Sensitivity of a nerve fibre to blockade by lignocaine
depends on:
A. Whether the fibre is sensory or motor
B. Whether the fibre is myelinated or nonmyelinated
C. Internodal distances in the fibre
D. Both ‘B’ and ‘C’ are correct

1 Answer

Answer :

D. Both ‘B’ and ‘C’ are correct

Related questions

Description : Which of the following is not the reason for greater susceptibility of smaller sensory fibres to blockade by local anaesthetics than larger motor fibres: A. Sensory fibres are inherently ... higher frequency longer lasting action potential D. Smaller fibres have shorter critical lengths for blockade

Last Answer : A. Sensory fibres are inherently more sensitive than motor fibres

Description : A resting nerve is relatively resistant to blockade by lignocaine compared to one which is repeatedly stimulated because: A. Lignocaine penetrates resting nerve membrane poorly B. Lignocaine binds ... promotes ionization of lignocaine D. Nodes of Ranvier are inaccessible in the resting state

Last Answer : B. Lignocaine binds more avidly to the inactivated Na+ chan

Description : Epidural anaesthesia differs from spinal anaesthesia in that: A. Epidural anaesthesia produces less cardiovascular complications B. Headache is more common after epidural anaesthesia C. Blood ... . Greater separation between sensory and motor blockade can be obtained with epidural anaesthes

Last Answer : D. Greater separation between sensory and motor blockade can be obtained with epidural anaesthesia

Description : yocardial Na+ channel blockade by lignocaine has the following characteristic: A. It blocks inactivated Na+ channels more than activated channels B. It blocks activated Na+ channels more than inactivated ... Na+ channels D. It produces more prominent blockade of atrial than ventricular Na+ channels

Last Answer : A. It blocks inactivated Na+ channels more than activated channels

Description : Low concentration of bupivacaine is preferred for spinal / epidural obstetric analgesia because: A. It has a longer duration of action B. It can produce sensory blockade without paralysing abdominal muscles C. ... in maternal tissues so that less reaches the foetus D. All of the above are correct

Last Answer : D. All of the above are correct

Description : Can a nerve fibre and nerve both carry sensory and motor impulses?

Last Answer : There are the Mixed Nerves in the spinal column that carry bothsensory and motor nerves, but these neurons have 2 different jobsthat they do,& I know of no neurons doing both as the impulsestravel to 2 different locations which couldn't be done at the sametime.

Description : What is the difference between impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre? -Biology

Last Answer : answer:

Description : Which of the following statements is true for lignocaine: A. It is an ester-linked local anaesthetic B. It is not likely to exhibit cross-sensitivity with procaine C. It has a shorter duration of action than procaine D. It is not a surface anaesthetic

Last Answer : B. It is not likely to exhibit cross-sensitivity with procaine

Description : Dantrolene sodium reduces skeletal muscle tone by: A. Reducing acetylcholine release from motor nerve endings B. Suppressing spinal polysynaptic reflexes C. Inhibiting the generation of muscle action potential D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre

Last Answer : D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre

Description : The site of action of d-tubocurarine is: A. Spinal internuncial neurone B. Motor nerve ending C. Muscle end-plate D. Sodium channels in the muscle fibre

Last Answer : C. Muscle end-plate

Description : Initial bradycardia caused by intramuscular injection of atropine is believed to be caused by: A. Stimulation of medullary vagal centre B. Stimulation of vagal ganglia C. Blockade of M2 receptors on SA nodal cells D. Blockade of muscarinic autoreceptors on vagal nerve endings

Last Answer : D. Blockade of muscarinic autoreceptors on vagal nerve endings

Description : Initial bradycardia caused by intramuscular injection of atropine is believed to be caused by: A. Stimulation of medullary vagal centre B. Stimulation of vagal ganglia C. Blockade of M2 receptors on SA nodal cells D. Blockade of muscarinic autoreceptors on vagal nerve endings

Last Answer : D. Blockade of muscarinic autoreceptors on vagal nerve endings

Description : Started within 4-6 hours of acute myocardial infarction, which of the following drug(s) can reduce the area of necrosis and the attendant mortality: A. Propranolol B. Glyceryl trinitrate C. Lignocaine D. Both ‘A’ and ‘B’ are correct

Last Answer : D. Both ‘A’ and ‘B’ are correct

Description : Lignocaine is the preferred antiarrhythmic for emergency control of cardiac arrhythmias following acute myocardial infarction because: A. It has a rapidly developing and titratable antiarrhythmic action B. It causes ... atrial as well as ventricular arrhythmias D. Both A' and B' are correct

