Heart As A Pump Part 2 Flashcards
Blood volume in each ventricle at the end of diastole?
End-diastolic volume
The remaining blood volume at the end of systole?
End-systolic volume
The volume of blood ejected from one ventricle in one beat?
Stroke volume
What is the % of ejection fraction for resting dogs?
50-65%
The total volume of blood pumped by one ventricle in 1 minute?
Cardiac output
In a resting dog __-___ % of ventricular filling occurs before atrial systole: ventricles in a resting animal can pump a nearly normal stroke volume even during atrial fibrillation
80-90
During exercise, atrial fibrillation typically exhibit _______ _______
Exercise intolerance
Atrial systole is important under ______ stenosis
Mitral
___________ in end-diastolic ventricular volume causes increases in stroke volume
Increases
_________ ventricular filling during diastole places the ventricular muscle fibers in a more favorable geometry for the ejection of blood during the next systole
Greater
Stretching the ventricular muscle fibers during diastole causes a greater amount of ________ to be released from SR during subsequent systolic contraction, and this enhances force of contraction
Calcium
Increases or decreases in the _________ end-diastolic volume result in approx proportional increases or decreases in stoke volume
Ventricular
Increases in ventricular _____ bring about increases in end-diastolic ventricular volume and stroke volume
Preload
What is the ventricular pressure at the end of diastole?
Preload
In normal heart, ventricular pressure is essentially _____ to atrial pressure during ventricular filling
Equal
What is the pressure in the cranial vena cava?
Central venous pressure
The central venous pressure is __________ to the right ventricular preload
Equivalent
What is the name of the catheter that is placed into a peripheral vein and advanced into the cranial vena casa or right atrium?
Central venous catheter
What is the observation that changes in preload cause corresponding changes in end-diastolic ventricular volume and stroke volume?
Starlings law of the heart
What is the measure of the ease with which the ventricular walls stretch to accommodate incoming blood during diastole?
Compliance
A compliant ventricle is one that yields easily to _____ pressure and readily fills with blood during diastole
Preload
Compliance = change in _______ divided by change in ________
Volume
Pressure
Small changes in preload result in ____________ changes in end-diastolic ventricular volume
Substantial
An elevated preload necessitates elevated atrial and venous pressure, which can cause ________ to develop in tissues “upstream” from the stiff ventricle
Edema
The length of time available for ventricular _____ during diastole affects ventricular end-diastolic volume
Filling
What is the main determinant of diastolic filling time?
Heart rate
Heart rate _______ could limit ventricular filling and dramatically reduce stroke volume, however ___________ nervous system will compensate this influence
Increases
Sympathetic
____________ in ventricular contractility increases heart stroke volume
Augmentation
Contractility referred to the __________ ability of a ventricle
Pumping
Sympathetic nerve activity increases ventricular contractility through the action of the neurotransmitter, __________, which activated beta-adrenergic receptors on ventricular muscle cells
Norepinephrine
What 2 neurotransmitters released from the adrenal medullar and circulating in the blood can likewise activate beta-adrenergic receptors and increase contractility?
Epinephrine and norepinephrine
Cardiac glycosides: increase cytosolic Ca++ concentration during an action potential and _______ cardiac ventricular contractility
Increase
Beta-Adrenergic antagonists such as calcium channel blocking dugs
Barbiturates, opioids, and general anesthetics
_________ ventricular contractility
Decrease
Decreased cardiac contractility is the hallmark of the clinic condition called ____________ failure
Myocardial
Substantial increase in arterial blood pressure impairs ____________ ejection because the left ventricular pressure during systole must exceed aortic pressure before ejection of blood from the ventricle can occur
Ventricular
What is the pressure that a ventricle must generate in order to eject blood?
Cardiac after-load
The higher the after-load, the more ________ it is for the ventricle to eject blood
Difficult
Increasing heart rate does ____ increase cardiac output substantially unless stroke volume is maintained
Not
