Apedia

A-Level Biology OCR A

Ventricles Wave Excitation Node Causing Contract Describe Happening

The P-wave on an ECG represents atrial depolarization from the SA node, causing atrial contraction. The PR segment indicates the AV node delay. The QRS complex shows ventricular depolarization from the apex, causing ventricular contraction. The T-wave represents ventricular repolarization.

The P-wave on an ECG represents atrial depolarization from the SA node, causing atrial contraction. The PR segment indicates the AV node delay. The QRS complex shows ventricular depolarization from the apex, causing ventricular contraction. The T-wave represents ventricular repolarization.

Front Describe what is happening in the heart at each stage of an ECG.
Back
ECG stages:
  • P-wave - wave of excitation spreads over both atria from SA node causing the atrial muscles to contract
  • PR segment - delay at AV node to allow filling of ventricles
  • QRS complex - wave of excitation spreading up walls of ventricles from the apex, causing ventricles to contract
  • T wave - ventricles repolarise after which - ventricular diastole

Learn with these flashcards. Click next, previous, or up to navigate to more flashcards for this subject.

Next card: Heart explain calculate rate ecg calculating count number

Previous card: Draw label ecg names sections

Up to card list: A-Level Biology OCR A