Autonomic Nervous System Structure
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Questions and Answers

What is the main function of the somatic nervous system?

  • To transmit sensory information to the brain
  • To regulate the body's skeletal muscles (correct)
  • To control involuntary activities of visceral muscles
  • To coordinate involuntary activities of internal organs and glands

    • Where is the cell body of the preganglionic neuron typically located in the autonomic nervous system?

  • In the peripherals of the nervous system
  • In the somatic nervous system
  • In the autonomic ganglion
  • In the lateral horn of the gray matter of the spinal cord or in the brainstem (correct)

    • Which division of the autonomic nervous system is characterized by preganglionic neurons located in the thoracic and lumbar regions of the spinal cord?

  • Sympathetic division (correct)
  • Peripheral nervous system
  • Somatic nervous system
  • Parasympathetic division

    • What is the typical neurotransmitter released by sympathetic neurons?

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

    Which type of neuron typically releases acetylcholine as its neurotransmitter in the autonomic nervous system?

    <p>Parasympathetic neuron</p> Signup and view all the answers

    What is a characteristic of the autonomic nervous system in relation to effector organs?

    <p>Most effector organs receive innervation from both the sympathetic and parasympathetic parts of the autonomic nervous system</p> Signup and view all the answers

    What type of receptors are primarily activated by epinephrine at low doses?

    <p>Beta receptors</p> Signup and view all the answers

    What is the effect of the sympathetic nervous system on the bronchial tree?

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

    What is the primary function of the adrenal medulla in response to sympathetic stimulation?

    <p>Producing epinephrine and norepinephrine</p> Signup and view all the answers

    What is the effect of norepinephrine on the heart?

    <p>Increased heart rate</p> Signup and view all the answers

    What is the effect of dopamine on the kidneys?

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

    Which nerve is parasympathetic to the heart?

    <p>Vagus nerve</p> Signup and view all the answers

    What is the primary use of fenoldopam IV?

    <p>Rapid vasodilation for severe hypertension</p> Signup and view all the answers

    What is the effect of epinephrine on blood pressure at high doses?

    <p>Increased blood pressure</p> Signup and view all the answers

    What is the primary use of isoproterenol in patients with asthma?

    <p>Relief of bronchospasm</p> Signup and view all the answers

    What is the effect of the parasympathetic nervous system on the bronchial tree?

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

    What is the primary action of alpha adrenergic blockers on blood vessels?

    <p>Decrease sympathetic tone of blood vessels</p> Signup and view all the answers

    Which drug is used to control episodes of hypertension in pheochromocytoma before surgery?

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

    What is the effect of activation of Alpha (α) 1 receptors?

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

    Which drug is linked to intraoperative floppy iris syndrome (IFIS), a risk factor for complications during cataract surgery?

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

    What is the effect of Beta Blockers on the heart?

    <p>Decrease heart rate</p> Signup and view all the answers

    Which drug can be used for in hypertensive emergency situations?

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

    What is the effect of Guanethidine on the peripheral nervous system?

    <p>Decreases peripheral vascular resistance</p> Signup and view all the answers

    Which drug is used to primarily improve muscle function in individuals with Myasthenia Gravis?

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

    What is the effect of Reserpine on neurotransmitters?

    <p>Decreases dopamine levels in the brain</p> Signup and view all the answers

    Which neurotransmitter is responsible for the action of constricting the pupil via parasympathetic innervation in the Iris Sphincter?

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

    What is the effect of alpha 2 activation on aqueous humor production?

    <p>Decrease in aqueous humor production</p> Signup and view all the answers

    Which medication is commonly used to treat open-angle glaucoma by inducing miosis and enhancing accommodation?

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

    What is the therapeutic use of Echothiophate?

    <p>Management of chronic open-angle glaucoma</p> Signup and view all the answers

    Which medication is used to differentiate between second and third neuron involvement in Horner's Syndrome?

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

    What is the effect of beta blockers on aqueous humor production?

    <p>Decrease in aqueous humor production</p> Signup and view all the answers

    Which medication is commonly used to treat dry eyes and mouth in patients with Sjogren's syndrome?

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

    What is the antidote for tubocurarine and neuromuscular blockers?

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

    What is the therapeutic use of Pralidoxime?

    <p>Antidote for nerve gas poisoning</p> Signup and view all the answers

    Which medication is a cardio-selective beta blocker?

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

    What is the effect of acetylcholine on muscarinic receptors?

