Heart Structures Flashcards
What is the function of the Right Atria?
Receives deoxygenated venous blood returning from the body
It is a low-pressure chamber.
What does the Left Atria receive?
Oxygenated blood from the lungs
What is the role of the Interatrial septum?
Separates the two atrias and contains the foramen ovale in fetal circulation
What is the function of the Right Ventricle?
Pumps deoxygenated blood to the right and left lungs
What does the Left Ventricle do?
Pumps oxygenated blood to the body
What is the Interventricular septum?
Separates the two ventricles
What are the atrio-ventricular valves on the right and left sides?
- Right side: Tricuspid valve (three flaps)
- Left side: Bicuspid or mitral valve (two flaps)
What is the purpose of the Semilunar Valves?
Prevent backflow of blood into the ventricles
Where is the Pulmonary semilunar valve located?
Between the right ventricle and lungs
What does the Aortic valve separate?
The left ventricle from the aorta
Fill in the blank: Oxygen poor blood drains to the Rt. Atria from the body via the _______.
Superior and Inferior Vena Cava
What happens after blood passes from the Right Atria?
It goes through the tricuspid valve to the Right Ventricle
What is the only artery that carries deoxygenated blood?
The Right and Left pulmonary arteries
What do the Right and Left pulmonary veins carry?
Oxygenated blood from the lungs
What is the purpose of the mitral valve?
Allows blood to flow from the Left Atria into the Left Ventricle
What occurs during the contraction of the Left Ventricle?
Blood is forced through the aortic semilunar valve into the aorta
True or False: Both atrias contract together and both ventricles contract together.
True
What leads to a P wave on the EKG?
Atrial contraction at the end of diastole
What is the role of the SA node?
It is the pacemaker of the heart, pacing 60-100 beats/min
What does the impulse from the SA node stimulate?
Contraction of the atria
Where is the AV node located?
In the inferior portion of the interatrial septum
What is the pacing rate of the AV node?
40-60 beats/min
What does the Bundle of His do?
Conducts impulses down both sides of the interventricular septum
What leads to ventricular contraction on an EKG?
Depolarization caused by stimulation of the Purkinje fibers
What does the P wave on an ECG indicate?
Atrial depolarization (contraction)
What does the QRS complex represent in an EKG?
Ventricular depolarization (contraction)
What does the T wave indicate?
Ventricular repolarization (ventricles returning to resting state)
What is the normal PR interval time?
< 0.20 seconds
This corresponds to 1 large box on EKG paper.
What is the normal QRS interval time?
< 0.12 seconds
This corresponds to 3 small boxes on EKG paper.
What does the cardiac output equation represent?
CARDIAC OUTPUT = STROKE VOLUME X HEART RATE
This equation indicates how much blood is pumped by the heart in a given time.
What is preload?
The amount of blood volume inside the ventricle leading to ventricular stretch prior to contraction
Preload affects the strength of the heart’s contraction.
What is stroke volume?
Amount of blood ejected with each heartbeat
Stroke volume is a key component in determining cardiac output.
How is heart rate defined?
How fast the heart beats, measured in beats per minute
Heart rate is a crucial factor in overall cardiovascular function.
What does resistance refer to in the cardiovascular system?
How far x diameter of the pipes or vessels
Resistance affects blood flow and pressure in the circulatory system.