Last Answer : D. Both ‘A’ and ‘B’ are correct

Description : Neostigmine reverses the following actions of d-tubocurarine except: A. Motor weakness B. Ganglionic blockade C. Histamine release D. Respiratory paralysis

Last Answer : C. Histamine release

Description : The following is an orally active lignocaine congener used for both acute as well as chronic ventricular arrhythmias: A. Mexiletine B. Flecainide C. Moricizine D. Propafenone

Last Answer : A. Mexiletine

Description : The antiarrhythmic drug which decreases both rate of depolarization (phase 0) as well as rate of repolarization (phase 3) of myocardial fibres is: A. Lignocaine B. Propranolol C. Quinidine D. Verapamil

Last Answer : C. Quinidine

Description : In spinal anaesthesia the segmental level of: A. Sympathetic block is lower than the sensory block B. Sympathetic block is higher than the sensory block C. Motor block is higher than the sensory block D. Sympathetic, motor and sensory block has the same level

Last Answer : B. Sympathetic block is higher than the sensory block

Description : Myelinated and unmyelinated nerve fibres are found in PNS respectively are

Last Answer : Myelinated and unmyelinated nerve fibres are found in PNS respectively are

Description : Myelinated and unmyelinated nerve fibres are found in PNS respectively are

Last Answer : Myelinated and unmyelinated nerve fibres are found in PNS respectively are

Description : Compared with myelinated nerve fibres, non-myelinated nerve fibres : a. have a higher threshold for stimulation b. have a longer refractory period c. transmit impulses at a lower frequency d. all above

Last Answer : all above

Description : Which one of the following contains the largest quantity of extracellular material? (a) Striated muscle (b) Areolar tissue (c) Stratified epithelium (d) Myelinated nerve fibres

Last Answer : (b) Areolar tissue

Description : In injury of the peripheral nerve: a. pure sensory or pure motor nerve tends to regenerate better than mixed nerve b. in neuropraxia, there is anatomical disruption of the nerve c. Wallerian ... occurs 3 days after the injury d. Wallerian degeneration occurs proximal to the site of the injury

Last Answer : pure sensory or pure motor nerve tends to regenerate better than mixed nerve

Description : In injury of the peripheral nerve: a. pure sensory or pure motor nerve tends to regenerate better than mixed nerve b. in neuropraxia, there is anatomical disruption of the nerve c. Wallerian ... occurs 3 days after the injury d. Wallerian degeneration occurs proximal to the site of the injury

Last Answer : pure sensory or pure motor nerve tends to regenerate better than mixed nerve

Description : The ciliary ganglion: a. is found between the optic nerve and the medial rectus b. contains sympathetic nerve that supplies the sphincter pupillae c. is a parasympathetic relay ganglion for fibers from ... nucleus d. contains sensory nerve e. has a motor nerve that goes to the inferior oblique

Last Answer : is a parasympathetic relay ganglion for fibers from the Edinger-Westphal nucleus

Description : Which nerve is assessed when the nurse asks the patient to dorsiflex the ankle and extend the toes? a) Peroneal The motor function of the peroneal nerve is assessed by asking the patient to ... the patient to spread all fingers allows the nurse to assess motor function affected by ulnar innervation.

Last Answer : a) Peroneal The motor function of the peroneal nerve is assessed by asking the patient to dorsiflex the ankle and extend the toes while the sensory function is assessed by pricking the skin between the great and center toes.

Description : Which nerve is assessed when the nurse asks the patient to spread all fingers? a) Ulnar Asking the patient to spread all fingers allows the nurse to assess motor function affected by ulnar innervation ... The median nerve is assessed by asking the patient to touch the thumb to the little finger.

Last Answer : a) Ulnar Asking the patient to spread all fingers allows the nurse to assess motor function affected by ulnar innervation while pricking the fat pad at the top of the small finger allows assessment of the sensory function affected by the ulnar nerve.