    <p>Decreased heart rate and smooth muscle contraction</p> Signup and view all the answers

    What is the antidote for organophosphate intoxication, particularly from insecticides?

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

    What is the mechanism of action of Ipratropium?

    <p>Decreases smooth muscle contraction of bronchi</p> Signup and view all the answers

    What medication is used to treat dystonia in patients undergoing treatment with antipsychotic medications?

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

    Which medication is used in emergency situations to lower blood pressure?

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

    What is the medication of choice for rapid endotracheal intubation during anesthesia induction?

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

    What type of receptors do ganglionic blockers act on?

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

    Which medication is used as an alternative in cycloplegic refraction, especially when accommodative esotropia is involved?

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

    What is a prolonged asthma attack that doesn't respond to typical drug therapy?

    <p>Status asthmaticus</p> Signup and view all the answers

    What is the antidote for atropine overdose?

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

    What is the lethal dose of atropine in children?

    <p>10 mg</p> Signup and view all the answers

    What is the mechanism of action of Bacitracin?

    <p>Prevents the formation of a chain of sugar molecules</p> Signup and view all the answers

    What type of spectrum does Bacitracin have?

    <p>Narrow spectrum</p> Signup and view all the answers

    What is the warning associated with systemic use of Bacitracin?

    <p>Renal toxicity</p> Signup and view all the answers

    What is the mechanism of action of Erythromycin?

    <p>Inhibits bacterial protein synthesis</p> Signup and view all the answers

    What is the treatment of choice for external hordeolum?

    <p>Topical antibiotics</p> Signup and view all the answers

    What is a characteristic feature of the infiltrate associated with Pseudomonas infections?

    <p>It is often described as gray in color</p> Signup and view all the answers

    What is a concerning complication of Pseudomonas keratitis?

    <p>Corneal perforation</p> Signup and view all the answers

    What is a characteristic of Pseudomonas keratitis?

    <p>It progresses rapidly</p> Signup and view all the answers

    What is the location of the infection in Pseudomonas keratitis?

    <p>Central location of the cornea</p> Signup and view all the answers

    What is often seen in Pseudomonas keratitis?

    <p>Epithelial defect</p> Signup and view all the answers

    What is the mechanism of action of polymyxin B?

    <p>It interacts with the phospholipids of bacterial cell membranes, disrupting its osmosis.</p> Signup and view all the answers

    What is the primary target of dicloxacillin in bacterial cell walls?

    <p>Penicillin-binding proteins</p> Signup and view all the answers

    What is the main adverse effect of cephalexin in individuals with impaired kidney function?

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

    What is the mechanism of action of cephalexin in bacterial cells?

    <p>All of the above</p> Signup and view all the answers

    What is the class of antibiotics that may be considered for internal hordeolum if a patient has allergies to penicillin or cephalosporin?

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

    What is the primary indication for the use of levofloxacin in ophthalmology?

    <p>Acute Bacterial Conjunctivitis</p> Signup and view all the answers

    What is the primary mechanism of action of aminoglycosides in bacterial cells?

    <p>Inhibiting bacterial protein synthesis</p> Signup and view all the answers

    What is the limitation of using aminoglycosides in acute bacterial conjunctivitis?

    <p>They are typically used for short-term treatment only</p> Signup and view all the answers

    What is the mechanism of action of bacitracin ointment in bacterial cells?

    <p>It interacts with the phospholipids of bacterial cell membranes, disrupting its osmosis.</p> Signup and view all the answers

    What is the primary use of fluoroquinolones in ophthalmology?

    <p>Treating acute bacterial conjunctivitis</p> Signup and view all the answers

    What is a characteristic of Chlamydia trachomatis?

    <p>It needs a host cell to grow and reproduce</p> Signup and view all the answers

    What is the difference between trachoma and inclusion conjunctivitis?

    <p>Trachoma is caused by serotypes A, B, Ba, and C, while inclusion conjunctivitis is caused by serotypes D to K</p> Signup and view all the answers

    What is the sequela of trachoma if left untreated?

    <p>Preventable blindness</p> Signup and view all the answers

    What is the stage of trachoma characterized by the extension of follicles beyond the superior limbus into Herbert pits?

    <p>Stage III</p> Signup and view all the answers

    What is the characteristic feature of trachoma stage IV?

    <p>Extensive scarring and corneal pannus</p> Signup and view all the answers

    What is the most common bacterium causing keratitis in contact lens wearers?

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

    What is the characteristic feature of an ulcer caused by Streptococcus pneumoniae?

