Worksheets245 A&P Quiz 1B
Total questions: 40
Worksheet time: 21mins
What is the mean pulmonary capillary pressure?
15 mmHg
What is the mean arterial pressure that drives the systemic circulation?
95 mm Hg
Which part of the heart divides muscle fibers into an inflow tract and an outflow tract?
Ventricle
What is the name of the dense fibrous tissue that provides an anchorage for attachments of atrial and ventricular musculature and valvular tissue in the heart?
Annuli fibrosi cordis
What ensures one-way blood flow through the heart?
4 heart valves
Which valves open during ventricular relaxation, allowing blood to flow from the atria to the relaxed ventricles?
Contraction of the left ventricle is slightly earlier than the contraction of the right ventricle.
True
False
When do semilunar valves open?
When intraventricular pressure exceeds aortic and pulmonary pressure
What is the primary function of pulmonic and aortic semilunar valves?
To prevent backflow into the right and left ventricles
What happens after ventricular contraction and ejection?
Intraventricular pressure falls and the pulmonic and aortic semilunar valves close,
Which phase of the cardiac cycle is characterized by the first detectable rise in left ventricular pressure and the closure of the atrioventricular valves?
*See Alipoon's phases vs. book phases
Phase 2: Isovolumic contraction
What does the PR interval measure in the cardiac cycle?
The time from onset of atrial activation to onset of ventricular activation
x
In a normal cardiac cycle, what is the typical range for the PR interval?
What is the ST interval in the cardiac cycle primarily associated with?
The electrically neutral period between ventricular depolarization and repolarization
What is the duration of the QT interval, which represents ventricular depolarization and repolarization?
0.4 to 0.44 seconds
Which nerve innervates various parts of the heart, including the atria, ventricles, SA node, and AV nodes, and can result in decreased heart rate when strongly stimulated?
Which part of the nervous system is responsible for enhancing myocardial performance by increasing the influx of Ca++ during an action potential plateau and increasing both contractile strength and heart rate?
What is the role of sympathetic nerve fibers in enhancing myocardial performance?
They increase contractile strength by increasing Ca++ influx during an action potential plateau.
The effects of sympathetic stimulation depend on:
α or β adrenergic receptors
Norepinephrine or epinephrine neurotransmitter
β adrenergic receptors are more prevalent in the cardiovascular structures than α adrenergic receptors.
True
False
Which adrenergic receptor is mostly found in the conduction system, atrial and ventricular myocardium, and Purkinje fibers?
What is the primary effect of norepinephrine binding to β1 receptors in the heart?
In which part of the heart are β2 receptors more plentiful?
Coronary arterioles
What is the primary effect of epinephrine binding to β2 receptors in coronary arterioles?
Dilation of coronary arteries
Which adrenergic receptor is primarily responsible for causing vasoconstriction in the coronary arteries when norepinephrine binds to it?
What is the main effect of norepinephrine binding to α2 receptors located in sympathetic ganglia and nerve terminals?
Which four factors affect cardiac performance directly?
Preload
Afterload
Heart rate
Myocardial contractility
What is preload in the context of cardiac physiology?
The pressure generated in the left ventricle at the end of diastole
What determines left ventricular preload?
End diastolic volume
What is afterload related to in cardiac physiology?
Resistance or impedance to ejection of blood from the left ventricle
How does low aortic pressure affect afterload?
decreases the afterload
What is the definition of heart rate?
The number of cardiac cycles per minute.
What is the term for the force of contraction that ejects a certain amount of blood volume during systole?
Myocardial contractility
Which of the following are considered inotropic agents affecting myocardial contractility?
positive inotropic agents:
Epinephrine, norepinephrine, dopamine, and dobutamine
How is cardiac output expressed in terms of measurement?
Liters per minute
What are the two factors that determine cardiac output?
What is the formula for calculating cardiac output?
What is the normal range for cardiac output in a healthy individual?
5 liters per minute
How is ejection fraction calculated?
Stroke volume divided by end diastolic volume
x
What does the ejection fraction measure?
The amount of blood ejected by the ventricle in relation to end diastolic volume
