The Beating Heart Flashcards
Can heart muscle cells contract without a signal from the nervous system?
Yes
Where does the electrical signal that controls heart contractions originate?
The electrical signal originates within the heart itself.
What controls the rate and strength of heart contractions?
The nervous system.
What does the sinoatrial node do?
Controls the contraction rate of the heart.
Where is the sinoatrtial node?
In the wall of the right atrium.
Impulses from the sinoatrial node stimulate a second node. What is it called?
Atrioventricular node.
Where is the atrioventricular node located?
Bottom right atrium
What does the atrioventicular node do?
Delays impulses, allowing
ventricles to full with
blood
How do impulses traveling through the heart muscle reach the skin’s surface?
through bodily fluid
What device is used to record the electrical activity of the heart?
electrocardiogram (EKG or ECG)
Why is an electrocardiogram (EKG/ECG) useful?
Detect abnormalities
What does the P wave on an EKG represent?
The P wave represents impulses passing through the atria just before atrial contraction.
What does the QRS wave on an EKG represent?
represents impulses passing through the ventricles just before ventricular contraction.
What does the T wave on an EKG represent?
The T wave represents the return of the ventricles to their resting state.
Why can’t the recovery of the atria be measured on an EKG?
It can’t be measured because it occurs at the same time as the ventricles contract.