    <p>Gray-yellow color with a disc-like shape</p> Signup and view all the answers

    What is the characteristic feature of an ulcer caused by Staphylococcus pneumoniae?

    <p>Well-defined, white-grey, or creamy in color</p> Signup and view all the answers

    What is the effect of Chlamydia infection on the eye?

    <p>It causes unilateral conjunctivitis with hyperemia, follicles, and mucopurulent discharge</p> Signup and view all the answers

    What is the sequela of untreated Chlamydia infection?

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

    What is the mechanism of action of Bacitracin?

    <p>It prevents the formation of a chain of sugar molecules that bacteria need to build their protective cell wall</p> Signup and view all the answers

    What is the primary indication for the use of fluoroquinolones in ophthalmology?

    <p>Bacterial angular blepharitis</p> Signup and view all the answers

    What is the effect of Bacitracin on bacterial cells?

    <p>It effectively kills bacteria by preventing the formation of their protective cell wall</p> Signup and view all the answers

    What is the primary difference between Meibomian Seborrhea and Meibomianitis?

    <p>Excessive production of sebum versus inflammation of the meibomian glands</p> Signup and view all the answers

    What is the typical color of the infiltrate associated with Pseudomonas infections?

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

    What is usually seen in conjunction with the infiltrate in Pseudomonas keratitis?

    <p>Epithelial defect</p> Signup and view all the answers

    What is the rapid progression of Pseudomonas keratitis likely to lead to?

    <p>Ring ulcer</p> Signup and view all the answers

    What is the primary difference between Chlamydia trachomatis serotypes D to K and serotypes A, B, Ba, and C?

    <p>Serotypes A, B, Ba, and C cause trachoma, while serotypes D to K cause inclusion conjunctivitis</p> Signup and view all the answers

    What is the characteristic feature of an ulcer caused by Streptococcus pneumoniae?

    <p>The ulcer is gray-yellow in color and has a disc-like shape</p> Signup and view all the answers

    What is the main mechanism of action of Polymyxin B?

    <p>It interacts with the phospholipids of bacterial cell membranes, disrupting its osmosis.</p> Signup and view all the answers

    What is the most common bacterium causing keratitis in contact lens wearers?

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

    What is the primary effect of Dicloxacillin on bacterial cells?

    <p>It disrupts the formation of bacterial cell walls by attaching to proteins called penicillin-binding proteins.</p> Signup and view all the answers

    What is the effect of untreated trachoma?

    <p>It leads to blindness if left untreated</p> Signup and view all the answers

    What is the characteristic feature of Pseudomonas keratitis?

    <p>The infiltrate is well-defined and appears white-gray in color</p> Signup and view all the answers

    What is the primary use of Cephalexin?

    <p>To treat internal hordeolum caused by Gram-positive bacteria.</p> Signup and view all the answers

    What is the stage of trachoma characterized by the development of conjunctival scarring?

    <p>Stage III</p> Signup and view all the answers

    What is the common adverse effect of Cephalexin and Dicloxacillin?

    <p>All of the above</p> Signup and view all the answers

    What is the effect of Neomycin on the eye?

    <p>It causes corneal toxicity</p> Signup and view all the answers

    What is the alternative antibiotic to Cephalexin for internal hordeolum treatment?

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

    What is the primary difference between inclusion conjunctivitis and trachoma?

    <p>Inclusion conjunctivitis is caused by Chlamydia trachomatis serotypes D to K, while trachoma is caused by serotypes A, B, Ba, and C</p> Signup and view all the answers

    What is the primary use of Levofloxacin in ophthalmology?

    <p>To treat acute bacterial conjunctivitis caused by Haemophilus.</p> Signup and view all the answers

    What is the effect of untreated Chlamydia infection?

    <p>It leads to blindness if left untreated</p> Signup and view all the answers

    What is the limitation of using Aminoglycosides for acute bacterial conjunctivitis?

    <p>It is only effective for short-term treatment.</p> Signup and view all the answers

    What is the primary mechanism of action of Bacitracin ointment?

    <p>It interacts with the phospholipids of bacterial cell membranes, disrupting its osmosis.</p> Signup and view all the answers

    What is the primary characteristic of trachoma stage IV?

    <p>It is characterized by extensive scarring and corneal pannus</p> Signup and view all the answers

    What is the primary use of Polymyxin B/Bacitracin ointment?

    <p>To treat internal hordeolum caused by Gram-positive bacteria.</p> Signup and view all the answers

    What is the primary target of Dicloxacillin in bacterial cell walls?

