ch 19 pt 5

Question 1

What is vagal tone?

Answer 1

Keeps resting heart rate

Question 2

What is pacemaker potential?

Answer 2

Ability to reach threshold without stimulation

Question 3

Stimulation begins at heart apex and works its way up

Answer 3

Allows for ventricles to have proper filling

Question 4

What is the default pacemaker if SA node is impaired?

Answer 4

AV node

Question 5

What is the RMP for cardiac muscle cells?

Answer 5

-90mV

Question 6

Crossbridge cycling

Answer 6

Crossbridge formation, power stroke, release of myosin head, reset of myosin head

Question 7

Cardiac cells have a long refractory period because

Answer 7

Contracts and relaxes before another stimulus

Question 8

What is an EKG?

Answer 8

Skin electrodes detect electrical signals of cardiac muscle cells

Question 9

P wave

Answer 9

Electrical changes of atrial depolarization

Question 10

QRS complex

Answer 10

Electrical changes with ventricular depolarization

Question 11

T wave

Answer 11

Electrical changes with ventricular repolarization

Question 12

Two segments between waves correspond to what?

Answer 12

Plateau phases

Question 13

P-Q segment

Answer 13

Atrial cells plateau - atria are contracting

Question 14

S-T segment

Answer 14

Ventricular plateau - ventricles are contracting

Question 15

P-R interval

Answer 15

P wave - QRS; Time to transmit action potential

Question 16

Q-T interval

Answer 16

QRS - T wave; Time of ventricular action potentials and length depends on heart rate