The biochemical mechanism of action of digitalis is associated with (a) A decrease in calcium uptake by the sarcoplasmic reticulum (b) An increase in ATP synthesis (c) A modification of the actin molecule (d) An increase in systolic intracellular calcium levels (e) A block of sodium/calcium exchange

1 Answer

Answer :

Ans: D

Related questions

Description : Characteristics of Vitamin D and its metabolites include which one of the following? (a) Act to decrease serum levels of calcium (b) Activation of their Vitamin D receptors increases cellular CAMP ... Vitamin D increase renal excretion of calcium (e) Vitamin D deficiency results in Pager's disease

Last Answer : Ans: C

Description : a2–adrenergic receptors are associated with following except (a) Increase in phospholipase C activity (b) Increase in potassium channel conductance (c) Decrease in calcium channel conductance (d) Increase in adenylyl cyclase activity

Last Answer : Ans: D

Description : The sequence of events in muscle contraction a. action potential depolarise the T-tubules b. depolarisation of T-tubules release calcium from sarcoplasmic reticulum c. calcium binds to the troponin-tropomycin complex d. all above

Last Answer : all above

Description : Cromolyn has as its major action (a) Block of calcium channels in lymphocytes (b) Block of mediator release from mast cells (c) Block of phosphodiesterase in mast cells and basophils (d) Smooth muscle relaxation in the bronchi (e) Stimulation of cortisol release by the adrenals

Last Answer : Ans: B

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 : Action of norepinephrine and epinephrine are terminated by (a) Reuptake into nerve terminal (b) Dilution by diffusion and uptake at extraneuronal site (c) Metabolic transformation (d) All of the above

Last Answer : Ans: D

Description : The most probable mechanism of action of mebendazole is: A. Depolarization of membrane and spastic paralysis of the worm B. Hyperpolarization of membrane and flaccid paralysis of the worm C. Loss of ... inhibition of glucose uptake in the worm D. Tegument damage and leakage of contents of the worm

Last Answer : C. Loss of intracellular microtubules and inhibition of glucose uptake in the worm

Description : Drugs that block the a receptor on effector cells at adrenergic nerve endings (a) Antagonize the effects of isoproterenol on the heart rate (b) Antagonize some of the effects of epinephrine on ... the effects of epinephrine on adenylyl cyclase (d) Cause mydriasis (e) Decreases blood glucose levels

Last Answer : Ans: B

Description : Which of the following best describes the mechanism of action of scopolamine ? (a) Irreversible antagonist at nicotinic receptors (b) Irreversible antagonist at muscarinic receptors (c) ... receptors (d) Reversible antagonist at muscarinic receptors (e) Reversible antagonist at nicotinic receptors

Last Answer : Ans: D

Description : Which of the following is an orally active drug that blocks sodium channels and decreases action potential duration? (a) Adenosine (b) Amiodarone (c) Disopyramide (d) Esmolol (e) Mexiletine

Last Answer : Ans: E

Description : Which of the following statement(s) is/are true concerning ischemia reperfusion injury? a. During ischemia, ATP degradation results in increased plasma and intracellular levels of ... immunization with antibodies to neutrophil adhesive complex lessen the ischemic/reperfusion microvascular injury

Last Answer : Answer: a, b, c, d During the ischemia and hypoperfusion phase, degradation of ATP stores essential to maintain cell integrity and significant loss of diffusible ... either the neutrophil adhesive complex or the endothelial selectins dramatically lessens ischemia/reperfusion microvascular injury

Description : Propranolol does not block the following action of adrenaline (a) Bronchodilation (b) Lipolysis (c) Muscle tremor (d) Mydriasis

Last Answer : Ans: D

Description : The action of digitalis is enhanced by (a) Sodium (b) Calcium (c) Magnesium (d) Potassium (e) Chloride

Last Answer : Ans: B

Description : Denervation super-sensitivity includes (a) Proliferation of receptors (b) Loss of mechanism for transmitter removal (c) Increased post-junctional responsiveness (d) All of the above

Last Answer : Ans: D

Description : Typical results of beta-receptor activation include which one of the following? (a) Hypoglycemia (b) Lipolysis (c) Glycogen synthesis (d) Decreased skeletal muscle tremor (e) Decreased rennin secretion

Last Answer : Ans: B

Description : A patient has been taking digoxin for several years for chronic heart failure is about to receive atropine for another condition. A common effect of digoxin (at therapeutic blood levels) that can ... Increased atrial contractility (c) Increased PR interval on the ECG (d) Headaches (e) Tachycardia

