetic nervous system (SNS) is part of the autonomic nervous system and works alongside the parasympathetic nervous system (PNS).
    • Located from the thoracic vertebrae T1 to lumbar vertebra L2 (sometimes T3 or L3), this area is known as the thoracolumbar outflow.

    Preganglionic Motor Neurons and Ganglia

    • Preganglionic motor neuron cell bodies are found in the intermediolateral column of the spinal cord.
    • Peripheral nervous system ganglia consist of groups of cell bodies outside the CNS:
      • Chain ganglia (located laterally)
      • Collateral (or prevertebral) ganglia (located anteriorly).

    Chain Ganglia and Cervical Regions

    • Superior cervical ganglion (SCG), middle cervical ganglion (MCG), and inferior cervical ganglion (ICG) extend up towards the cervical region, influencing head and neck structures.
    • Preganglionic fibers from T1 to T3 synapse at the SCG to control functions of the eye, salivary glands, and other neck structures.

    Function of the Carotid Plexus

    • Postganglionic fibers from the SCG can surround the internal carotid artery forming the carotid plexus, supplying nerves to various structures in the head and neck.

    Effects on the Eye

    • Norepinephrine acts on the dilator pupillae muscle, resulting in pupillary dilation to enhance far vision.
    • Additionally, it influences the ciliary muscle for lens flattening, further aiding in accommodation for distant vision.

    Salivary and Lacrimal Glands

    • Norepinephrine decreases blood flow to salivary glands causing thick mucin production, leading to viscous saliva formation.
    • In lacrimal glands, norepinephrine reduces lacrimation by constricting associated blood vessels.

    Cardiac, Esophageal, and Pulmonary Plexuses

    • Middle cervical ganglion and inferior cervical ganglion provide sympathetic fibers to heart, lungs, and esophagus.
    • Cardiac plexus increases heart rate (positive chronotropic effect) and contractility, raising cardiac output.
    • Esophagus: sympathetic stimulation decreases peristalsis and secretions.
    • Pulmonary plexus dilates bronchioles, enhancing airflow during stress response.

    Greater Splanchnic Nerve and Celiac Ganglia

    • Fibers from T5 to T9 pass through chain ganglia as the greater splanchnic nerve and synapse in the celiac ganglia.
    • Celiac ganglia operate alongside the celiac trunk artery, supplying abdominal organs.

    Effects on Abdominal Organs

    • Norepinephrine from celiac ganglia inhibits peristalsis, reduces secretions, and constricts blood vessels to the stomach, minimizing digestive activity during fight-or-flight response.
    • The pyloric sphincter may contract, slowing the passage of contents into the duodenum, known as the interrogative reflex.

    Summary of Key Functions

    • The sympathetic nervous system primarily activates physiological changes to prepare the body for stressful situations (fight-or-flight response).
    • These changes include increased heart rate, dilation of pupils, inhibition of digestive processes, and a shift in blood flow away from non-essential areas during emergencies.### Overview of the Autonomic Nervous System's Role in Fight or Flight
    • Sympathetic Nervous System enhances physiological responses during stress, inhibiting non-essential functions (e.g., digestion).
    • Glycogenolysis occurs in the liver, converting glycogen to glucose to maintain energy levels for muscle contraction during stress.

    Liver Functions during Stress

    • Glycogenolysis: Breakdown of glycogen to glucose to raise blood sugar levels for muscle activity.
    • Inhibition of Biliary Tree Flow: Decreasing contractions in the gallbladder to reduce bile secretion, as fat digestion is not a priority during stress.
    • Inhibition of Insulin Production: Reducing insulin levels while stimulating glucagon from alpha cells to raise blood glucose.

    Pancreas and Hormonal Regulation

    • Islets of Langerhans: Comprising alpha cells (glucagon secretion) and beta cells (insulin secretion).
    • Increased Glucagon Production: Focus on elevating blood glucose levels by suppressing insulin from beta cells.

    Blood Supply and Ganglia Impact

    • Celiac Ganglia: Supplies stomach, reduces absorption, and decreases peristalsis in both the stomach and proximal duodenum.
    • Greater Splanchnic Nerve: Extends to adrenal medulla, bypassing ganglia. Stimulates chromaffin cells to release norepinephrine and epinephrine into circulation, causing widespread effects.

    Gastrointestinal Tract Effects

    • Decrease in Peristalsis and Secretion: The sympathetic response reduces digestive activity throughout the GI tract, particularly in small intestines.
    • Superior Mesenteric Ganglion: Receives fibers from the greater splanchnic nerve, regulating blood supply to the small intestine and proximal colon, decreasing peristalsis.