Description : Which of the following drugs depresses automaticity of SA node as well as ectopic foci, abbreviates action potential duration of Purkinje fibres, and slows atrioventricular conduction: A. Propranolol B. Lignocaine C. Procainamide D. Bretylium

Last Answer : A. Propranolol

Description : Select the drug which is used by intravenous infusion for emergency control of tachycardia and sudden rise in blood pressure: A. Amiodarone B. Lignocaine C. Esmolol D. Disopyramide

Last Answer : C. Esmolo

Description : The most significant feature of the antiarrhythmic action of lignocaine is: A. Suppression of phase-4 depolarization in ventricular ectopic foci B. Prolongation of action potential duration C. Prolongation of effective refractory period D. Depression of membrane responsiveness

Last Answer : A. Suppression of phase-4 depolarization in ventricular ectopic foci

Description : The following is true of procainamide except: A. It generates an active metabolite in the body B. Its plasma half-life is longer than that of quinidine C. On long-term use, it ... erythematosus like illness D. It is effective in many cases of ventricular extrasystoles, not responding to lignocaine

Last Answer : A. Disopyramide

Description : The following antiarrhythmic drug has the most prominent anticholinergic action: A. Disopyramide B. Quinidine C. Procainamide D. Lignocaine

Last Answer : A. Disopyramide

Description : Select the most suitable antiarrhythmic drug for counteracting ventricular extrasystoles due to digoxin toxicity: A. Lignocaine B. Quinidine C. Verapamil D. Amiodarone

Last Answer : A. Lignocaine

Description : The local anaesthetic having high cardiotoxic and arrhythmogenic potential is: A. Lignocaine B. Procaine C. Bupivacaine D. Ropivacaine

Last Answer : C. Bupivacaine

Description : Which of the following is a poor surface anaesthetic: A. Procaine B. Lignocaine C. Tetracaine D. Benoxinate

Last Answer : A. Procaine

Description : The following local anaesthetic raises BP instead of tending to cause a fall: A. Cocaine B. Dibucaine C. Lignocaine D. Procaine

Last Answer : A. Cocaine

Description : Blockade of both dopamine D2 and serotonin 5-HT2A/2C receptors is a distinctive feature of: A. Pimozide B. Haloperidol C. Ketanserin D. Clozapine

Last Answer : D. Clozapine

Description : Anthelmintic action of piperazine is due to: A. Interference with ATP generation in the worm B. Blockade of glucose uptake by the worm C. Hyperpolarization of nematode muscle by GABA agonistic action D. Depolarization of nematode muscle by activating nicotinic receptors

Last Answer : C. Hyperpolarization of nematode muscle by GABA agonistic action

Description : Frequency dependent cardiac calcium channel blockade is exhibited by: A. Verapamil B. Nifedipine C. Felodipine D. Amlodipin

Last Answer : A. Verapamil

Description : The following is not true of quinidine: A. It blocks myocardial Na+ channels primarily in the open state B. It has no effect on myocardial K+ channels C. It produces frequency dependent blockade of myocardial Na+ channels D. It delays recovery of myocardial Na+ channels

Last Answer : B. It has no effect on myocardial K+ channels

Description : The principal action common to all class I antiarrhythmic drugs is: A. Na+ channel blockade B. K+ channel opening C. Depression of impulse conduction D. Prolongation of effective refractory period

Last Answer : A. Na+ channel blockade

Description : Select the opioid antagonist that is preferred for long term opioid blockade therapy of post addicts: A. Nalorphine B. Naloxone C. Naltrexone D. Nalbuphine

Last Answer : C. Naltrexone

Description : Adaptive changes in brain monoamine turnover due to blockade of noradrenaline/5-HT reuptake is credited with the following effect: A. Antipsychotic B. Antianxiety C. Antiparkinsonian D. Antidepressant

Last Answer : D. Antidepressant

Description : The GABAB receptor: A. Is an intrinsic ion channel containing receptor B. Mediates neuronal depolarization C. Is insensitive to blockade by bicuculline D. Regulates intracellular cAMP

Last Answer : C. Is insensitive to blockade by bicuculline

Description : The following antibiotic accentuates the nuromuscular blockade produced by pancuronium: A. Streptomycin B. Erythromycin C. Penicillin G D. Chloramphenicol

Last Answer : A. Streptomycin

Description : The fall in blood pressure caused by d-tubocurarine is due to: A. Reduced venous return B. Ganglionic blockade C. Histamine release D. All of the above

Last Answer : D. All of the above

Description : The purpose/purposes served by the progestin component of the combined estrogen + progestin contraceptive pill is/are: A. Suppression of ovulation B. Prompt bleeding at the end of the course C. Blockade of increased risk of endometrial carcinoma D. All of the above

Last Answer : D. All of the above