Last Answer : Ans: C

Description : The felderstrukter fibres of the extraocular musclea. form the bulk of the orbital part of the muscle b. have poorly developed sarcoplasmic reticulum c. are singly innervated d. are more richly supplied by blood than the fibrillenstrukter fibres

Last Answer : have poorly developed sarcoplasmic reticulum

Description : The antianginal effect of propranolol may be attributed to which one of the following (a) Block of exercise – induced tachycardia (b) Decreased end – diastolic ventricular volume (c) Dilation of consticted coronary vessels (d) Increased cardiac force (e) Increased resting heart rate

Last Answer : Ans: A

Description : Propranolol is useful in all of the following except (a) Angina (b) Familial tremor (c) Hypertension (d) Idiopathic hypertrophic subaortic cardiomyopathy (e) Partial atrioverntricular heart block

Last Answer : Ans: E

Description : Phenylephrine (a) Mimics the transmitter at post-synaptic receptors (b) Displaces transmitter from axonal terminal (c) Inhibits synthesis of transmitter (d) None of the above

Last Answer : Ans: A

Description : Guanethidine inhibits (a) Synthesis of transmitter (b) Metabolism of transmitter (c) Release of transmitter (d) Displacement of transmitter from axonal terminal

Last Answer : Ans: C

Description : The most efficacious inhibitor of catecholamine synthesis in the body is (a) a - methyl – p - tyrosine (b) a - methyldopa (c) a - methyl - norepinephrine (d) Pyrogallol

Last Answer : Ans: A

Description : Following enzyme is involved in the synthesis of actylcholine (a) Choline acetyl transferase (b) Acetyl cholinesterase (c) Both (a) and (b) (d) None of the above

Last Answer : Ans: A

Description : Reserprine, an alkaloid derived from the root of Rauwolfia serpentina (a) Can be used to control hyperglycemia (b) Can cause severe depression of mood (c) Can decrease gastrointestinal secretion and motility (d) Has no cardiac effects (e) A spare receptor agonist

Last Answer : Ans: B

Description : Choose the correct statement about use of βadrenergic blockers in CHF: A. All β blockers are equally effective in CHF B. They are used as alternative to conventional therapy with ... dysfunction due to dilated cardiomyopathy D. They are indicated only in asymptomatic left ventricular dysfunction

Last Answer : C. They are most useful in mild to moderate cases with systolic dysfunction due to dilated cardiomyopathy

Description : Intracellular organelles involved with protein synthesis include: a. Mitochondria b. Endoplasmic reticulum c. Golgi complex d. Lysosomes

Last Answer : Answer: b, c Mitochondria are the major source of energy production in eukaryotic cells. The endoplasmic reticulum is the network of interconnected membranes forming closed vesicles, ... containing acid hydrolytic enzymes that degrade polymers such as proteins, carbohydrates, and nucleic acids

Description : The electrophysiological effects of digitalis on Purkinje fibres include the following except: A. Enhancement of resting membrane potential B. Decrease in the slope of phase-0 depolarization C. Increase in the rate of phase-4 depolarization D. Abbreviation of action potential duration

Last Answer : A. Enhancement of resting membrane potential

Description : Which one of the following is characteristic of captopril and enalapril ? (a) Competitively blocks angiotensim II at its receptor (b) Decreases angiotensin II concentration in the blood (c) Decreases ... and decreases potassium in the blood (e) Decreases sodium and increases potassium in the urine

Last Answer : Ans: B

Description : A 70-year-old man has severe urinary hesitancy associated with benign prostatic hyperplasia. He has tried alpha blockers with little relief. His physician recommends a drug that blocks 5a - reductase in ... prescription for (a) Atropine (b) Clonidine (c) Hydralazine (d) Neostigmine (e) Propranolol

Last Answer : Ans: B

Description : Which one of the following drugs, when used chronically, is associated with the development of bone pain and mineralization defects such as osteomalacia? (a) Calcitonin (b) Dihydrotachysterol (c) Ergocalciferol (d) Etidronate (e) Norgestrel

Last Answer : Ans: D

Description : A friend has very severe hypertension and asks about a drug her doctor wishes to prescribe. Her physician has explained that this drug is associated with tachycardia and fluid retention (which may be marked ... has described? (a) Captopril (b) Guanethidine (c) Minoxidil (d) Prazosin (e) Propranolol

Last Answer : Ans: C

Description : Which of the following drugs is the drug of choice in anaphylaxis associated with bronchospasm and hypotension ? (a) Cortisone (b) Epinephrine (c) Isoproterenol (d) Norepinephrine (e) Phenylephrine

