CVS Session 6- Responses Of The Whole System Flashcards
What causes an increase flow resistance to certain tissues? (Skin and gut)
A fall in arterial pressure
What causes venoconstriction?
A fall in arterial pressure
What happens if heart rate increases alone?
Cardiac output will increase to begin with, but TPR will remain the same.
What happens to stroke volume if cardiac output increases?
Venous pressure decreases, therefore stroke volume is reduced.
Why is there risk of pulmonary oedema in significant exercise?
Because the outputs of the right and left ventricles cannot be matched because the heart has been pushed to the stop of the starling curve, due to significant increased venous pressure.
Blood therefore accumulates in the lungs.
How do we prevent overfilling of the ventricles during significant exercise?
Increase the heart rate when exercise begins
What triggers the rise in heart rate at the onset of exercise?
An increase in sympathetic activity
What happens to Central venous pressure upon standing?
It falls as blood pools in leg veins
What is auto-transfusion?
The movement of fluid from extracellular space into the circulation in order to replace lost blood volume.
What organ controls blood volume?
The kidneys
What is the effect. Of prolonged increased blood volume?
Increase in venous pressure
Cardiac output increases
Arterial pressure increases
More blood to tissues, but auto regulation causes increased arteriolar tone and TPR, therefore arterial pressure increases permanently
