Cardiovascular Two

Home > Flashcards > Print Preview

The flashcards below were created by user bagpuss35 on FreezingBlue Flashcards. What would you like to do?

  1. Describe the external nerve supply to the heart?
    •Sympathetic nerves fromĀ 

    • - upper thoracic spinal cord, through sympathetic chain to cardiac nerves
    • - directly to ventricular myocardium
    • - can raise heart rate to 230 bpm

    •Parasympathetic nerves

    • - right vagus nerve to SA node
    • - left vagus nerve to AV node
    • - vagal tone – normally slows heart rate to 70 - 80 bpm
    • - No vagal innervation to ventricular myocardium
  2. Describe the cardiac conduction system?
    •myogenic - heartbeat originates within heart

    •autorhythmic – regular, spontaneous depolarization

    •Sinoatrial (SA) node: pacemaker, modified cells, initiates heartbeat, sets heart rate, located in right atrium

    •fibrous skeleton insulates atria from ventricles

    •AV node: electrical gateway to ventricles in right atrium

    •AV bundle: pathway for signals from AV node into ventricles

    •Right and left bundle branches: divisions of AV bundle that enter interventricular septum

    •Purkinje fibers: upward from apex spread throughout ventricular myocardium to excite cardiomyocytes
  3. Relate the structure of cardiac muscle to its function?
    •Short, branched cells, one central nucleus

    • •Less Sarcoplasmic reticulum, large T-tubules
    • - admit more Ca2+ from ECF

    • •Intercalated discs join myocytes end to end
    • - interdigitating folds - ­ increase surface area
    • - Desmosomes - hold cells together, structural support
    • - electrical junctions - gap junctions allow ions to flow between cardiomyocytes

    •Aerobic respiration, rich in myoglobin and glycogen, large mitochondria

    •Organic fuels: fatty acids, glucose, ketones and lactic acid

    •Fatigue resistant
  4. . Explain how the SA node fires spontaneously and rhythmically?

Card Set Information

Cardiovascular Two
2012-07-10 13:01:08
Conduction system cardiac muscle electrical contractile activity

Conduction system, cardiac muscle, electrical and contractile activity
Show Answers:

What would you like to do?

Home > Flashcards > Print Preview