    <p>Penicillin-binding proteins</p> Signup and view all the answers

    What is the primary mechanism of action of calcium carbonate?

    <p>Neutralizes hydrochloric acid</p> Signup and view all the answers

    Which antibiotic subclass exhibits concentration-dependent killing?

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

    What is the characteristic of time-dependent killing antibiotics?

    <p>Need to be present in the body for a longer time</p> Signup and view all the answers

    What is the effect of sodium bicarbonate on stomach acid?

    <p>Neutralizes excess stomach acid</p> Signup and view all the answers

    Which of the following is NOT true regarding Minimum Inhibitory Concentrations (MICs)?

    <p>MICs are the highest concentration of an antibiotic that kills bacteria</p> Signup and view all the answers

    What is the primary use of calcium carbonate?

    <p>To relieve heartburn and indigestion symptoms</p> Signup and view all the answers

    What is the primary goal of determining the minimum inhibitory concentration (MIC) of an antimicrobial?

    <p>To determine the minimum concentration of an antimicrobial required to inhibit the growth of a microorganism.</p> Signup and view all the answers

    Which type of antibiotic is most effective when its concentration is maintained above the MIC for as long as possible?

    <p>Time-dependent antibiotics</p> Signup and view all the answers

    What is the primary goal of pulsed dosing in antimicrobial therapy?

    <p>To achieve therapeutic drug levels above the MIC early in treatment</p> Signup and view all the answers

    Which type of antibiotic is effective against a wide variety of microbial species?

    <p>Broad-spectrum antibiotics</p> Signup and view all the answers

    What is the primary characteristic of narrow-spectrum antibiotics?

    <p>Effective against a single or limited group of organisms</p> Signup and view all the answers

    Which type of antibiotic is known to cause ototoxicity?

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

    Which type of antibiotic is most effective when its concentration is higher, rather than when it stays in the body for a longer period?

    <p>Concentration-dependent antibiotics</p> Signup and view all the answers

    Which antibiotic is commonly associated with hypersensitivity reactions?

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

    What is the primary benefit of using pulsed dosing in antimicrobial therapy?

    <p>Minimizing the risk of toxicity</p> Signup and view all the answers

    What is the primary difference between time-dependent and concentration-dependent antibiotics?

    <p>Concentration-dependent antibiotics are effective when their concentration is higher, rather than when they stay in the body for a longer period</p> Signup and view all the answers

    Which category describes antibiotics derived from natural sources but chemically modified in the laboratory?

    <p>Semi-synthetic</p> Signup and view all the answers

    What is the mechanism of action of β-lactam antibiotics?

    <p>Inhibition of penicillin-binding proteins (PBPs)</p> Signup and view all the answers

    Which type of antibiotic is effective against both gram-positive and gram-negative bacteria?

    <p>Broad-spectrum antibiotics</p> Signup and view all the answers

    What is the primary advantage of using broad-spectrum antibiotics?

    <p>They are effective against a wide variety of microbial species</p> Signup and view all the answers

    Which antibiotic class primarily exerts its bactericidal effect by inhibiting cell wall synthesis?

    <p>β-lactams</p> Signup and view all the answers

    What is the mechanism of action of fluoroquinolones?

    <p>Inhibition of DNA gyrase and topoisomerase IV</p> Signup and view all the answers

    Are fluoroquinolones bactericidal or bacteriostatic?

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

    Which antibiotic is commonly associated with broad-spectrum activity?

    <p>Both Ciprofloxacin and Ofloxacin</p> Signup and view all the answers

    How does metronidazole primarily exert its bactericidal effect?

    <p>Damage to bacterial DNA</p> Signup and view all the answers

    What is the parent drug of the quinolone antibiotic class?

    <p>Nalidixic acid</p> Signup and view all the answers

    What is the primary reason why drug combination therapy is used instead of using a single antibiotic?

    <p>To reduce the risk of antibiotic resistance</p> Signup and view all the answers

    What is the mechanism of antibiotic resistance that involves modifying the target site of antibiotics?

    <p>Modification of target site</p> Signup and view all the answers

    What is the term used to describe the enhanced effectiveness of antibiotics when used in combination?

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

    What is the primary disadvantage of using bacteriostatic agents in combination with other antibiotics?

    <p>They can stop bacteria from growing, making other antibiotics less effective</p> Signup and view all the answers

    What is the term used to describe the ability of antibiotics to target a wide range of bacterial species?

    <p>Broad-spectrum</p> Signup and view all the answers

    What is the mechanism of antibiotic resistance that involves the production of enzymes that can degrade antibiotics?

