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Questions and Answers
Which cranial nerve is responsible for the constriction of pupils?
Which cranial nerve is responsible for the constriction of pupils?
- Oculomotor nerve (III) (correct)
- Glossopharyngeal nerve (IX)
- Vagus nerve (X)
- Facial nerve (VII)
What function is associated with the Vagus nerve (X)?
What function is associated with the Vagus nerve (X)?
- Constricts pupils
- Innervates the parotid salivary gland
- Produces tears
- Stimulates digestive glands (correct)
Where is the Myenteric plexus located?
Where is the Myenteric plexus located?
- Between longitudinal and circular muscle (correct)
- In the walls of the heart
- Outside the CNS
- Between circular muscle and luminal mucosa
Which of the following statements about postganglionic neurons is true?
Which of the following statements about postganglionic neurons is true?
Which plexus is the largest among the autonomic plexuses?
Which plexus is the largest among the autonomic plexuses?
What is the primary role of acetylcholinesterase (AChE)?
What is the primary role of acetylcholinesterase (AChE)?
Which type of anticholinesterase produces effects of long duration?
Which type of anticholinesterase produces effects of long duration?
Which of the following agents is categorized as a reversible acetylcholinesterase inhibitor?
Which of the following agents is categorized as a reversible acetylcholinesterase inhibitor?
What is one of the first principles of management for organophosphate poisoning?
What is one of the first principles of management for organophosphate poisoning?
Butyrylcholinesterase (BChE) is primarily produced in which organ?
Butyrylcholinesterase (BChE) is primarily produced in which organ?
What is the primary function of the autonomic nervous system?
What is the primary function of the autonomic nervous system?
Which effect is associated with Propranolol?
Which effect is associated with Propranolol?
Which part of the autonomic nervous system is responsible for the 'fight or flight' response?
Which part of the autonomic nervous system is responsible for the 'fight or flight' response?
What is the primary effect of Labetalol and carvedilol?
What is the primary effect of Labetalol and carvedilol?
What neurotransmitter is primarily used by the parasympathetic nervous system?
What neurotransmitter is primarily used by the parasympathetic nervous system?
Which statement about sympathetic and parasympathetic divisions is correct?
Which statement about sympathetic and parasympathetic divisions is correct?
Which situation would Acebutolol or Pindolol be least effective in treating?
Which situation would Acebutolol or Pindolol be least effective in treating?
Bradycardia typically causes which of the following effects?
Bradycardia typically causes which of the following effects?
Which of the following neurons would be classified as afferent neurons?
Which of the following neurons would be classified as afferent neurons?
Which of the following is true about bronchoconstriction?
Which of the following is true about bronchoconstriction?
What does the term 'thoracolumbar' refer to in the context of the autonomic nervous system?
What does the term 'thoracolumbar' refer to in the context of the autonomic nervous system?
Which division of the autonomic nervous system is primarily involved in the 'rest and digest' response?
Which division of the autonomic nervous system is primarily involved in the 'rest and digest' response?
What type of muscle contraction is stimulated by the sympathetic division's alpha receptors?
What type of muscle contraction is stimulated by the sympathetic division's alpha receptors?
What is the primary clinical use of atropine?
What is the primary clinical use of atropine?
Which of the following is a reversible cholinergic agonist?
Which of the following is a reversible cholinergic agonist?
Which agent is used to treat glaucoma by decreasing eye pressure?
Which agent is used to treat glaucoma by decreasing eye pressure?
What is the action of succinylcholine during surgery?
What is the action of succinylcholine during surgery?
What is the main effect of anticholinergic agents like scopolamine?
What is the main effect of anticholinergic agents like scopolamine?
What condition would necessitate the use of pralidoxime?
What condition would necessitate the use of pralidoxime?
Which adrenergic agonist is primarily used to treat hypotension?
Which adrenergic agonist is primarily used to treat hypotension?
What is the primary purpose of nicotine in out-of-hospital settings?
What is the primary purpose of nicotine in out-of-hospital settings?
Which of the following is classified as an irreversible cholinergic agent?
Which of the following is classified as an irreversible cholinergic agent?
What is the effect of ibuprofen on gastrointestinal motility?
What is the effect of ibuprofen on gastrointestinal motility?
Which agent is known to induce mydriasis?
Which agent is known to induce mydriasis?
In what scenario is methacholine clinically used?
In what scenario is methacholine clinically used?
What class of drugs does Ipratropium belong to?
What class of drugs does Ipratropium belong to?
Which drug primarily causes skeletal muscle contraction and is used in general anesthesia?
Which drug primarily causes skeletal muscle contraction and is used in general anesthesia?
