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Terms in this set (29)
At rest, systole is about ____ of cardiac cycle and diastole is ___ of the cardiac cycle
heart is contracting but the volume is not changing
Depolarization proceeds with_____
High blood pressure increases:
Ejection fracture equation
The Auxiliary Pumps
-Pressure drops as blood gets further away from the heart
-During muscle contraction, the compress the veins and blood is pumped to the heart
The Respiratory Pump
Takes place in thoracic cavity
During inhalation, contraction of diaphragm, this decreases pressure in intrapleural space and allows for blood vessels in the thoracic cavity to open up more and dump blood into right side of the heart
The Abdominal Pump
Increase in abdominal pressure during inhalation, helps to push blood back up to the heart
Frank Starling Mehanism
Increased filling of the heart results in an increase stroke volume of the heart (more blood in, more blood out)
As EDV increases, SV increases
Stroke volume tends to level-off around __% VO2
Epinephrine and norepinephrine will...
increase HR and contractility
Ventricle walls will stretch with increased intensity
Regulates bloodflow into capillaries and helps with distribution/redistribution of bloodflow
What metabolites from exercise will vasodilator you're muscles?
CO2, H+, and heat
Fick Equation (whole body VO2)
VO2=Q x avO2 diff
What is AVO2 difference?
the difference in the circulatory system in oxygen concentration between arteries and veins (mixed venous blood)
Mixed venous blood
a mixture of venous blood from both the upper and lower extremities; complete mixing occurs in the right ventricle
True or false: avO2 and avCO2 increases greatly with exercise
Krebs cycle and ETC are causing the increase in avO2 difference due to:
Utilization of O2
True or false: At rest, only half of the cardiac cycle time is spent in diastole.
False. More like 2/3
True or false: During early exercise, the increase in heart rate is predominately caused by sympathetic stimulation.
False. Decrease in vagal tone
The heart responds to exercise by increasing all of the following:
Ejection fraction, stroke volume, and heart rate
Which of the following enhances venous return?
Skeletal muscle pump, venoconstriction, and respiratory pump
Without neural or hormonal influence, the sinoatrial node depolarizes at a rate of
Around 90-100 bpm
An increase in the preload of the heart will result in
an increase in stroke volume. This is referred to as the Frank Starling Mehanism
SV = EDV - ESV
When does the aortic valve open?
when ventricular pressure exceeds aortic pressure
The two major determinants of cardiac performance are
HR and stroke volume
thick layer of cardiac muscle that carries out the functions that are most often associated with the heart—contraction (or systole) and relaxation (or diastole).
In nonpacemaker cardiac myocytes, the AP can be divided into _____ phases that correspond to the opening of a series of protein channels in the cell membrane
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