    Renal System Suppression

    • Lesser Splanchnic Nerve: Originates from T10-T11, innervates renal functions via aorticorenal ganglia.
    • Decreased Urine Production: Reduced renal blood flow and constriction of blood vessels divert blood to vital organs, limiting kidney function.
    • Renin Release: Juxtaglomerular cells in kidneys release renin due to sympathetic stimulation, influencing blood pressure regulation.

    Lumbar Splanchnic Nerves

    • Inferior Mesenteric Ganglion: Influences lower GI tract functions, particularly the descending colon and sigmoid region, by decreasing peristalsis when under stress.

    Urinary and Reproductive System Responses

    • Superior Hypogastric Plexus: Innervates bladder and urethral sphincters, regulating micturition and preventing voiding during stress conditions.
    • Detrusor Muscle: Relaxation prevents urination, while internal urethral sphincter contracts due to sympathetic action, inhibiting urination.

    Reproductive Effects

    • Nerve Pathways to Gonads: Involves fibers from both sympathetic and lumbar regions, contributing to reproductive functions such as ejaculation in males and uterine contractions in non-pregnant females.
    • Pregnancy Adaptation: Receptor switch in the uterus from alpha-1 to beta-2 during pregnancy prevents premature contractions, illustrating how the body adapts to changing physiological conditions.### Male Reproductive Anatomy
    • Prostate gland and seminal vesicles produce seminal fluid, important in male reproductive function.
    • Prostate and seminal vesicles are integral to male anatomy.

    Nervous System Components

    • Sacral splanchnic nerves play a role in lower body innervation.
    • Lumbar splanchnic nerves connect to superior hypogastric ganglion and inferior mesenteric ganglion.
    • Hypogastric nerves (right and left) are derived from superior hypogastric ganglion, contributing to the inferior hypogastric plexus.

    Inferior Hypogastric Plexus

    • The inferior hypogastric plexus is crucial for innervating the gonads.
    • Major contributions to this plexus come from the superior hypogastric ganglion and sacral splanchnic nerves.
    • Contributions from sacral splanchnic nerves are minimal compared to the superior hypogastric ganglion.

    Central Nervous System Influence

    • The hypothalamus, a gray matter structure in the diencephalon, integrates sympathetic nervous system controls.
    • Limbic nuclei also play a significant role in sympathetic nervous system regulation.
    • Cortical control can occur but is less common; biofeedback techniques allow some level of voluntary control over physiological responses like heart rate.

    Sympathetic Nervous System Regulation

    • Sympathetic control is influenced primarily by the hypothalamus and limbic system.
    • Presynaptic fibers stimulate cell bodies, leading to activation of preganglionic motor neurons, which in turn stimulate postganglionic neurons to target organs.
    • Higher brain functions may affect sympathetic responses indirectly through the hypothalamus and limbic structures.

    Sympathetic Nervous System Overview

    • The sympathetic nervous system (SNS) is a component of the autonomic nervous system, complementing the parasympathetic nervous system (PNS).
    • Spans from thoracic vertebrae T1 to lumbar vertebra L2, known as thoracolumbar outflow.

    Preganglionic Motor Neurons and Ganglia

    • Preganglionic motor neurons are located in the intermediolateral column of the spinal cord.
    • Peripheral ganglia comprise chain ganglia (lateral) and collateral ganglia (anterior).

    Chain Ganglia and Cervical Regions

    • Superior cervical ganglion (SCG), middle cervical ganglion (MCG), and inferior cervical ganglion (ICG) influence functions in head and neck.
    • Preganglionic fibers from T1 to T3 synapse at SCG affecting ocular and salivary functions.

    Function of the Carotid Plexus

    • Postganglionic fibers from SCG surround the internal carotid artery, forming the carotid plexus and supplying nerves to head and neck structures.

    Effects on the Eye

    • Norepinephrine induces dilation of the pupil via dilator pupillae muscle, enhancing far vision.
    • Also facilitates lens flattening by influencing ciliary muscles for better accommodation.

    Salivary and Lacrimal Glands

    • Norepinephrine reduces blood flow in salivary glands, producing thick mucin and viscous saliva.
    • In lacrimal glands, it decreases lacrimation by constricting blood vessels.