Study Notes
Autonomic Nervous System
- Controls involuntary structures: smooth and cardiac muscles, glands
- Controlled by: brain stem, limbic system, and frontal lobes (by the hypothalamus)
- Function: maintain homeostasis of the internal environment along with the Endocrine system
- Has 2 neuron chain
Sympathetic (Fight or Flight)
- Also called thoracolumbar (T1-L2)
- Activates adrenal medulla to release norepinephrine and epinephrine
- Stimulate activities of the effector organs (except digestive organs)
- Functions for intense skeletal muscle activity
- Activated in stressful situations
- Axon: highly branched and affect many organs
- Divided into:
- Alpha ïƒ contraction of smooth muscle
- Beta 1 ïƒ metabolic functions
- Beta 2 ïƒ relaxation of smooth muscle
Parasympathetic (Rest and Digest)
- Also called Craniosacral (S2-S4)
- Functions for maintenance
- Activated in calm and rest situations
- Inhibit activities of the effector organs (except digestive organs)
- Axon: few branches and has localized effect
- Uses neurotransmitter acetylcholine
- Divided into:
- Nicotinic ïƒ uses an ion channel
- Muscarinic ïƒ uses G-protein receptor
- Cranial outflow:
- III 3 {Oculomotor} - pupils constrict
- VII 7 {Facial} - tears, nasal mucus, saliva
- IX 9 {Glossopharyngeal} – parotid salivary gland
- X 10 (Vagus) – visceral organs of thorax & abdomen: (stimulates digestive glands, increases motility of smooth muscle of digestive tract, decreases heart rate, bronchial constriction)
- Sacral outflow (S2-4):
- Form pelvic splanchnic nerves
- Supply 2nd half of the large intestine
- Supply all the pelvic (genitourinary) organs
Enteric Nervous System {ENS}
- Located within the wall of the digestive tract, from the Oesophagus to anus
- Divided into:
- Myenteric plexus {of Auerbach} ïƒ located between longitudinal and circular muscle
- Submucosal plexus {of Meissner} ïƒ located between circular muscle and luminal mucosa
Preganglionic Neurons
- Originate in the brain or spinal cord
- Short sympathetic and long parasympathetic
Postganglionic Neurons
- Originate in the ganglion located outside the CNS
- Long sympathetic and short parasympathetic
Sympathetic System: Postganglionic Cell Bodies
- Paravertebral ganglia ïƒ located at the sides of vertebrae and united by preganglionic into the sympathetic system (preganglionic are thoracolumbar) (postganglionic are cervical to coccyx)
- Prevertebral (preaortic) ganglia ïƒ located at the anterior to abdominal aorta, in plexuses surrounding its major branches (preganglionic nerves reach preventable ganglia via abdominopelvic splanchnic nerves)
Autonomic Plexuses
- Cardiac plexus ïƒ heart
- Pulmonary plexus ïƒ bronchial tree
- Celiac plexus ïƒ largest.
Cholinesterase
- Acetylcholinesterase (AChE) (choline esterase I, erythrocyte cholinesterase, RBC cholinesterase, acetylcholine acetylhydrolase) ïƒ neural synapses, neuromuscular junctions and RBC membranes
- Butyrylcholinesterase (BChE) (choline esterase II, pseudocholinesterase, plasma cholinesterase) ïƒ produced in the liver and found in the blood plasma
Anticholinesterases (Cholinesterase Inhibitors)
- Block hydrolysis of acetylcholine ïƒ (Parathion inhibits the action of the enzyme acetylcholinesterase leading to accumulation of Ach)
- Used as smart drugs (paralysis during anesthesia, myasthenia gravis, glaucoma, Alzheimer’s disease)
- 2 types of acetylcholinesterase inhibitors:
- Reversible ïƒ do not covalently modify acetylcholinesterase (combine with a residue of serine in the active site). Produce effects of moderate duration : E.g., carbamates, acridine
- Irreversible ïƒ organophosphates (phosphorylates the serine residue in the active site); produce effects of long duration (pesticide, nerve gas Sarin)
Organophosphate Compounds
- Drug: Ecothiophate
- Pesticides: Parathion, Malathion
- Nerve gases: Sarin, Soman, Tabun
Clinical Features of An Organophosphate Poisoning
- Includes: nausea, vomiting, diarrhea, blurred vision, bronchospasm (wheezing), bradycardia, muscle weakness, fasciculations, paralysis, seizures, coma
Principles of Management of Organophosphate Poisoning (ABC Drugs)
- Measures to prevent/reduce absorption (Transdermal/Oral ingestion):
- Wash with soap and water and remove clothes
- Gastric lavage
- Nicotine
Cholinergic Agonist
- Examples: Bethanechol, Pilocarpine, Neostigmine, Physostigmine, Ecothiophate, Isophlurophate
Organophosphate Antidotes
- Atropine, Pralidoxime
Cholinergic Parasympathetic Antagonist (Symp Like Effect)
- Examples: Atropine, Ipratropium, Scopolamine
Ganglion Blocker (Nn)
- Example: Nicotine
Anti-Nicotinic (Nm)
- Examples: Succinylcholine, Tubocurarine, Mivacurium
Adrenergic Sympathetic Agonist (Symp Like Effect)
- Direct-acting: Examples: Epinephrine (adrenaline), Dopamine, Dobutamine, Albuterol, Phenylephrine
- Non-selective: Examples: Propranolol
- Non-selective, A1 blocker: Examples: Labetalol, Carvedilol
- Partial agonist: Examples: Acebutalol, Pindolol
- Drugs used to treat: Bradycardia, Hypertension, Asthma, Miosis
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Description
Explore the intricacies of the Autonomic Nervous System, including the roles of the sympathetic and parasympathetic divisions. Understand how these systems work to maintain homeostasis and respond to stress. Test your knowledge on their functions and anatomical features.