    <p>Enzymatic inactivation</p> Signup and view all the answers

    What is the primary advantage of using extended-spectrum antibiotics?

    <p>They can target a wide range of bacterial species</p> Signup and view all the answers

    What is the mechanism of antibiotic resistance that involves the transfer of genes encoding antibiotic resistance from one bacterium to another?

    <p>Transfer of drug resistance by R factors</p> Signup and view all the answers

    What is the primary disadvantage of using drug combination therapy?

    <p>It can cause growth-dependent effectiveness</p> Signup and view all the answers

    What is the term used to describe the ability of antibiotics to target a specific range of bacterial species?

    <p>Narrow-spectrum</p> Signup and view all the answers

    What is the primary mechanism of action of tetracyclines?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    Which of the following antibiotics is characterized by higher absorption, less food interference, and less protein binding?

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

    What is the common adverse effect associated with tetracycline use in children under 12 years old?

    <p>Teeth discoloration</p> Signup and view all the answers

    What is the mechanism of action of linezolid?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    Which of the following antibiotic classes is effective against Gram-negative bacteria?

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

    What is the effect of combining β-lactam antibiotics and aminoglycosides?

    <p>Synergistic effect</p> Signup and view all the answers

    How are aminoglycosides typically administered systemically?

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

    What is the primary mechanism of action of beta-lactam antibiotics?

    <p>Inhibition of cell wall synthesis</p> Signup and view all the answers

    What is the common adverse effect of clindamycin?

    <p>Pseudomembranous colitis</p> Signup and view all the answers

    Which antibiotic is effective against protozoans such as Trichomonas vaginalis?

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

    Which medication would you prescribe to alleviate nausea and vomiting in a chemotherapy patient?

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

    What type of bacteria is Clostridium difficile?

    <p>Gram-positive</p> Signup and view all the answers

    What is the primary advantage of using aminosalicylates in patients with IBD?

    <p>Reducing the risk of developing colorectal cancer</p> Signup and view all the answers

    What is the primary mechanism of action of Ondansetron and Granisetron in alleviating nausea and vomiting?

    <p>Blocking the action of serotonin at 5-HT3 receptors</p> Signup and view all the answers

    What is the main reason aminoglycosides are reserved for severe systemic Gram-negative infections?

    <p>Potential for adverse effects such as nephrotoxicity and ototoxicity</p> Signup and view all the answers

    Which condition is characterized by a feeling of incomplete emptying?

    <p>Ulcerative colitis</p> Signup and view all the answers

    What is the mechanism of action of tetracyclines?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    What is the main precaution to be taken when using aminosalicylates in certain individuals?

    <p>All of the above</p> Signup and view all the answers

    Why is doxycycline contraindicated in pregnancy?

    <p>It is a tetracycline, which is a class D drug</p> Signup and view all the answers

    What is the mechanism of action of sulfonamides?

    <p>Inhibition of folic acid synthesis by mimicking PABA</p> Signup and view all the answers

    What is the mechanism of action of trimethoprim-sulfamethoxazole?

    <p>Inhibition of folic acid synthesis by both trimethoprim and sulfamethoxazole</p> Signup and view all the answers

    Which antibiotic targets the intermediary metabolic pathway for the synthesis of tetrahydrofolic acid?

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

    What is the mechanism of action of beta-lactams?

    <p>Inhibition of cell wall synthesis</p> Signup and view all the answers

    What is the mechanism of action of aminoglycosides?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    What is the mechanism of action of tetracyclines?

    <p>Inhibition of protein synthesis</p> Signup and view all the answers

    What is the mechanism of action of fluoroquinolones?

    <p>Inhibition of bacterial DNA gyrase and topoisomerase IV enzymes</p> Signup and view all the answers

    Which enzyme does sulfonamides inhibit by competing with}

    <p>dihydropteroate synthase</p> Signup and view all the answers

    What is the primary mechanism of action of rifamycins in bacteria?

    <p>inhibition of bacterial RNA synthesis</p> Signup and view all the answers

    What is the primary effect of corticosteroids on the immune system?

    <p>suppression of inflammatory pathways</p> Signup and view all the answers

    What is the primary use of thiopurines in the treatment of inflammatory bowel diseases?

    <p>as a steroid-sparing agent to reduce reliance on corticosteroids</p> Signup and view all the answers

    Which medication works by inhibiting ribonucleotide synthesis, leading to the induction of apoptosis in T cells?