    Cardiac, Esophageal, and Pulmonary Plexuses

    • Middle and inferior cervical ganglia transmit sympathetic fibers to the heart, lungs, and esophagus.
    • Cardiac plexus increases heart rate and contractility, boosting cardiac output.
    • Sympathetic stimulation of the esophagus reduces peristalsis and secretions.
    • Pulmonary plexus dilates bronchioles, enhancing airflow during stress.

    Greater Splanchnic Nerve and Celiac Ganglia

    • Fibers from T5 to T9 travel as the greater splanchnic nerve and synapse in the celiac ganglia.
    • Celiac ganglia control blood flow to abdominal organs through the celiac trunk artery.

    Effects on Abdominal Organs

    • Norepinephrine from celiac ganglia inhibits peristalsis and reduces digestive secretions during stress.
    • The pyloric sphincter contracts, delaying gastric contents flow into the duodenum.

    Summary of Key Functions

    • SNS prepares the body for stress with physiological changes (fight-or-flight response).
    • Responses include raised heart rate, pupil dilation, digestion inhibition, and redirected blood flow.

    Overview of the Autonomic Nervous System's Role in Fight or Flight

    • The SNS stimulates responses that inhibit non-essential functions like digestion.
    • Glycogenolysis occurs in the liver to sustain energy by converting glycogen to glucose.

    Liver Functions during Stress

    • Glycogenolysis raises blood sugar for muscle activity.
    • Gallbladder contractions decrease, reducing bile secretion during stress.
    • Insulin production is inhibited, while glucagon is stimulated to maintain high blood glucose levels.

    Pancreas and Hormonal Regulation

    • Islets of Langerhans contain alpha cells (glucagon) and beta cells (insulin).
    • Increased glucagon production raises blood glucose levels, suppressing insulin secretion.

    Blood Supply and Ganglia Impact

    • Celiac ganglia supply the stomach and decrease absorption and peristalsis.
    • Greater splanchnic nerve stimulates adrenal medulla chromaffin cells for norepinephrine and epinephrine release.

    Gastrointestinal Tract Effects

    • The sympathetic response decreases GI tract digestive activity, especially in the small intestines.
    • Superior mesenteric ganglion regulates blood supply to the small intestine and colon.

    Renal System Suppression

    • Lesser splanchnic nerve, originating from T10-T11, affects renal function through aorticorenal ganglia.
    • Reduces urine output by constricting renal blood vessels and diverting blood to vital organs.
    • Renin release occurs from juxtaglomerular cells due to sympathetic stimulation, impacting blood pressure.

    Lumbar Splanchnic Nerves

    • Inferior mesenteric ganglion manages lower GI tract functions, particularly in stress situations.

    Urinary and Reproductive System Responses

    • Superior hypogastric plexus controls bladder and sphincters, inhibiting urination during stress.
    • Detrusor muscle relaxation prevents urination, while the internal sphincter contracts due to sympathetic activation.

    Reproductive Effects

    • Nerve pathways to the gonads involve fibers from sympathetic and lumbar regions, influencing male ejaculation and uterine contractions in females.
    • Pregnancy shifts uterine receptor sensitivity from alpha-1 to beta-2, preventing premature contractions.

    Male Reproductive Anatomy

    • Prostate gland and seminal vesicles are crucial for male reproductive function due to their role in fluid production.

    Nervous System Components

    • Sacral splanchnic and lumbar splanchnic nerves connect to superior hypogastric ganglion and inferior mesenteric ganglion.
    • Hypogastric nerves derive from superior hypogastric ganglion, contributing to inferior hypogastric plexus.

    Inferior Hypogastric Plexus

    • Crucial for gonad innervation, receiving significant contributions from the superior hypogastric ganglion.

    Central Nervous System Influence

    • Hypothalamus integrates SNS controls, with limbic nuclei influencing sympathetic regulation.
    • Higher brain function impacts sympathetic responses less commonly, with biofeedback potentially allowing voluntary control of reactions.

    Sympathetic Nervous System Regulation

    • Primarily influenced by the hypothalamus and limbic system.
    • Presynaptic fibers trigger preganglionic motor neuron activation, stimulating postganglionic neurons targeting organs.

    Sympathetic Nervous System Overview

    • The sympathetic nervous system (SNS) is a component of the autonomic nervous system, complementing the parasympathetic nervous system (PNS).
    • Spans from thoracic vertebrae T1 to lumbar vertebra L2, known as thoracolumbar outflow.

