The Conducting System

Question 1

What is the function of SA Node?

Answer 1

Can discharge action

potential spontaneously

Question 2

The SA Node is supplied by the

Answer 2

sympathetic and parasympathetic

Question 3

The action potential of SA Node is characterized by the

Answer 3

The pre potential (unstable

resting membrane potential))

Question 4

The AV node has the _________ conduction of velocity

Answer 4

slowest

Question 5

Purkinje fibers has the ________ conduction of velocity

Answer 5

highest

Question 6

Define ECG

Answer 6

The sum of all action potentials that occur in the heart

Question 7

What are the requirements for recording the ECG?

Answer 7

•Ten electrodes•
Nine active (to chest & limbs) and One inactive (to right leg)

Question 8

How is unipolar recording done?

Answer 8

• By one active electrode + an inactive electrode

* Gives nine unipolar leads

Question 9

How is bipolar recording done?

Answer 9

•Two active electrodes + inactive
electrode
•Gives three bipolar leads

Question 10

The normal ECG consists

of 12 leads; What are they?

Answer 10

3 bipolar limb
leads, 3 augmented limb
leads and 6 chest leads.

Question 11

The ECG cannot detect______

Answer 11

the mechanical events in the heart i.e contraction or relaxation

Question 12

What are the Normal ECG waves?

Answer 12

• P wave
• QRS complex
• T wave

Question 13

Where does the wave of depolarization move from?

Answer 13

from the base of the

heart to the apex and from inside to outside.