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

    What is the primary mechanism of action of lincosamides in bacteria?

    <p>inhibition of bacterial protein synthesis</p> Signup and view all the answers

    What is the primary effect of oxazolidinones on bacterial protein synthesis?

    <p>inhibition of the initiation complex formation</p> Signup and view all the answers

    Which medication is used to treat conditions where there is excessive cell growth or immune activity, such as certain types of cancer and autoimmune diseases?

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

    What is the primary side effect of thiopurines that patients are often advised to monitor for?

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

    Which medication works by deactivating key processes in T lymphocytes?

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

    What is the primary mechanism of action of methotrexate in treating Crohn's disease?

    <p>Inhibiting cell proliferation and reducing inflammation</p> Signup and view all the answers

    What is the mechanism of action of simethicone?

    <p>Modifying the elasticity of mucus-coated gas bubbles</p> Signup and view all the answers

    Which area of the brainstem is responsible for controlling emesis?

    <p>Area postrema</p> Signup and view all the answers

    Which medication is commonly used for vestibular-related conditions such as motion sickness and BPPV?

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

    What is the mechanism of action of promethazine?

    <p>Blocking dopamine D2 receptors and histamine H1 receptors</p> Signup and view all the answers

    Which medication should be avoided in patients with Parkinson's disease?

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

    What is the effect of scopolamine on muscarinic receptors?

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

    What is the primary mechanism of action of simethicone in alleviating discomfort from excess gas?

    <p>Modifying the elasticity of mucus-coated gas bubbles</p> Signup and view all the answers

    Which medication is used to alleviate symptoms of nausea and vomiting by blocking dopamine receptors?

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

    What is the primary site of action for emesis stimulation?

    <p>Area postrema</p> Signup and view all the answers

    Study Notes

    Bacterial Keratitis

    • Caused by bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pneumoniae
    • Pseudomonas aeruginosa:
      • Infiltrate is gray in color
      • Central location of infection
      • Overlying epithelial defect, indicating damage to the outer layer of the cornea
      • Rapid progression, potentially leading to ring ulcer formation
      • Corneal perforation possible within 24-48 hours if left untreated
    • Staphylococcus aureus:
      • Infiltrate is well-defined, white-grey, or creamy in color
      • Less common to have uveitis and hypopyon compared to Streptococcus pneumoniae infections
    • Streptococcus pneumoniae:
      • Ulcer appears gray-yellow in color with a disc-like shape
      • Infections often cause severe inflammation within the eye, known as uveitis
      • Presence of hypopyon, a collection of white blood cells in the anterior chamber of the eye

    Bacterial Blepharitis

    • Caused by Staphylococcus aureus and S. epidermidis
    • Drug of choice: Bacitracin
      • Prevents the formation of bacterial cell walls, making bacteria vulnerable and killing them
      • Narrow-spectrum antibiotic, effective against gram-positive and Neisseriae
      • Can cause renal toxicity when used systemically
    • Alternative treatment: Erythromycin
      • Macrolide antibacterial
      • Inhibits bacterial protein synthesis
      • Bacteriostatic

    Meibomian Gland Dysfunction (MGD)

    • Dysfunctional meibomian glands
    • Meibomian Seborrhea: excessive production of sebum (oil) by the meibomian glands
    • Meibomianitis (or Meibomitis): inflammation of the meibomian glands
      • Can occur due to various factors

    Chlamydial Conjunctivitis

    • Caused by Chlamydia trachomatis
    • Infection presents unilaterally or bilaterally, often associated with sexually transmitted infections
    • Serotypes D to K:
      • Cause inclusion conjunctivitis, often affecting adults
    • Serotypes A, B, Ba, and C:
      • Cause trachoma, a chronic inflammatory disease of the eye
      • Predominantly affects underprivileged populations in certain regions
      • Can lead to severe complications if left untreated
      • One of the leading causes of preventable blindness worldwide
    • Stages of trachoma:
      1. Inflammation of the conjunctiva with follicle formation, mild corneal changes, and purulent discharge
      2. Increased inflammation, maturation of follicles, and possible presence of subepithelial infiltrates and limbal follicles
      3. Extension of follicles beyond the superior limbus into Herbert pits and development of conjunctival scarring (Arlt's line)
      4. Severe and advanced form with extensive scarring, absence of follicles on the upper tarsus, corneal pannus, and significant ocular complications

    External Hordeolum

    • Caused by Staphylococcus aureus
    • Presents unilaterally or bilaterally
    • Treatment: Bacitracin ointment or Polymyxin B/Bacitracin ointment
      • Effective against gram-negative organisms like Pseudomonas or Haemophilus