    Preganglionic Motor Neurons and Ganglia

    • Preganglionic motor neurons are located in the intermediolateral column of the spinal cord.
    • Peripheral ganglia comprise chain ganglia (lateral) and collateral ganglia (anterior).

    Chain Ganglia and Cervical Regions

    • Superior cervical ganglion (SCG), middle cervical ganglion (MCG), and inferior cervical ganglion (ICG) influence functions in head and neck.
    • Preganglionic fibers from T1 to T3 synapse at SCG affecting ocular and salivary functions.

    Function of the Carotid Plexus

    • Postganglionic fibers from SCG surround the internal carotid artery, forming the carotid plexus and supplying nerves to head and neck structures.

    Effects on the Eye

    • Norepinephrine induces dilation of the pupil via dilator pupillae muscle, enhancing far vision.
    • Also facilitates lens flattening by influencing ciliary muscles for better accommodation.

    Salivary and Lacrimal Glands

    • Norepinephrine reduces blood flow in salivary glands, producing thick mucin and viscous saliva.
    • In lacrimal glands, it decreases lacrimation by constricting blood vessels.

    Cardiac, Esophageal, and Pulmonary Plexuses

    • Middle and inferior cervical ganglia transmit sympathetic fibers to the heart, lungs, and esophagus.
    • Cardiac plexus increases heart rate and contractility, boosting cardiac output.
    • Sympathetic stimulation of the esophagus reduces peristalsis and secretions.
    • Pulmonary plexus dilates bronchioles, enhancing airflow during stress.

    Greater Splanchnic Nerve and Celiac Ganglia

    • Fibers from T5 to T9 travel as the greater splanchnic nerve and synapse in the celiac ganglia.
    • Celiac ganglia control blood flow to abdominal organs through the celiac trunk artery.

    Effects on Abdominal Organs

    • Norepinephrine from celiac ganglia inhibits peristalsis and reduces digestive secretions during stress.
    • The pyloric sphincter contracts, delaying gastric contents flow into the duodenum.

    Summary of Key Functions

    • SNS prepares the body for stress with physiological changes (fight-or-flight response).
    • Responses include raised heart rate, pupil dilation, digestion inhibition, and redirected blood flow.

    Overview of the Autonomic Nervous System's Role in Fight or Flight

    • The SNS stimulates responses that inhibit non-essential functions like digestion.
    • Glycogenolysis occurs in the liver to sustain energy by converting glycogen to glucose.

    Liver Functions during Stress

    • Glycogenolysis raises blood sugar for muscle activity.
    • Gallbladder contractions decrease, reducing bile secretion during stress.
    • Insulin production is inhibited, while glucagon is stimulated to maintain high blood glucose levels.

    Pancreas and Hormonal Regulation

    • Islets of Langerhans contain alpha cells (glucagon) and beta cells (insulin).
    • Increased glucagon production raises blood glucose levels, suppressing insulin secretion.

    Blood Supply and Ganglia Impact

    • Celiac ganglia supply the stomach and decrease absorption and peristalsis.
    • Greater splanchnic nerve stimulates adrenal medulla chromaffin cells for norepinephrine and epinephrine release.

    Gastrointestinal Tract Effects

    • The sympathetic response decreases GI tract digestive activity, especially in the small intestines.
    • Superior mesenteric ganglion regulates blood supply to the small intestine and colon.

    Renal System Suppression

    • Lesser splanchnic nerve, originating from T10-T11, affects renal function through aorticorenal ganglia.
    • Reduces urine output by constricting renal blood vessels and diverting blood to vital organs.
    • Renin release occurs from juxtaglomerular cells due to sympathetic stimulation, impacting blood pressure.

    Lumbar Splanchnic Nerves

    • Inferior mesenteric ganglion manages lower GI tract functions, particularly in stress situations.

    Urinary and Reproductive System Responses

    • Superior hypogastric plexus controls bladder and sphincters, inhibiting urination during stress.
    • Detrusor muscle relaxation prevents urination, while the internal sphincter contracts due to sympathetic activation.

    Reproductive Effects

    • Nerve pathways to the gonads involve fibers from sympathetic and lumbar regions, influencing male ejaculation and uterine contractions in females.
    • Pregnancy shifts uterine receptor sensitivity from alpha-1 to beta-2, preventing premature contractions.

    Male Reproductive Anatomy

    • Prostate gland and seminal vesicles are crucial for male reproductive function due to their role in fluid production.

