1 / 11

Cardiovascular System p. 347-352

Cardiovascular System p. 347-352. Heart Actions. Cardiac Cycle. One complete heartbeat Atrial contraction, ventricular relaxation Atrial relaxation, ventricular contraction Pressure within heart Rises and falls as chambers fill and empty Atrial or Ventricular Contraction

sarila
Download Presentation

Cardiovascular System p. 347-352

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cardiovascular System p. 347-352 Heart Actions

  2. Cardiac Cycle • One complete heartbeat • Atrial contraction, ventricular relaxation • Atrial relaxation, ventricular contraction • Pressure within heart • Rises and falls as chambers fill and empty • Atrial or Ventricular Contraction • (Systole) Pressure • Pressure increases sharply • Atrial or Ventricular Relaxation • Diastole Pressure • Pressure goes back down • AV Valves are opening and closing during pressure changes

  3. Heart Sounds • Vibrations in heart tissue produce opening and closing of valves • Heard as LubDup through stethoscope • Lub • Heard during ventricular contraction (AV valves are closing) • Dup • Heard during ventricular relaxation (pulmonary and aortic valves are shutting) • MurMur • Abnormal sound • Usually occurs when heart valves don’t properly close causing blood to leak through

  4. Cardiac Muscle Fibers • Act like skeletal muscles but connect to a network of sending impulses to contract all as a unit. • Functional Syncytium • Mass of merging cells that act as a unit

  5. Cardiac Conduction System • Coordinates events of cardiac cycle • Sinoatrial Node (SA Node) • Small mass of elongated specialized cardiac muscle tissue • Cells reach threshold on own and membranes contract one another • Initiate impulses that spread into the surrounding myocardium and stimulate cardiac muscle fiber to contract • Rhythmic activity • 70-80 impulses/min. (Pulse) • Pacemaker (Rhythmic contracting)

  6. Atrioventricular Node (AV Node) • Located in septum • Receives slow impulse • After received impulse AV node sends it on to AV Bundle • Purkinje Fibers • Allow transmission of impulse for contraction of the ventricles and pushes blood on out to aorta

  7. ECG/EKG…Electrocadiogram • Recording of the electrical changes in the myocardium during cardiac cycle • Deflections = waves on paper • Polarization and repolarization causes pen to move

  8. P QRS T Waves • P wave • Depolarization, contraction of atriums • QRS Complex • Waves correspond to depolarization of ventriular fibers that contract ventricles, atriums relax, ventricles contract • T wave • Ventricles relax, pattern ends • P-R Interval • Wave travels through AV node, AV bundles, bundle branches and purkinje fibers • S-T Segment • Time for complete excitation of ventricles • Q-T Interval • Time required for complete excitation and recovery of ventricles • T-P Interlude • Time from completion of ventricular repolarization to next atrial excitation

  9. Regulation of Cardiac Cycle • Read p. 356 • Arrhythmia • Abnormal heart rhythm • http://www.youtube.com/watch?v=xw4nDMgTOrw

  10. Review • Describe the pressure changes in the atria and ventricles during a cardiac cycle. • What causes heart sounds? • What is a functional syncytium? • How is a cardiac impulse imitated? • How is a cardiac impulse transmitted from the right atrium to the other heart chambers?

More Related