Practice questions lecture 6 Flashcards
Which area of autorhythmic cells being solely intact/functioning would cause the most severe cardiac related symptoms?
Bundle of His/Purkinje fibers
Which path is longer, the interatrial or internodal pathway?
Interatrial
The refractory period of cardiac muscle is ______ compared to the duration of the contraction.
Long
What area of autorhythmic cells fires at a rate of 40-60
APs per minute?
AV node
What rate do the bundle of His/ purkinje fibers fire at?
20-40
Action potential arrives at AV node ________ after SA node firing
30ms
Where do the 4 major EKG leads go?
1) Right arm white
2) Right leg green
3) Left arm black
4) Left leg red
What does the T wave represent?
Ventricular repolarization
True or false? The SA node does not generate enough activity to reach the body surface, so it is not seen on an EKG.
True
What does the PR segment of an EKG represent?
AV nodal delay
What part of an EKG represents ventricular plateau phase?
ST segment
_______ elongation can be caused by Zofran and Z-pack
QT
Use 2 words to describe fibrillation
Rapid and irregular
What EKG abnormality is described as necrosis due to lack of O2/blood?
Infarction
An abnormality where the ventricles occasionally fail to be stimulated is called?
Block
The time between ventricular repolarization and another atrial depolarization is called?
Mid-ventricular Diastole
The SA node reaches threshold and fires (atria contract) during which stage?
Late ventricular diastole
The end-diastolic volume of the ventricles (maximum amount of blood) is what?
135mL
The AV valves close and the ventricles contract when?
Onset of ventricular systole
What stage of heart contraction are all valves closed and no blood is entering or leaving?
Isovolumetric ventricular contraction
When does isovolumetric ventricular contraction occur?
Right after the onset of ventricular systole
What is the amount of blood pumped out of the ventricle with each contraction?
Stroke volume
End-systolic volume averages ____, while stroke volume averages around ______.
65mL, 70mL
What equals stroke volume?
EDV - ESV
For ventricular filling to begin, ______________ pressure falls below _____________ pressure
ventricular; atrial
When does isovolumetric ventricular relaxation occur?
Onset of ventricular diastole
What does the QRS complex of the cardiac cycle represent?
Ventricular depolarization
What is occurring during atrial depolarization (P-wave)?
Atria are contracting and forcing blood into ventricles
What occurs during the QRS complex?
Ventricular depolarization; ventricular contraction closes AV valves
What occurs during ventricular repolarization (t wave)?
SL valves open and blood is ejected from ventricles
Systole lasts _________ms, diastole lasts ____________ms
300ms; 500ms
True or false? Systole is longer than diastole.
False
When heart rate is rapid, which phase of the cardiac cycle is shortened?
Diastole
Total cardiac output equals what times what?
SV x heart rate
Heart rate determined primarily by what?
Autonomic influence on SA node
How does stimulation of the vagus nerve impact the heart?
Decrease HR, increase AV node refractory period, increase PR (pulse rate)
How does norepinephrine from sympathetic nerves binding to B1 receptors affect the heart?
Increase HR, decrease AV refractory period, decrease PR, increase contractility (SV)
____________________ law states that when the volume of blood in the ________________ increases, the stroke volume also increases?
Frank-Starling law; ventricles
What are heart sounds caused by?
Vibrations in the ventricles and major arteries
True or false? AV valves close during S1, while semilunar valves close during S2.
True
What is the most common cause of turbulence?
Valve malfunction
What kind of sound does a stenotic valve produce?
Whistling
Frank-starling law: Increased venous return increases ______________ volume
stroke
True or false: Different activities result in differences in venous return
True
Cardiac muscle fiber length is determined by what?
EDV
What causes MI in 50% of deaths?
Coronary artery disease
Greater EDV (greater filling) = ______________ force of contraction
greater
Is S1 or S2 low-pitched, soft, and long?
S1
What sound does an insufficient/ incompetent valve produce?
Gurgling, swishing
Do insufficient valves cause regurgitation, or stenotic valves?
Insufficient
What kind of sound does a stenotic valve produce?
Whistling
_______ murmurs occur between first and second heart sounds while _______ murmurs occur between second and first heart sounds.
Systolic, Diastolic
A whistling systolic murmur could be what?
Aortic/pulmonary stenosis
True or false? Diastolic HF is when the heart can’t fully fill, while systolic HF is when the heart can’t fully pump.
True
Name the 3 mechanisms caused by the condition that causes MI in 50% of deaths
Vascular spasm
Atherosclerosis
Thromboembolism
Contractility decreases in what type of heart failure?
Systolic
Decompensation and congestive heart failure where talked about in the context of ____________ heart failure
systolic