    Nervous System Components

    • Sacral splanchnic and lumbar splanchnic nerves connect to superior hypogastric ganglion and inferior mesenteric ganglion.
    • Hypogastric nerves derive from superior hypogastric ganglion, contributing to inferior hypogastric plexus.

    Inferior Hypogastric Plexus

    • Crucial for gonad innervation, receiving significant contributions from the superior hypogastric ganglion.

    Central Nervous System Influence

    • Hypothalamus integrates SNS controls, with limbic nuclei influencing sympathetic regulation.
    • Higher brain function impacts sympathetic responses less commonly, with biofeedback potentially allowing voluntary control of reactions.

    Sympathetic Nervous System Regulation

    • Primarily influenced by the hypothalamus and limbic system.
    • Presynaptic fibers trigger preganglionic motor neuron activation, stimulating postganglionic neurons targeting organs.

    Sympathetic Nervous System Overview

    • The sympathetic nervous system (SNS) is a component of the autonomic nervous system, complementing the parasympathetic nervous system (PNS).
    • Spans from thoracic vertebrae T1 to lumbar vertebra L2, known as thoracolumbar outflow.

    Preganglionic Motor Neurons and Ganglia

    • Preganglionic motor neurons are located in the intermediolateral column of the spinal cord.
    • Peripheral ganglia comprise chain ganglia (lateral) and collateral ganglia (anterior).

    Chain Ganglia and Cervical Regions

    • Superior cervical ganglion (SCG), middle cervical ganglion (MCG), and inferior cervical ganglion (ICG) influence functions in head and neck.
    • Preganglionic fibers from T1 to T3 synapse at SCG affecting ocular and salivary functions.

    Function of the Carotid Plexus

    • Postganglionic fibers from SCG surround the internal carotid artery, forming the carotid plexus and supplying nerves to head and neck structures.

    Effects on the Eye

    • Norepinephrine induces dilation of the pupil via dilator pupillae muscle, enhancing far vision.
    • Also facilitates lens flattening by influencing ciliary muscles for better accommodation.

    Salivary and Lacrimal Glands

    • Norepinephrine reduces blood flow in salivary glands, producing thick mucin and viscous saliva.
    • In lacrimal glands, it decreases lacrimation by constricting blood vessels.

    Cardiac, Esophageal, and Pulmonary Plexuses

    • Middle and inferior cervical ganglia transmit sympathetic fibers to the heart, lungs, and esophagus.
    • Cardiac plexus increases heart rate and contractility, boosting cardiac output.
    • Sympathetic stimulation of the esophagus reduces peristalsis and secretions.
    • Pulmonary plexus dilates bronchioles, enhancing airflow during stress.

    Greater Splanchnic Nerve and Celiac Ganglia

    • Fibers from T5 to T9 travel as the greater splanchnic nerve and synapse in the celiac ganglia.
    • Celiac ganglia control blood flow to abdominal organs through the celiac trunk artery.

    Effects on Abdominal Organs

    • Norepinephrine from celiac ganglia inhibits peristalsis and reduces digestive secretions during stress.
    • The pyloric sphincter contracts, delaying gastric contents flow into the duodenum.

    Summary of Key Functions

    • SNS prepares the body for stress with physiological changes (fight-or-flight response).
    • Responses include raised heart rate, pupil dilation, digestion inhibition, and redirected blood flow.

    Overview of the Autonomic Nervous System's Role in Fight or Flight

    • The SNS stimulates responses that inhibit non-essential functions like digestion.
    • Glycogenolysis occurs in the liver to sustain energy by converting glycogen to glucose.

    Liver Functions during Stress

    • Glycogenolysis raises blood sugar for muscle activity.
    • Gallbladder contractions decrease, reducing bile secretion during stress.
    • Insulin production is inhibited, while glucagon is stimulated to maintain high blood glucose levels.

    Pancreas and Hormonal Regulation

    • Islets of Langerhans contain alpha cells (glucagon) and beta cells (insulin).
    • Increased glucagon production raises blood glucose levels, suppressing insulin secretion.

    Blood Supply and Ganglia Impact

    • Celiac ganglia supply the stomach and decrease absorption and peristalsis.
    • Greater splanchnic nerve stimulates adrenal medulla chromaffin cells for norepinephrine and epinephrine release.

    Gastrointestinal Tract Effects

    • The sympathetic response decreases GI tract digestive activity, especially in the small intestines.
    • Superior mesenteric ganglion regulates blood supply to the small intestine and colon.