    Internal Hordeolum

    • Caused by Staphylococcus bacteria
    • Develops if someone already has eyelid inflammation, like blepharitis or meibomianitis
    • Left untreated may result in preseptal or orbital cellulitis
    • Treatment:
      1. Dicloxacillin:
        • Disrupts bacterial cell walls, causing them to break apart and die
        • Excreted through urine, dosage adjustments necessary for patients with low creatinine clearance
        • Adverse effects: cross-sensitivity with cephalosporins, nephrotoxicity, and serum sickness
      2. Cephalexin:
        • Bactericidal, causing defective peptidoglycan, weakening bacterial cell walls
        • Excreted through urine, dosage adjustments necessary for patients with impaired kidney function
        • Adverse effects: hypersensitivity reactions, nephrotoxicity, pseudomembranous colitis, and cross-sensitivity with penicillin
      • Alternative antibiotics for patients allergic to penicillin or cephalosporins: Macrolides### Antibiotic Mechanisms of Action
    • Tetracyclines: inhibit protein synthesis by binding to the 30S ribosomal subunit, preventing the attachment of aminoacyl-tRNA molecules and inhibiting the elongation of the polypeptide chain
      • Bacteriostatic
    • Linezolid (Oxazolidinone): inhibits bacterial protein synthesis by blocking the formation of the 70S ribosomal initiation complex
      • Bacteriostatic, but has some bactericidal activity against specific bacteria (e.g. Streptococci)
    • Macrolides (e.g. Erythromycin, Clarithromycin, Azithromycin): inhibit protein synthesis by binding to the 50S ribosomal subunit
    • Beta-lactams (e.g. Penicillins, Cephalosporins): disrupt bacterial cell wall synthesis, leading to cell death
      • Bactericidal
    • Aminoglycosides (e.g. Gentamicin, Tobramycin, Amikacin): interfere with bacterial protein synthesis
      • Bactericidal, exhibit concentration-dependent killing
    • Fluoroquinolones (e.g. Ciprofloxacin, Norfloxacin, Levofloxacin): target bacterial DNA gyrase and topoisomerase IV, disrupting DNA replication and cell division
      • Bactericidal, exhibit broad-spectrum activity
    • Metronidazole: causes damage to bacterial DNA
      • Bactericidal, effective against Protozoa (e.g. Entamoeba histolytica, Giardia lamblia, Trichomonas vaginalis)

    Antibiotic Resistance Mechanisms

    • Genetic alteration: bacteria undergo genetic changes to develop resistance
    • Transfer of drug resistance by R factors (plasmids): bacteria acquire genes encoding antibiotic resistance from other bacteria
    • Modification of target site: bacteria modify the target site of antibiotics, making them less effective
    • Decreased accumulation: bacteria reduce the accumulation of antibiotics inside their cells
    • Enzymatic inactivation: bacteria produce enzymes that chemically modify or degrade antibiotics

    Drug Combination Therapy

    • Advantages: synergism, preventing resistance, treating mixed infections
    • Disadvantages: growth-dependent effectiveness, potential interactions between antibiotics

    Other

    • Minimum Inhibitory Concentrations (MICs): the lowest concentration of an antimicrobial that inhibits the visible growth of a microorganism
    • Pulsed dosing: administering high doses of antibiotics followed by a prolonged dose-free period to achieve therapeutic concentrations and prevent toxicity
    • Narrow-spectrum antibiotics: effective against a single or limited group of organisms
    • Broad-spectrum antibiotics: effective against a wide range of microbial species
    • Extended-spectrum antibiotics: effective against a wide range of bacteria, including both Gram-positive and Gram-negative species### Antibiotics and Bacterial Infections
    • Aminoglycosides are not administered orally due to poor gastrointestinal absorption. Instead, they are given intravenously or intramuscularly.
    • Aminoglycosides are reserved for severe systemic Gram-negative infections due to their potential for adverse effects such as nephrotoxicity and ototoxicity.
    • The mechanism of action of tetracyclines involves the inhibition of protein synthesis by binding to the 30S ribosomal subunit, preventing the initiation of translation.

    Sulfonamides and Folic Acid Synthesis

    • Sulfonamides inhibit bacterial folic acid synthesis by competing with para-aminobenzoic acid (PABA), which is necessary for folic acid production.
    • Trimethoprim inhibits dihydrofolate reductase, disrupting folic acid synthesis.
    • Trimethoprim/Sulfamethoxazole (Bactrim) is used to treat a wide range of bacterial infections, including ear infections, urinary tract infections, bronchitis, and Pneumocystis jirovecii pneumonia.

