Cardio 5

Question 1

T or F
All deoxygenated blood passes through either the SVC or the IVC on its way to the right atria. Why?

Answer 1

F
the coronary circulation has its own opening directly into the right atria

Question 2

T or F
The Purkinje fibres can fire independently if the sinus node doesn’t generate an impulse. Why?

Answer 2

T
all cells in the conduction of the heart can fire their action potential to beat on their own, however, the sinus node is usually faster and “controls” the electric activity

Question 3

T or F
The Purkinje fibres form synapses with the myocardium in ventricles, allowing ventricles to fire in synchrony

Answer 3

F
The whole statement is true EXCEPT CARDIAC CELLS DON’T HAVE SYNAPSES

Question 4

Na+ ions passes through gap junctions of cells where one is active and the other is resting

Answer 4

T
It is a very small amount but Na+ does travel through the gap junction (most in the interstitial fluid)

Question 5

What is a ECG/EKG

Answer 5

a recording of the electrical activity of the heart

Question 6

What is the difference between ECG and EKG

Answer 6

ElectrocardioGRAPH: the device
electrocardioGRAM: the recording

Question 7

What is the order of “waves” on the ECG reading

Answer 7

P QRS T

Question 8

What happens during the P-wave? What is visible on the ECG reading, and why?

Answer 8

1. Sinus node fibres: invisible
2. Atrial activation: visible
3. AV node activation: invisible
   Anything that is a small activity will not appear on a reading

Question 9

What happens during the Q-wave? What is visible on the ECG reading?

Answer 9

1. His bundle activation: invisible
2. Left bundle activation: invisible
3. Septum activation: visible, Negative deflection

Question 10

What happens during the R-wave? What is visible on the ECG reading?

Answer 10

1. Purkinje fibres activation: invisible
2. Ventricle activation

Question 11

What happens during the S-wave? What is visible on the ECG reading?

Answer 11

1. late activation of the ventricle: visible

Everything is activated at the end of this wave

Question 12

How can the QRS complex be identified?

Answer 12

It’s the first negative deflection from the baseline

Question 13

What happens during the T-wave? What is visible on the ECG reading?

Answer 13

1. Ventricle repolarization: visible

Question 14

What is a segment?

Answer 14

the baseline interval between two defelctions

Question 15

What is an interval?

Answer 15

a range including deflections

Question 16

Where is the P-R segment? What does it indicate?

Answer 16

From the end of the P to the start of the Q

It is the delay between atrial and ventricular activation

(there is no baseline between R and Q and a segment is the baseline interval so even if it is called the P-R segment it stops at Q)

Question 17

Where is the P-R interval?
What does it indicate?

Answer 17

It starts at the beginning of P and ends at the beginning of Q

It is the Atrioventricular transit time

Question 18

Where is the S-T segment? What does it indicate?

Question 19

Where is the Q-T interval? What does it indicate?