    Renal System Suppression

    • Lesser splanchnic nerve, originating from T10-T11, affects renal function through aorticorenal ganglia.
    • Reduces urine output by constricting renal blood vessels and diverting blood to vital organs.
    • Renin release occurs from juxtaglomerular cells due to sympathetic stimulation, impacting blood pressure.

    Lumbar Splanchnic Nerves

    • Inferior mesenteric ganglion manages lower GI tract functions, particularly in stress situations.

    Urinary and Reproductive System Responses

    • Superior hypogastric plexus controls bladder and sphincters, inhibiting urination during stress.
    • Detrusor muscle relaxation prevents urination, while the internal sphincter contracts due to sympathetic activation.

    Reproductive Effects

    • Nerve pathways to the gonads involve fibers from sympathetic and lumbar regions, influencing male ejaculation and uterine contractions in females.
    • Pregnancy shifts uterine receptor sensitivity from alpha-1 to beta-2, preventing premature contractions.

    Male Reproductive Anatomy

    • Prostate gland and seminal vesicles are crucial for male reproductive function due to their role in fluid production.

    Nervous System Components

    • Sacral splanchnic and lumbar splanchnic nerves connect to superior hypogastric ganglion and inferior mesenteric ganglion.
    • Hypogastric nerves derive from superior hypogastric ganglion, contributing to inferior hypogastric plexus.

    Inferior Hypogastric Plexus

    • Crucial for gonad innervation, receiving significant contributions from the superior hypogastric ganglion.

    Central Nervous System Influence

    • Hypothalamus integrates SNS controls, with limbic nuclei influencing sympathetic regulation.
    • Higher brain function impacts sympathetic responses less commonly, with biofeedback potentially allowing voluntary control of reactions.

    Sympathetic Nervous System Regulation

    • Primarily influenced by the hypothalamus and limbic system.
    • Presynaptic fibers trigger preganglionic motor neuron activation, stimulating postganglionic neurons targeting organs.

    Sympathetic Nervous System Overview

    • The sympathetic nervous system (SNS) is a component of the autonomic nervous system, complementing the parasympathetic nervous system (PNS).
    • Spans from thoracic vertebrae T1 to lumbar vertebra L2, known as thoracolumbar outflow.

    Preganglionic Motor Neurons and Ganglia

    • Preganglionic motor neurons are located in the intermediolateral column of the spinal cord.
    • Peripheral ganglia comprise chain ganglia (lateral) and collateral ganglia (anterior).

    Chain Ganglia and Cervical Regions

    • Superior cervical ganglion (SCG), middle cervical ganglion (MCG), and inferior cervical ganglion (ICG) influence functions in head and neck.
    • Preganglionic fibers from T1 to T3 synapse at SCG affecting ocular and salivary functions.

    Function of the Carotid Plexus

    • Postganglionic fibers from SCG surround the internal carotid artery, forming the carotid plexus and supplying nerves to head and neck structures.

    Effects on the Eye

    • Norepinephrine induces dilation of the pupil via dilator pupillae muscle, enhancing far vision.
    • Also facilitates lens flattening by influencing ciliary muscles for better accommodation.

    Salivary and Lacrimal Glands

    • Norepinephrine reduces blood flow in salivary glands, producing thick mucin and viscous saliva.
    • In lacrimal glands, it decreases lacrimation by constricting blood vessels.

    Cardiac, Esophageal, and Pulmonary Plexuses

    • Middle and inferior cervical ganglia transmit sympathetic fibers to the heart, lungs, and esophagus.
    • Cardiac plexus increases heart rate and contractility, boosting cardiac output.
    • Sympathetic stimulation of the esophagus reduces peristalsis and secretions.
    • Pulmonary plexus dilates bronchioles, enhancing airflow during stress.

    Greater Splanchnic Nerve and Celiac Ganglia

    • Fibers from T5 to T9 travel as the greater splanchnic nerve and synapse in the celiac ganglia.
    • Celiac ganglia control blood flow to abdominal organs through the celiac trunk artery.

    Effects on Abdominal Organs

    • Norepinephrine from celiac ganglia inhibits peristalsis and reduces digestive secretions during stress.
    • The pyloric sphincter contracts, delaying gastric contents flow into the duodenum.

    Summary of Key Functions

    • SNS prepares the body for stress with physiological changes (fight-or-flight response).
    • Responses include raised heart rate, pupil dilation, digestion inhibition, and redirected blood flow.