    Antibiotic Mechanisms of Action

    • Beta-Lactams: Inhibit bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs).
    • Aminoglycosides: Bind to the 30S ribosomal subunit, causing misreading of mRNA and inhibiting protein synthesis.
    • Tetracyclines: Bind to the 30S ribosomal subunit, inhibiting protein synthesis by preventing the attachment of aminoacyl-tRNA to the mRNA-ribosome complex.
    • Glycopeptides: Inhibit bacterial cell wall synthesis by binding to the (D-alanyl-D-alanine) peptide side chain.
    • Macrolides: Bind to the 50S ribosomal subunit, inhibiting bacterial protein synthesis by blocking the translocation step during translation.
    • Fluoroquinolones: Inhibit bacterial DNA gyrase and topoisomerase IV enzymes, essential for DNA replication, repair, and transcription.
    • Sulfonamides: Inhibit bacterial folic acid synthesis by competitively inhibiting dihydropteroate synthase.
    • Oxazolidinones: Bind to the 50S ribosomal subunit, preventing the formation of the initiation complex for protein synthesis.
    • Lincosamides: Bind to the 50S ribosomal subunit, inhibiting protein synthesis by blocking the translocation step during translation.
    • Rifamycins: Inhibit bacterial RNA synthesis by binding to the bacterial RNA polymerase.

    Corticosteroids

    • Mechanism of action: Decrease production of inflammatory molecules, suppress metabolism of arachidonic acid, induce apoptosis in certain immune cells, and promote production of anti-inflammatory proteins.
    • Use: Manage inflammatory bowel diseases (IBD) like Crohn's disease and ulcerative colitis, reduce inflammation in the digestive tract.

    Thiopurines

    • Mechanism of action: Inhibit ribonucleotide synthesis, leading to apoptosis in T cells.
    • Use: Treat active and chronic inflammatory conditions, particularly as steroid-sparing agents to reduce reliance on corticosteroids.

    Methotrexate

    • Mechanism of action: Inhibits dihydrofolate reductase, disrupting DNA and RNA synthesis.
    • Use: Treat conditions with excessive cell growth or immune activity, such as certain types of cancer and autoimmune diseases like rheumatoid arthritis.

    Simethicone

    • Mechanism of action: Modifies the elasticity of mucus-coated gas bubbles, causing them to collapse and reducing gas accumulation.
    • Use: Relieve discomfort from excess gas in the digestive tract.

    Emesis (Vomiting)

    • Pathophysiology: Controlled by the area postrema in the brainstem, which can be stimulated by signals from the stomach and gastrointestinal tract, vestibular system, and cortex and thalamus.
    • Medications:
      • Scopolamine: Blocks muscarinic M1 receptors, used to treat vestibular-related conditions like motion sickness and benign paroxysmal positional vertigo (BPPV).
      • Promethazine: Acts as a dopamine D2 receptor antagonist and histamine H1 blocker, used to treat nausea and vomiting.

    Adrenergic Agonists and Antagonists

    • Epinephrine: Stimulates alpha and beta receptors, causing effects like increased heart rate, vasopressor response, and bronchodilation.
    • Norepinephrine: Stimulates alpha receptors, causing vasoconstriction and increased blood pressure.
    • Isoproterenol: Stimulates beta-1 and beta-2 receptors, causing increased heart rate and bronchodilation.
    • Dopamine: Stimulates alpha-1 and beta-1 receptors, causing increased heart rate and vasopressor response.

    Cholinergic System

    • Muscarinic receptors: Found in the neuro-effector junction of the parasympathetic nervous system, heart, smooth muscle, and brain.
    • Nicotinic receptors: Found in the neuro-effector junction of the parasympathetic nervous system, skeletal muscle, and brain.
    • Acetylcholine: Released by the parasympathetic nervous system, causes muscarinic and nicotinic effects.
    • Bethanechol: Stimulates muscarinic receptors, used to promote urination.
    • Carbachol: Exhibits both muscarinic and nicotinic actions.
    • Pilocarpine: Stimulates muscarinic receptors, used to treat open-angle glaucoma.

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    Learn about the autonomic nervous system, its division, and how it controls the body's involuntary activities. Understand the structure of the autonomic nervous system, including the two-neuron chain. Test your knowledge of the peripheral nervous system!

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