Podcast
Questions and Answers
What is the primary role of the intrinsic conduction system of the heart?
What is the primary role of the intrinsic conduction system of the heart?
Which part of the electrocardiogram (ECG) represents ventricular depolarisation?
Which part of the electrocardiogram (ECG) represents ventricular depolarisation?
What physiological feature causes atrial cells to have a contraction rate of 60 contractions per minute?
What physiological feature causes atrial cells to have a contraction rate of 60 contractions per minute?
Which interval on an ECG indicates the time taken for atrial depolarisation and conduction through the AV node?
Which interval on an ECG indicates the time taken for atrial depolarisation and conduction through the AV node?
Signup and view all the answers
What effect do sympathetic nerves have on heart rate?
What effect do sympathetic nerves have on heart rate?
Signup and view all the answers
The T wave in an ECG is associated with which physiological process?
The T wave in an ECG is associated with which physiological process?
Signup and view all the answers
Which of the following leads is not part of the limb leads in an ECG?
Which of the following leads is not part of the limb leads in an ECG?
Signup and view all the answers
What does the ST segment of an ECG represent?
What does the ST segment of an ECG represent?
Signup and view all the answers
What is the duration of the QRS complex in seconds?
What is the duration of the QRS complex in seconds?
Signup and view all the answers
Which of the following is NOT a type of ECG lead?
Which of the following is NOT a type of ECG lead?
Signup and view all the answers
Study Notes
The Electrocardiogram
- The electrocardiogram (ECG) is a graphical representation of electrical activity in the heart over time.
- It's used to diagnose various heart conditions.
Intrinsic Conduction System of the Heart
- Cardiac muscle cells contract spontaneously and independently.
- They contract continuously and regularly.
- Different heart areas have differing rhythms:
- Atrial cells contract at 60 contractions/min.
- Ventricular cells contract at 20-40 contractions/min.
- A control system ensures efficient heart pumping.
Regulation of Heart Activity
- Two autonomic nervous systems regulate the heart:
- Parasympathetic nerves slow heart rate.
- Sympathetic nerves increase heart rate.
- The intrinsic conduction system (nodal system):
- Sets the heart's basic rhythm at approximately 75 beats/minute.
- Makes the heart depolarize in one direction only.
- Consists of specialized tissues forming the conduction pathway.
The Electrocardiogram (12-Lead ECG)
- Typically a 12-lead ECG.
- Einthoven's triangle represents the heart's position using electrodes:
- On both arms (Leads I & II).
- On the left leg (Lead III).
- Limb Leads: The electrodes on the arms and legs.
- Unipolar chest leads (V1-V6): Six electrodes placed on the chest.
- 3 unipolar augmented limb leads (aVR, aVL, aVF): Electrodes placed on the limbs, provide augmented views.
Position of ECG Leads
- ECG leads are positioned to view different parts of the heart.
- Leads used to view different parts of the heart:
- Inferior: II, III, aVF
- Lateral: I, aVL, V5, V6
- Anterior: V3, V4
- Septal: V1, V2
The ECG (Waves, Segments, Intervals)
- P wave: Atrial depolarization.
- QRS complex: Ventricular depolarization.
- ST segment and T wave: Ventricular repolarization.
- U wave: Slow repolarization of papillary muscles (inconsistent).
- PR interval: Atrial depolarisation & AV node conduction (0.12-0.20 seconds).
- QRS duration: Ventricular depolarisation & atrial repolarisation (0.10 seconds).
- QT interval: Ventricular depolarisation & repolarisation (up to 0.43 seconds).
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the fundamentals of the electrocardiogram (ECG) and the intrinsic conduction system of the heart. Understand how the heart's electrical activity is measured and the regulation of its rhythms. Test your knowledge on cardiac muscle contraction and the role of the autonomic nervous system in heart regulation.
