Elementary exercises in physiology . ape from theinfluence of the stimulus and willrecommence beating. Note if theauricles appear to be more inhibitedthan the ventricle. There is often a difference in effectbetween the two vagi. Sometimes onevagus is found not to possess anyinhibitory fibers, in which case theopposite vagus is usually found espec-ially active. It is generally foundthat the effect is not identical on thetwo sides, one usually being morepowerful than the arrest, or period of inhibition, is manifest in the curve bythe lever recording merely a straight line. If the laryn
Elementary exercises in physiology . ape from theinfluence of the stimulus and willrecommence beating. Note if theauricles appear to be more inhibitedthan the ventricle. There is often a difference in effectbetween the two vagi. Sometimes onevagus is found not to possess anyinhibitory fibers, in which case theopposite vagus is usually found espec-ially active. It is generally foundthat the effect is not identical on thetwo sides, one usually being morepowerful than the arrest, or period of inhibition, is manifest in the curve bythe lever recording merely a straight line. If the laryngeal musclescontract, and thereby affect the position of the heart, divide thelaryngeal branches of the vagus. There is an appreciable time or latent period, before the heartreacts to the and likewise when the stimulus is removedthe heart do^ not at once regain its normal movement. Note thatwhen the heart begins to beat again the beats are at first small andgradually rise to normal. In some instances, however, they are 109. Pig. 29.—^Cardiac Nerves ofthe Prog. (Poster). more vigorous and quicker. Cut both vagus nerves and comparethe tracing with those just obtained. 332. Action op Drugs on Heart. The experiments may beperformed upon a heart which has been removed and placed in awatch-glass or preferably upon the heart in its natural position. Muscarine. Pith a frog, expose the heart and with a fine pipetteapply a drop of serum or saline solution containing a trace ofmuscarine, which rapidly arrests the rhythmical action of the heart,the ventricle being relaxeid, i. e., diastole, and distended with a tracing from the heart while under the influence of muscarine. Atropine. Remove the solution of muscarine as much as possibleby absorbing it with filter paper and after a few minutes, withanother pipette, apply a few drops of a solution of atropinesulphate in saldne solution, the heait gradually again begins to beatrhythmically. Get a tracing. Pilocarpine.
Size: 1431px × 1746px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectphysiology, bookyear1
