Exam 1: 28 Jan 25 CO and Valve Dysfunction Flashcards
What is cardiac output?
The volume of blood the heart pumps per minute
Normal cardiac output is around 5 liters per minute.
What is the role of nitric oxide donors like sodium nitroprusside and nitroglycerin?
They have mixed vasodilatory effects, reducing systemic filling pressure and resistance to venous return
They help improve blood flow back to the heart.
What is the function of ACE inhibitors?
They primarily act as arterial vasodilators, reducing afterload
They have various effects, including lowering blood pressure.
What happens to cardiac function with aortic stenosis?
It leads to high ventricular pressures and reduced stroke volume
Compensatory mechanisms may include increased preload and heart rate.
How is mitral regurgitation characterized?
It resembles an ‘M’ shape
Understanding the shape can help distinguish it from aortic regurgitation.
Define preload.
The volume of blood in the ventricles at the end of diastole
It affects stroke volume directly.
Define afterload.
The resistance the heart must overcome to eject blood
High afterload can reduce stroke volume.
What is contractility?
The ability of the heart muscle to contract
It is influenced by factors like calcium availability and heart rate.
What is the shape of aortic regurgitation on a pressure-volume loop?
It resembles an ‘A’ lying on its side
This shape helps in identifying the condition.
True or False: Pressure-volume loops are clinically measured.
False
They are crucial for understanding heart function but are not directly measured in clinical settings.
What do increased venous tone and sympathetic nervous system activation do during cardiac failure?
They compensate for decreased cardiac output
These mechanisms help maintain perfusion to vital organs.
Fill in the blank: _______ is the reduction of blood flow back to the heart.
Resistance to venous return
This can be influenced by medications like nitroglycerin.
What does mitral valve stenosis lead to?
Reduced stroke volume and increased preload
It affects the filling of the heart chambers.
What are the consequences of improper valve function?
Difficulty in ejecting blood and backward flow into heart chambers
It can lead to further heart damage over time.
What is hydralazine known for?
It is an arterial vasodilator with an unknown mechanism of action
It’s less commonly used in acute settings due to delayed onset.
What is the significance of understanding pressure-volume loops?
They help in understanding heart function and valve dysfunction
Important for exam preparation and clinical assessments.
What is the impact of high preload on heart function?
It may lead to heart failure over time
Excessive preload can cause stress on the heart muscle.
What happens during myocardial infarction (MI)?
Cardiac output decreases and right atrial pressure increases
Compensatory mechanisms may kick in to stabilize hemodynamics.
List the three key factors that influence normal cardiac output.
- Preload
- Afterload
- Contractility
These factors are crucial for maintaining efficient heart function.
What is the role of the sympathetic nervous system in cardiac function?
It maintains normal activity and compensates for decreased output
High sympathetic activity can stress the heart.
What should students focus on for upcoming tests regarding cardiac output and return curves?
Understanding images, bullet points, and key talking points discussed in class
Visual aids are essential for retention and comprehension.
What happens to cardiac output when the heart is damaged?
Cardiac output is too low, approximately half normal.
This occurs because the heart is no longer functioning effectively as a pump.
What is significantly elevated when the heart struggles to pump effectively?
Right atrial pressure.
This is expected when the heart is not pumping well, leading to pressure backup.
What role does the nervous system play when cardiac output is low?
It increases venous tone and tells the heart to beat stronger.
This is part of the body’s short-term compensation mechanisms.