lecture 24 : Electrical Activity of the Heart

Question 1

What Information do the ECGs provide?

Answer 1

Information about the cardiac performance like the heart rates, rhythms and funciton

Question 2

What is the Sinoatrial node?

Answer 2

Normal Pacemaker for the heart. Has the fastest rate at around 70-80 bpm

Question 3

What are Autorhytmic cells and what are they responsible for?

Answer 3

They are cells like Sinoatrial(SA) node, the Atrioventricular (AV) node, the Bundle of His, and Purkinje fibres
They are responsible for initiating and conducting cardiac action potentials

Question 4

What are cells with highest discharge rate called? and what are they called if they have the lowest rates?

Answer 4

Highest rates: Pacemaker cells
Lowest rates: latent pacemakers

Question 5

review the spread of cardiac excitation slide on slide number 9

Question 6

What is the meaning of Excitation-Contraction coupling?

Answer 6

Its when, in a cardiac muscle an electrical signal is converted into a contractile signal

Question 7

Where is Ca2+ derived from?

Answer 7

ECF and the sarcoplasmic reticulum

Question 8

What is used to record the ECG?

Answer 8

Twelve leads or electrodes

Question 9

WHat do the P wave, QRS complex, T wave, PR segment, ST segment and TP interval represent?

Answer 9

P wave: atrial depolarization
QRS complex: ventricular depolarization
T wave: Ventricular repolarization
PR segment: Shows AV nodal delay
ST segment: occurs when the ventricles are completely depolarized
TP interval: Occurs when the heart is at rest

Question 10

What are examples of heart rate abnormalities?

Answer 10

-Tachyarrhythmias
-bradycardias