Module 9 ML-6 Flashcards
What are the two functions of veins
-return blood to heart by being a big radius, low R
-act as capacitance vessel (storage)
You only need what to move large amounts of blood
small pressure
What are the four main factors that assist in venous return
-sympathetic innervation
-skeletal muscle pump
-inhalation movements
-blood volume
At rest how much of the total volume are in the veins
60%
Sympathetic innervation
sympathetically mediated venoconstriction can increased venous return to the heart and thus extra blood can be moved elswhere
Does sympathetic innervaiton change TPR
no, vasocontriction of arteries affects TPR
Example of symp innervation
veins no longer have 60% but now 50% so more blood can go other places
Skeletal muscle pump
contracting muscles increases venous pressure and the combo with one way valves promotes venous return toward the heart
What happens when we inhale
we create lower pressures in the thoracic cavity
-blood moves from veins outside the thorax to veins inside that have lower pressure
In CV system volume equates with what
pressure
more volume =
more pressure
So what happens when blood volume is low overrall
venous pressure and return are reduced
What does the lymphatic system do
clears fluids at the lymphnodes and puts them back into the CVS
What is lymphatic fluid
the 4L/day of mismatch between filtration and reabosrption in the capillaries
What does lymph also include
escaped plassma proteins and absorbed fats