    Overview of the Autonomic Nervous System's Role in Fight or Flight

    • The SNS stimulates responses that inhibit non-essential functions like digestion.
    • Glycogenolysis occurs in the liver to sustain energy by converting glycogen to glucose.

    Liver Functions during Stress

    • Glycogenolysis raises blood sugar for muscle activity.
    • Gallbladder contractions decrease, reducing bile secretion during stress.
    • Insulin production is inhibited, while glucagon is stimulated to maintain high blood glucose levels.

    Pancreas and Hormonal Regulation

    • Islets of Langerhans contain alpha cells (glucagon) and beta cells (insulin).
    • Increased glucagon production raises blood glucose levels, suppressing insulin secretion.

    Blood Supply and Ganglia Impact

    • Celiac ganglia supply the stomach and decrease absorption and peristalsis.
    • Greater splanchnic nerve stimulates adrenal medulla chromaffin cells for norepinephrine and epinephrine release.

    Gastrointestinal Tract Effects

    • The sympathetic response decreases GI tract digestive activity, especially in the small intestines.
    • Superior mesenteric ganglion regulates blood supply to the small intestine and colon.

    Renal System Suppression

    • Lesser splanchnic nerve, originating from T10-T11, affects renal function through aorticorenal ganglia.
    • Reduces urine output by constricting renal blood vessels and diverting blood to vital organs.
    • Renin release occurs from juxtaglomerular cells due to sympathetic stimulation, impacting blood pressure.

    Lumbar Splanchnic Nerves

    • Inferior mesenteric ganglion manages lower GI tract functions, particularly in stress situations.

    Urinary and Reproductive System Responses

    • Superior hypogastric plexus controls bladder and sphincters, inhibiting urination during stress.
    • Detrusor muscle relaxation prevents urination, while the internal sphincter contracts due to sympathetic activation.

    Reproductive Effects

    • Nerve pathways to the gonads involve fibers from sympathetic and lumbar regions, influencing male ejaculation and uterine contractions in females.
    • Pregnancy shifts uterine receptor sensitivity from alpha-1 to beta-2, preventing premature contractions.

    Male Reproductive Anatomy

    • Prostate gland and seminal vesicles are crucial for male reproductive function due to their role in fluid production.

    Nervous System Components

    • Sacral splanchnic and lumbar splanchnic nerves connect to superior hypogastric ganglion and inferior mesenteric ganglion.
    • Hypogastric nerves derive from superior hypogastric ganglion, contributing to inferior hypogastric plexus.

    Inferior Hypogastric Plexus

    • Crucial for gonad innervation, receiving significant contributions from the superior hypogastric ganglion.

    Central Nervous System Influence

    • Hypothalamus integrates SNS controls, with limbic nuclei influencing sympathetic regulation.
    • Higher brain function impacts sympathetic responses less commonly, with biofeedback potentially allowing voluntary control of reactions.

    Sympathetic Nervous System Regulation

    • Primarily influenced by the hypothalamus and limbic system.
    • Presynaptic fibers trigger preganglionic motor neuron activation, stimulating postganglionic neurons targeting organs.

    Sympathetic Nervous System Overview

    • The sympathetic nervous system (SNS) is a component of the autonomic nervous system, complementing the parasympathetic nervous system (PNS).
    • Spans from thoracic vertebrae T1 to lumbar vertebra L2, known as thoracolumbar outflow.

    Preganglionic Motor Neurons and Ganglia

    • Preganglionic motor neurons are located in the intermediolateral column of the spinal cord.
    • Peripheral ganglia comprise chain ganglia (lateral) and collateral ganglia (anterior).

    Chain Ganglia and Cervical Regions

    • Superior cervical ganglion (SCG), middle cervical ganglion (MCG), and inferior cervical ganglion (ICG) influence functions in head and neck.
    • Preganglionic fibers from T1 to T3 synapse at SCG affecting ocular and salivary functions.

    Function of the Carotid Plexus

    • Postganglionic fibers from SCG surround the internal carotid artery, forming the carotid plexus and supplying nerves to head and neck structures.

    Effects on the Eye

    • Norepinephrine induces dilation of the pupil via dilator pupillae muscle, enhancing far vision.
    • Also facilitates lens flattening by influencing ciliary muscles for better accommodation.

    Salivary and Lacrimal Glands

    • Norepinephrine reduces blood flow in salivary glands, producing thick mucin and viscous saliva.
    • In lacrimal glands, it decreases lacrimation by constricting blood vessels.

