Anesthetics Overview Quiz

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Questions and Answers

What effect does the increase of local anesthetics (LA) have on action potentials (AP)?

Increases the rate of rise of AP

Has no effect on action potentials

Decreases the rate of rise of AP (correct)

Increases the maximum depolarization

How does binding of local anesthetic (LA) affect the inactivation state of sodium channels?

It makes the inactivated state reversible

It prolongs the inactivated state (correct)

It shortens the duration of the inactivated state

It has no effect on the inactivated state

What is the effect of local anesthetics on the refractory period of nerve fibers?

It decreases the refractory period

It increases the refractory period (correct)

It has no effect on the refractory period

It stabilizes the refractory period without changes

What is the primary form of local anesthetic that binds to the receptor in sodium channels?

Cationic form Signup and view all the answers

Which state of the sodium channel has a higher affinity for local anesthetics?

Activated state Signup and view all the answers

How does local anesthetics affect the channel recovery process?

Delays channel recovery to resting state Signup and view all the answers

What role does the activation gate play in sodium channel function?

It opens to allow Na+ ions to enter during depolarization Signup and view all the answers

What occurs during the depolarization phase of an action potential?

Sodium channels open and allow Na+ influx Signup and view all the answers

What is the last area of the brain to be affected by increasing depth of anaesthesia?

The vital centers in the medulla Signup and view all the answers

Which of the following agents directly activates Cl channels, according to the content?

Barbiturates Signup and view all the answers

What effect does the stage of analgesia have on the patient?

Pain is progressively abolished while the patient remains conscious Signup and view all the answers

Which neurotransmitter's action is augmented by barbiturates and inhalational anaesthetics in the spinal cord?

Glycine Signup and view all the answers

What was the primary classification method for anaesthesia stages described by Guedel?

Four stages, with the third stage further divided into planes Signup and view all the answers

What role do inhaled anaesthetics and barbiturates play in anaesthesia?

They potentiate the action of inhibitory transmitters Signup and view all the answers

What happens to responsiveness to painful stimuli in the anaesthetic state?

It becomes completely abolished, resulting in immobility Signup and view all the answers

What is a key feature of the stage of analgesia during anaesthesia?

Amnesia develops by the end of the stage Signup and view all the answers

What is the role of the S4 segments in the function of the subunit?

They move vertically on depolarization and help open the activation gate. Signup and view all the answers

Which statement correctly describes the function of local anesthetics (LAs) in nerve conduction?

They do not alter the resting membrane potential. Signup and view all the answers

What happens to the LA receptor located in the S6 segment when the nerve is repeatedly stimulated?

It transforms to a higher affinity conformation or becomes exposed. Signup and view all the answers

How does the pKa of local anesthetics affect their onset time of blockade?

Lower pKa correlates with quicker onset. Signup and view all the answers

What distinguishes chloroprocaine from other local anesthetics despite having a high pKa?

It has a rapid onset of action. Signup and view all the answers

What effect does exposure to higher concentrations of Ca2+ have on sodium channel inactivation?

It reduces the inactivation of sodium channels. Signup and view all the answers

What forms the wall of the Na selective pore in the subunit?

S5-S6 segments from all four domains. Signup and view all the answers

Which local anesthetics are classified as slow-acting due to their pKa and ionization properties?

Bupivacaine and tetracaine. Signup and view all the answers

What is the primary concern with the use of halothane in susceptible individuals?

Risk of liver damage and hepatitis Signup and view all the answers

What concentration of halothane is typically used for maintenance during anaesthesia?

0.5-1% Signup and view all the answers

Which property of halothane makes it a preferred anaesthetic for asthmatics?

Nonirritant and sweet odour Signup and view all the answers

How does halothane affect urine formation during anaesthesia?

Decreases urine formation Signup and view all the answers

What is a notable disadvantage of using halothane during labor?

It can prolong delivery Signup and view all the answers

What is the solubility level of halothane in blood?

Moderate solubility Signup and view all the answers

What type of anaesthetic is halothane classified as?

Volatile liquid Signup and view all the answers

Which of the following is true about halothane's analgesic properties?

It is not a good analgesic. Signup and view all the answers

What happens to gases with higher lipid solubility during anaesthesia?

They continue to enter adipose tissue for hours. Signup and view all the answers

How does carbon dioxide affect cerebral blood flow during anaesthesia?

It causes cerebral vasodilation. Signup and view all the answers

What effect does the discontinuation of nitrous oxide have after prolonged anaesthesia?

It causes diffusion hypoxia. Signup and view all the answers

What prevents diffusion hypoxia after discontinuing nitrous oxide?

Continuing 100% oxygen inhalation. Signup and view all the answers

In what manner are inhaled anaesthetics primarily eliminated from the body?

Elimination is mainly through the lungs. Signup and view all the answers

What is a characteristic feature of diffusion hypoxia?

It can be dangerous if cardiopulmonary reserve is low. Signup and view all the answers

Which statement is true regarding the solubility of anaesthetics in tissues?

Gases are equally soluble in lean tissues and blood. Signup and view all the answers

What phenomenon is referred to as the 'second gas effect'?

The faster induction when a second anaesthetic is given simultaneously. Signup and view all the answers

Study Notes

Local Anesthetics

LA affects sodium channels in nerve fibers
LA binding prolongs the inactivated state of the sodium channel, increasing the refractory period
LA blockade is frequency-dependent, meaning it increases with higher stimulation frequencies
LA blockade is not due to hyperpolarization, resting membrane potential is unaffected
LA onset times depend on pKa; lower pKa LAs have faster onset
LA acts on sensory nerve endings, nerve trunks, neuromuscular junctions, and ganglia

General Anesthetics

General anesthesia (GA) acts on the brain, suppressing the higher functions first
GA affects vital centers in the medulla last
GA induction and recovery depend on concentration of the anesthetic in the brain
GA uptake, distribution, and elimination depend on solubility in blood and tissues
GA concentration in fat tissue is higher than in other tissues due to higher lipid solubility
GA affects cerebral blood flow; increased carbon dioxide inhalation causes cerebral vasodilation, accelerating induction and recovery
GA elimination is primarily through the lungs, and recovery also depends on the same factors that determined induction.

Halothane

Halothane is a potent volatile liquid anesthetic with sweet odor, non-irritant and non-flammable
Halothane is a moderate blood solubility, making induction reasonably quick and pleasant
Halothane is not a good analgesic or muscle relaxant, but potentiates competitive neuromuscular blockers
Halothane causes bronchodilation, making it a preferred anesthetic for asthmatics
Halothane inhibits intestinal and uterine contractions
Halothane can prolong delivery during labor and increase postpartum blood loss
Halothane decreases urine formation due to low glomerular filtration rate (GFR) caused by a decrease in blood pressure
Halothane is a rare cause of hepatitis, particularly after repeated use or in those with familial predisposition
Halothane can cause malignant hyperthermia, a genetically determined reaction, which occurs rarely
Halothane toxicity is less frequent in children

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Description

Test your knowledge on local and general anesthetics with this quiz. Explore how local anesthetics interact with sodium channels and the mechanisms of general anesthetics in the brain. Enhance your understanding of pharmacology related to anesthetics.