Control Of CO Flashcards
Dowmstream to the point of resistence the pressure would_________& upstream (before poimt of resistence) pressure would________
Decrease
INcrease
What is value of CO in women and male
Women=4.9L/min
Men=5.6L/min
What is the primary controller of CO?
The venous return
What is EDV? ESV?
Edv» amoun tof volume u get when ventricles r filling 110-120ml
ESV» remaining volume in ventricles after they have ejected (10-20ml)
What is preload? Afterload
Preload» pressure during filling of ventricles
Afterload»the arterial pressure against which the ventricle must contract
When volume is increased, what factors increases heart rate by 10-20%
When extra smiun tof blood comes in heart, cardiac muscle is stretched MORE, which cause heart to contract more to force that ectra blood out, also right atrial stretch will increase as well
Stretching of the heart causes the heart rate to go ______
Up
How does stretching heart effect the sinus node?
When the right atrium stretches, the sinus node at the wall of the atrium stretches as well, and has a direct effect in incfeasing the rythmicity of the node to increase heart rate 10-15%
What can lead to decreased CO?-decreased venous return
- decreased blood volume
- acute venous dilation, blood volume can no longer create adequate pressure in the peripheral bv, blood “pools” in the vessels as a result amd cannnot return back to heart
- obstruction of large veins coming into heart
- decreased skeletal muscle mass
- decreased metabolic rate of the tissues
Why does decreased metabolic rate of tissues decrease CO?
During prolonged rest for ex, the oxygen consumption and nutrition needs for that tissue is decreased,which causes blood flow to that tissue to lower, therefore decreasing CO
Why is venous resistence so important in determining the resistance to venous return
When the resistance in the veins increase, blood begins to be dammed up in the veins themeselves. However, the venous pressure rises very little bc the veins r highly distensible, therefore that tiny rise in venous pressure ismt gunna be very effective in overcoming the resistence, and blood flow to right atrium DECREASES (decreased venous return
What is physiological range for CVP?
2-6mmHG
What is CVP central venous pressure
the blood pressure in the venae cavae, near the right atrium of the heart
OR
pressure of right atrium
If the heart is pumping strongly, right atrial pressure decreases/increases?
Decreases
If you gave an individual an injection of adrenaline (at a dose
higher than the normal circulating levels in exercise) what
would happen?
It will work on the A1 recepters in bv causimg vasoconstriction
