Exam 3 CVS 5-8 Flashcards
The function of the ventricles is defined by 3 factors:
- stroke volume
- ejection fraction
- cardiac output
The volume of blood ejected on one ventricular contraction
Stroke volume
stroke volume is the difference between:
the volume of blood in the ventricles before ejection and the volume remaining after ejection
the fraction of the end diastolic volume that is ejected on one stroke volume
ejection fraction
the inc. or dec. in ejection fraction reflects and inc. or dec. in ______
contractility
the total volume of blood ejected per unit time
CO
4 factors that affect CO:
- body metabolism
- exercise
- age
- body size
Cardiac output can be increased if ____ or ____ are increased
SV; HR
three things that affect stroke volume:
- Preload
- contractility
- afterload
If end-diastolic volume increases then SV will_____
increase
If end systolic volume is decreased then SV will____
increase
The workload imposed on the heart before contraction begins
Preload
what are the 2 factors that determine preload?
- diastolic filling
2. venus return
what is another term for preload?
end diastolic volume
What does the frank-starlin mechanism state?
the volume of the blood ejected by the ventricles depends on the volume present in the ventricle at the end of diastole
The pumping ability of the ventricle
contractility/ inotropism
an increase in contractility leads to a/an ______ in stroke volume
increase
an increase in contractility leads to a/an ______ in systolic volume
Decrease
what are 2 extrinsic factors that have a positive ionotropic effect? (inc. contractility)
- sympathetic stimulation
2. cathecolamines
how doe epi and norepi stimulate an inc. in contratility?
stimulation of Beta 1 receptors to inc. Ca flow
the resistance that the ventricles must overcome to empty its content?
Afterload
what is the afterload for the L ventricle?
Aortic pressure
An inc. in afterload will cause a/an ______ in ionotropy (contractility)
How?
increase, catecolamines
sympathetic stimulation increases or decreased HR?
increases
When HR increases, contractility _______
increases
Inc. in preload causes stroke volume to _____
Inc.
Inc in contractility causes SV to ______
Inc
Dec. in afterload causes SV to _____
Inc
what are the 3 major divisions of the circulatory system?
- distribution system
- perfusion/exchange system
- collecting system
What makes up the distribution system?
Ventricles, arteries, arterioles
What makes up the perfusion/exchange system?
capillaries
What makes up the collecting system?
Venules, veins, atria
transports blood under high pressure to tissues
Arteries
the last, smallest branches of the arterial system?
arterioles
Site of the highest resistance to blood flow
Arterioles