Lecture 7 - Exam #1 ECG Material

Question 1

PNS Stimulation primarily innervates what part of heart?

Answer 1

Nodal tissue

Question 2

Uses ACh at pre-ganglionic synapse

Answer 2

SNS

Question 3

Primarily innervates the ventricles

Answer 3

SNS

Question 4

Utilizes ACh throughout all ganglia

Answer 4

PNS

Question 5

What is responsible for the baseline of ‘0’ mV on an ECG?

Answer 5

lack of current flow

Question 6

normal P-R Interval

Answer 6

0.16 sec

Question 7

Normal Q-T Interval

Answer 7

0.35 sec

Question 8

Mechanism of SNS on heart (not the NT, but HOW it changes heart rate).

Answer 8

Increased Na/Ca influx produces (+) ino/chrono/dromotropic effects

Question 9

Mechanism of PNS changes to heart (not NT, but actual. Echo is. Of changing HR)

Answer 9

Believed to be an increase in K+ efflux

Question 10

Velocity of blood in aorta

Answer 10

Approximately 40cm/s

Question 11

Describe the mechanism behind almost constant forward blood flow, even during diastole.

Answer 11

Elastic nature of arterial walls causes the to “spring back” after deformation during systole. This “squeezes” blood forward during diastole.