Movement Of Blood And Fluid Flashcards
The circulatory system is made up of two circuits. What are these?
Pulmonary
Systemic (rest of body)
What is bulk flow?
The movement of fluid due to differences in hydrostatic pressure
What is hydrostatic pressure?
The force exerted on a container by a fluid
How does the body alter hydrostatic pressure?
Vasoconstriction/dilation
What is perfusion pressure?
The pressure needed for blood to move through a blood vessel
Transmural (across an organ) hydrostatic pressure causes bulk flow across capillary walls in exchange for what?
Interstitial fluid (fluid surrounding tissues)
What is oncotic pressure?
Pressure exerted by proteins that pulls water into the blood
What protein is responsible for exerting oncotic pressure?
Albumin
What is Starling’s Law of capillaries?
Hydrostatic and oncotic pressure differences across the vessel wall balance to determine the movement of fluid
If Starling’s Law of capillaries is positive, what does that mean?
Water is filtered out of capillary
If Starling’s Law of capillaries is negative, what happens?
Water is drawn into capillaries
What removes excess interstitial fluid,and where does it go to?
Removed by lympathic system
Returned to blood stream
If the lymphatic system fails to remove excess interstitial fluid, what happens?
Oedema (XS fluid in body cavity/tissue)
Blood goes through one capillary bed and back to the heart, except for…?
In the gut, goes through the hepatic portal vein to the liver
What is cardiac output?
Stroke volume X Heart rate
What is end diastolic/systolic ventricular volume? EDVV/ESVV
The volume remaining in the ventricles at the end of systole/diastole
What is the equation between EDVV, ESVV and stroke volume?
Stroke volume = EDVV- ESVV
What is the ejection fraction?
Stroke volume/ EDVV
What is contractility?
The natural ability of a heart muscle to contract
What is preload?
The filling pressure of the ventricle
What is preload equal to?
Atrial pressure, venous pressure, EDV pressure
How is preload increased?
Increasing blood volume
Reducing blood flow to non-essential tissues
How do you increase end diastolic ventricular volume?
Increase preload
Increase diastolic filling
Increase ventricular compliance
What is compliance?
Ability to stretch
What is starling’s law of the heart?
As EDV pressure increase, so does EDVV until a certain point
Heart cannot stretch (compliance) anymore
What is the equation for compliance?
Change in volume / change in pressure
What is heterometric autoregulation?
Increasing preload causes increased EDVV and increased stroke volume
Under stress, what happens to the duration of systole? Why?
It is reduced so that there is more time to maintain diastole
