heart review and respiratory 2 Flashcards
Where is the location of the cardiac centers that regulate heart rate?
medulla oblongata
We have said that the heart has automaticity and rhythmicity, can external influences affect pacemaker activity? How?
ECG or electrical differences
Why is an ECG good for medical fields?
it can measure the electrical activity in the heart and we can see if the heart is working abnormally
Does the ECG measure one action potential in the heart?
ECG measures the p wave, r wave, and t wave.
What electrical event does the P wave represent?
depolarization of the atria
An abnormal QRS complex would indicate an abnormality in what area of the heart?
cardiac conduction
What events are occurring during the PR interval? An increase in the PR interval might indicate an abnormality in what region of the heart?
atrial excitation until beginning of ventricular excitation. cardiac dysfunction
What are the 3 phases of the cardiac cycle?
1- Ventricular filling
2-ventricular systole
3-isovolumetric relaxation (early diastole)
If the atria could not contract what would happen to ventricular filling?
blood would not get pumped into the ventricles
diastole
relaxed
systole
contract
Explain what events are occurring during isovolumetric contraction and why they are necessary.
causes ventricular pressure to be greater than atrial pressure which produces the first heart sound
What causes ejection of blood from the heart?
The heart contracting which is a result of pressure changes
What are EDV and ESV?
EDV- end diastole volume and end systolic volume
What are the determinants of blood pressure?
the rate of blood flowing out of the heart per minute known as Q(cardiac output) which is determined by HR and SV