WREB Written Board questions and answers rated A+

WREB Written BoardNerve Function: Messages are electrical action potentials called - correct answer impulses SAME- Sensory = __________ Motor= ______________ - correct answer sensory = afferent motor = efferent Sensory neurons conduct impulses from the body to the brain and include what sensations? - correct answer temperature pressure pain Motor impulses are from the brain to the body and contain what commands - correct answer move away from stimulus move towards stimulus what 3 nerves make up the trigeminal nerve - correct answer V1 opthalmic (sensory) V2 maxillary (sensory) V3 mandibular (sensory & motor) Nerve conduction At rest - correct answer the inside of the nerve is slightly negative compared to the outside slightly permeable to sodium ions (na+) freely permeable to potassium ions (k+) how does the LA work ? - correct answer the LA enters the cell and blocks the sodium/potassium pump from the inside which stops the nerve impulse from reaching the brain. the LA has to be fat & water soluble to enter the cell. T/F Local anesthetics in solution exist in equilibrium between basic uncharged(non-ionized form) which is lipid soluble and a charged (ionized) form which is water soluble - correct answer True Why is the LA need to be non-ionized? - correct answer to penetrate the nerve membrane which is lipid soluble which once inside the cell binds to the sodium channel What is the chemical dissociation of LA - correct answer RN + H+ = RNH+ (LA BASE) (proton) (LA Cation What is pKa - correct answer the relationship between ionized and non-ionized forms of local anesthetic it is the pH at which the ionized and non-ionized forms are equal Higher pKa= - correct answer slower onset Why is pH important - correct answer Lower pH inhibits production of the base molecules Lower base molecules = insufficient anesthesia what are the LA molecule parts - correct answer lipophilic group (benzene ring) intermediate bond (ester or amide) hydrophillic group