    Cardiac, Esophageal, and Pulmonary Plexuses

    • Middle and inferior cervical ganglia transmit sympathetic fibers to the heart, lungs, and esophagus.
    • Cardiac plexus increases heart rate and contractility, boosting cardiac output.
    • Sympathetic stimulation of the esophagus reduces peristalsis and secretions.
    • Pulmonary plexus dilates bronchioles, enhancing airflow during stress.

    Greater Splanchnic Nerve and Celiac Ganglia

    • Fibers from T5 to T9 travel as the greater splanchnic nerve and synapse in the celiac ganglia.
    • Celiac ganglia control blood flow to abdominal organs through the celiac trunk artery.

    Effects on Abdominal Organs

    • Norepinephrine from celiac ganglia inhibits peristalsis and reduces digestive secretions during stress.
    • The pyloric sphincter contracts, delaying gastric contents flow into the duodenum.

    Summary of Key Functions

    • SNS prepares the body for stress with physiological changes (fight-or-flight response).
    • Responses include raised heart rate, pupil dilation, digestion inhibition, and redirected blood flow.

    Overview of the Autonomic Nervous System's Role in Fight or Flight

    • The SNS stimulates responses that inhibit non-essential functions like digestion.
    • Glycogenolysis occurs in the liver to sustain energy by converting glycogen to glucose.

    Liver Functions during Stress

    • Glycogenolysis raises blood sugar for muscle activity.
    • Gallbladder contractions decrease, reducing bile secretion during stress.
    • Insulin production is inhibited, while glucagon is stimulated to maintain high blood glucose levels.

    Pancreas and Hormonal Regulation

    • Islets of Langerhans contain alpha cells (glucagon) and beta cells (insulin).
    • Increased glucagon production raises blood glucose levels, suppressing insulin secretion.

    Blood Supply and Ganglia Impact

    • Celiac ganglia supply the stomach and decrease absorption and peristalsis.
    • Greater splanchnic nerve stimulates adrenal medulla chromaffin cells for norepinephrine and epinephrine release.

    Gastrointestinal Tract Effects

    • The sympathetic response decreases GI tract digestive activity, especially in the small intestines.
    • Superior mesenteric ganglion regulates blood supply to the small intestine and colon.

    Renal System Suppression

    • Lesser splanchnic nerve, originating from T10-T11, affects renal function through aorticorenal ganglia.
    • Reduces urine output by constricting renal blood vessels and diverting blood to vital organs.
    • Renin release occurs from juxtaglomerular cells due to sympathetic stimulation, impacting blood pressure.

    Lumbar Splanchnic Nerves

    • Inferior mesenteric ganglion manages lower GI tract functions, particularly in stress situations.

    Urinary and Reproductive System Responses

    • Superior hypogastric plexus controls bladder and sphincters, inhibiting urination during stress.
    • Detrusor muscle relaxation prevents urination, while the internal sphincter contracts due to sympathetic activation.

    Reproductive Effects

    • Nerve pathways to the gonads involve fibers from sympathetic and lumbar regions, influencing male ejaculation and uterine contractions in females.
    • Pregnancy shifts uterine receptor sensitivity from alpha-1 to beta-2, preventing premature contractions.

    Male Reproductive Anatomy

    • Prostate gland and seminal vesicles are crucial for male reproductive function due to their role in fluid production.

    Nervous System Components

    • Sacral splanchnic and lumbar splanchnic nerves connect to superior hypogastric ganglion and inferior mesenteric ganglion.
    • Hypogastric nerves derive from superior hypogastric ganglion, contributing to inferior hypogastric plexus.

    Inferior Hypogastric Plexus

    • Crucial for gonad innervation, receiving significant contributions from the superior hypogastric ganglion.

    Central Nervous System Influence

    • Hypothalamus integrates SNS controls, with limbic nuclei influencing sympathetic regulation.
    • Higher brain function impacts sympathetic responses less commonly, with biofeedback potentially allowing voluntary control of reactions.

    Sympathetic Nervous System Regulation

    • Primarily influenced by the hypothalamus and limbic system.
    • Presynaptic fibers trigger preganglionic motor neuron activation, stimulating postganglionic neurons targeting organs.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Explore the intricacies of the sympathetic nervous system (SNS) in this quiz, which discusses its role alongside the parasympathetic system and its anatomical features. Learn about the location of preganglionic motor neurons and the structure of ganglia, including chain and collateral ganglia. This comprehensive overview covers how the SNS influences functions in the cervical region.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser