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29 Cards in this Set

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syncytium
a multinucleate mass of protoplasm produced by the merging of cells.
Hematocrit
The hematocrit is the fraction of the blood composed of red blood cells.
What are normal values of Hematocrit?
Hematocrit = 40 to 45 %, RBC's 4 to 6 million per ul.
End diastolic volume
During diastole, normal filling of the ventricles increases the volume of each ventricle to about 110 to 120 milliliters. This volume is called the end-diastolic volume.
End systolic volume
The remaining volume in each ventricle, about 40 to 50 milliliters, is called the end-systolic volume.
stroke volume output
As the ventricles empty during systole, the volume decreases about 70 milliliters.
Afterload
the load against which the muscle exerts its contractile force.

The afterload of the ventricle is the pressure in the artery leading from the ventricle.

Sometimes the afterload is loosely considered to be the resistance in the circulation rather than the pressure.
preload
it is important to specify the degree of tension on the muscle when it begins to contract, which is called the preload
Stroke work output
The stroke work output of the heart is the amount of energy that the heart converts to work during each heartbeat while pumping blood into the arteries.
Minute work output
Minute work output is the total amount of energy converted to work in 1 minute; this is equal to the stroke work output times the heart rate per minute.
Ejection Fraction
The fraction of the end-diastolic volume that is ejected is called the ejection fraction—usually equal to about 60 per cent.
(EDV-ESV)/EDV * 100
Filling Pressure
The greater the volume of blood in the circulation, the greater is the mean circulatory filling pressure because extra blood volume stretches the walls of the vasculature. The red curve in Figure 20–10 shows the approximate normal effect of different levels of blood volume on the mean circulatory filling pressure. Note that at a blood volume of about 4000 milliliters, the mean circulatory filling pressure is close to zero because this is the “unstressed volume” of the circulation, but at a volume of 5000 milliliters, the filling pressure is the normal value of 7 mm Hg. Similarly, at still higher volumes, the mean circulatory filling pressure increases almost linearly.
Diastasis
The last stage of diastole in the heart, occurring just before contraction and during which little additional blood enters the ventricle.
Heart rate
Number of heart beats per minute.
Cardiac Output (CO)
The amount of blood from each ventricle pumped per minute.

CO (volume/minute) = SV (volume/beat) * HR (beats/minute)
Cardiac Reserve
The maximum percentage that the cardiac output can increase above normal is called the cardiac reserve. Thus, in the healthy young adult, the cardiac reserve is 300 to 400 per cent. In athletically trained persons, it is occasionally 500 to 600 per cent. But in heart failure, there is no cardiac reserve.
Cardiac Index
cardiac output is frequently stated in terms of the cardiac index, which is the cardiac output per square meter of body surface area. The normal human being weighing 70 kilograms has a body surface area of about 1.7 square meters, which means that the normal average cardiac index for adults is about 3 L/min/m2 of body surface area.
Mean arterial pressure
The mean arterial pressure (MAP) is a term used in medicine to describe a notional average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.

MAP= ( CO * SVR ) + CVP
CO is cardiac output
SVR is systemic vascular resistance
CVP is central venous pressure
Pulse Pressure
The difference between systolic and diastolic pressure.

In the healthy young adult, the pressure at the top of each pulse, called the systolic pressure, is about 120 mm Hg. At the lowest point of each pulse, called the diastolic pressure, it is about 80 mm Hg. The difference between these two pressures, about 40 mm Hg, is called the pulse pressure.
Incisura
A so-called incisura occurs in the aortic pressure curve when the aortic valve closes. This is caused by a short period of backward flow of blood immediately before closure of the valve, followed by sudden cessation of the backflow.
Dicrotic notch
The acute drop in arterial pressure pulse curves following the systolic peak, corresponding to the incisura of the displacement pulse curve.
Diastole
a period of relaxation called diastole in the cardiac cycle.
Systole
A period of contraction in the cardiac cycle.
Hyperpolarization
Furthermore, the potassium channels remain open for another few tenths of a second, temporarily continuing movement of positive charges out of the cell, with resultant excess negativity inside the fiber; this is called hyperpolarization. The hyperpolarization state initially carries the “resting” membrane potential down to about -55 to -60 millivolts at the termination of the action potential.
Hyperpolarization
Furthermore, the potassium channels remain open for another few tenths of a second, temporarily continuing movement of positive charges out of the cell, with resultant excess negativity inside the fiber; this is called hyperpolarization. The hyperpolarization state initially carries the “resting” membrane potential down to about -55 to -60 millivolts at the termination of the action potential.
Depolarization
In biology, depolarization is a decrease in the absolute value of a cell's membrane potential. Thus, changes in membrane voltage in which the membrane potential becomes less positive or less negative are both depolarizations. The rising and falling phases of an action potential are often imprecisely called depolarization and hyperpolarization, respectively.
Repolarization
In neuroscience, repolarization refers to the change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of an action potential has just previously changed the membrane potential to a positive value. Repolarization results from the movement of positively charged potassium ions out of the cell. Typically the repolarization phase of an action potential results in hyperpolarization, attainment of a membrane potential that is more negative than the resting potential.
The EKG wave forms
P, Q, R, S, T
Atrial Pressure waves
a, c, & v waves