Last Answer : Ans: B

Description : The effects of glucocorticoid hormones include: a. increase hepatic glycogen synthesis b. decrease glucose uptake by the adipose tissue c. decrease hepatic gluconeogesis d. increase protein synthesis in the skeletal muscles

Last Answer : . increase hepatic glycogen synthesis

Description : When used as an antiarrhythmic drug, Lidocaine typically (a) Increases action potential duration (b) Increases contractility (c) Increses PR interval (d) Reduces abnormal automaticity (e) Reduces resting potential

Last Answer : Ans: D

Description : Propanolol can be used to allay anxiety associated with (a) Chronic neurotic disorer (b) Schizopherenia (c) Short-term stressful situation (d) Endogenous depression

Last Answer : Ans: C

Description : Ephedrine is similar to adrenaline in the following feature (a) Potency (b) Inability to penetrate blood-brain barrier (c) Duration of action (d) Producing both a and ß adrenergic effects

Last Answer : Ans: D

Description : Which of the following mydriatics has the fastest and briefest action ? (a) Atropine (b) Homatropine (c) Tropicamide (d) Cyclopentolate

Last Answer : Ans: C

Description : Glycopyrrolate is the preferred antimuscannic drug for use before and during surgery because (a) It is potent and fast acting (b) It has no central action (c) It has antisecretory and vagolytic actions (d) All of the above

Last Answer : Ans: D

Description : Recognized adverse effects of quinidine include which one of the following? (a) Cinchonism (b) Constipation (c) Lupus erythematosus (d) Increase in digoxin clearance (e) Precipitation of hyperthyroidism

Last Answer : Ans: A

Description : Which of the following effects of epinephrine would be blocked by phentolamine but not by metoprolol ? (a) Cardiac stimulation (b) Contractionof radial smooth muscle in the iris (c) Increase of camp in fat (d) Relaxation of bronchial smooth muscle (e) Relaxation of the uterus

Last Answer : Ans: B

Description : The neurotransmitter agent that is normally released in the sinoatrial node of the heart in response to a blood pressure increase is (a) Acetylcholine (b) Dopamine (c) Epinephrine (d) Glutamate (e) Norepinephrine

Last Answer : Ans: A

Description : Which of the following statement(s) is/are true concerning the microvascular and cellular response to shock? a. Osmodically induced mobilization of intracellular fluid is the initial ... d. Abnormal intracellular calcium homeostasis may contribute to the cellular dysfunction of shock

Last Answer : Answer: c, d Moderate hypovolemia results in a relatively rapid spontaneous restitution of intravascular volume through expansion of the plasma space. This plasma expansion by ... potassium pump. Cellular dysfunction also appears to be related to abnormal intracellular calcium homeostasis

Description : Select the alternative giving correct identification and function of the organelle A' in the diagram. (a) Mitochondria - Produce cellular energy in the form of ATP (b) Golgi body - ... packaging material (c) Lysosomes - Secrete hydrolytic enzymes (d) Endoplasmic reticulum - Synthesis of lipids

Last Answer : (a) Mitochondria - Produce cellular energy in the form of ATP

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 : The most probable mechanism of action of imidazole antifungal drugs is: A. They bind to ergosterol in fungal cell membrane and make it leaky B. They interfere with ergosterol synthesis by fungi C. They interfere with fungal mitosis D. They block oxidative phosphorylation in fungi

Last Answer : B. They interfere with ergosterol synthesis by fungi

Description : Acetyl CoA carboxylase regulates fatty acid synthesis by which of the following mechanism? (A) Allosteric regulation (B) Covalent modification (C) Induction and repression (D) All of these

Last Answer : Answer : D

Description : Most hormone receptors are localized on the cell membrane and transduce hormone binding into altered levels of intracellular messengers. A limited number of intracellular receptors do exist. Which of ... protein serves as an inhibitor protein blocking the DNA-binding domain of the steroid receptor

Last Answer : Answer: a, d Although most hormone and other messenger receptors are extracellular, intracellular receptors have been identified. The hormone messengers involved for these receptors are primarily ... DNA-binding domain of the receptor. Activation involves the dissociation of the inhibitor protein

Description : Which of the following represents the action of insulin? (a) Increases blood glucose level by stimulating glucagon production. (b) Decreases blood glucose levels by forming glycogen. (c) ... promoting cellular uptake of glucose. (d) Increases blood glucose levels by hydrolysis of glycogen.

Last Answer : (b) Decreases blood glucose levels by forming glycogen