Heart Flashcards
Venous return
Volume of blood returning to the heart
T-wave
Following the QRS complex representing ventricular repolarization
Ventricular diastole
Dilation of the heart ventricles
Ventricular systole
Contraction of the ventricles
Sinoatrial node
Acts as the pacemaker
Initiates each heart beat
Stroke volume
Volume of blood pumped out of one ventricle of the heart In a beat
Foramen ovale
Part of the heart that closes after birth
Diastole
Relaxation of the heart chambers during which they fill with blood usually refers to ventricular relaxation
Cardiac output
Volume of blood pumped by the heart per minute
Atrial systole
Contraction of the atria.
Baroreceptor reflex
Detects changes in blood pressure and produces changes in heart rate, heart force of contraction and blood vessel diameter that return blood-pressure homeostatic levels
Cardiac reserve
Work that the heart is able to perform beyond that required during ordinary circumstances of daily life
QRS complex
Ventricular depolarization
Arrhythmia
Abnormal cardiac rhythm
Ventricular contraction begins at the…
Apex of the heart
Action potentials are slowed at the av node to allow the…
Atria to complete their contraction
Contraction of the ventricles is referred to as ventricular
Systole
Blood does not enter or leave the ventricles during the period called…
Isovolumetric contraction
In the cardiac cycle,
The two atria relax while the two ventricles contract
During the injection phase of the cardiac cycle blood enters the…
Aorta
The period of isovolumetric contraction is followed by…
The period of ejection
Pressure in the right ventricle must exceed the pressure in the _____ before the right ventricle can eject blood
Pulmonary trunk
The tricuspid valve is closed…
During ejection
Ventricular pressure exceeds atrial pressure the…
AV valves close
Afterload is…
The arterial pressure that the ventricles must overcome to eject blood.
Stimulation of the heart via the sympathetic nerves would
Increase the force of ventricular contraction
Within normal limits an increase in preload leads to…
An increase in cardiac output force of left ventricular contraction
End diastolic volume minus end systolic volume is equal to…
Stroke volume
A product of stroke volume and heart rate is known as
Cardiac output
Increased vagal stimulation would cause
The heart rate to decrease
An increase in extracellular calcium generally increases
The force of contraction
Lowered extracellular potassium levels will lower heart rate because
The resting membrane potential is hyperpolarized
Increased afterload will
Increase isovolumetric contraction
Contracting the muscles in the legs will increase or decrease end-diastolic volume
Contracting the muscles in the legs will INCREASE end diastolic volume
The degree of stretching experienced during ventricular dastardly is referred to as preload or afterload?
Preload
Withdrawal of parasympathetic stimulation (vagus nerve) decreases or increases heart rate
Increases
The relaxation phase of the cardiac cycle is referred to as diastole or systole?
Diastole
The adrenal hormones epinephrine and norepinephrine decrease or increase heart rate
Increase
During isovolumetric contraction of the atrioventricular valves are closed or open?
Closed
