FINAL EXAM - Lecture 2 Flashcards
Fluid moving out of the capillary is called
filtration
Fluid moving into the capillary is called
re-absorption
As blood moves further through vascular resistance, the pressure is
reduced
When youre taking a blood pressure, youre looking at pressure in
large arteries
When are you measuring a low pressure area as a bedside nurse
CVP
As blood is getting further from the heart, it is going through _________ cross-sectional areas.
More and more
The main drop in blood pressure between large arteries and capillaries is due to
high vascular resistance, not because of the multiple pathways it takes.
Resistance blood vessels in the systemic circulation is
arterioles
If you have a pressor that can constrict ______, that drives up blood pressure.
Arterioles
The blood vessels that contract and relax, doesnt usually happen in ______, but more in the ___ and _____.
Large arteries; small; arterioles
Flow equals
delta pressure divided by resistance
How many capillaries do we have in the body?
10+ BILLION
Capillaries are the primary place for
nutrient, waste product exchange to occur
Blood flow through the capillaries is controlled by
arterioles
What kind of muscle are arterioles?
Smooth muscle
Dilation of the arterioles will result in
increased blood flow for downstream tissues
How much surface area do we have of capillaries?
500-700 square meters
Small arteries have how many layers of smooth muscle cells?
4 layers
What controls the blood flow of capillaries? (not the physical reason of contracting)
metabolic rate
Total cross-sectional surface area of aorta is
4.5cm2
Velocity of aorta is _____. why?
High. Low surface area with a ton of cardiac output
Vena cavae surface area
18cm2
2 vena cavae’s that are 3cm each.
internal diameter of arterioles is
30um (micrometers)
Discuss the internal diameter vs wall thickness of arterioles
30um internal diameter with 20um of wall thickness. The walls are extra thick because there is lots of smooth muscle and they can contract and relax to adjust blood flow through tissue bed and adjust SVR.
Discuss internal diameter vs wall thickness of capillaries
5um internal diameter vs only 1um wall thickness, because theyre only 1 epithelial cell layer thick, and allows for products to exchange between the wall.
If norepinephrine comes in contact with capillaries, what happens?
Nothing. They don’t have smooth muscle to contract and relax.
What vessel has the fastest, and slowest velocity of blood flow?
Aorta, and veins(?, might be capillaries?)
How much total cross-sectional surface area of capillaries?
4500cm2. We dont need to know so much the exact number, but understand the trend.
This is the most surface area of any vessel in the body.
What has more total cross-sectional surface area: Aorta + small arteries + arterioles — OR — Venules, small veins, venae cavae
Venous side, much more.
Arteries have less surface area and higher velocity.
Veins have more surface area and lower velocity.
Delta P of capillary beginning and end
20
Arterial end of the capillary will be called
arteriolar
Venous end of the capillary will be called
venous end
For this class, a normal MAP will be
100mmHg
What is driving flow from one end of the tube to the other?
pressure difference.
Moving fluid from inside of the capillary, to the outside of the capillary, is called?
Filtration, on the arterial end
Moving fluid from outside of the capillary, the inside of the capillary, is called?
Re-absorption
Forces will favor _______ at the arterial end, and will favor _____ at the venous end.
Filtration; re-absorption
the four capillary starling forces are
Pcap (Pc), Pisf (Pif), PIEcap (PIEp), PIEisf (PIEif)
Pcap is also called
Hydrostatic pressure
Capillary pressure
Whats the physical fluid pressure?
Pcap/hydrostatic pressure in capillary/capillary pressure/Pc/hydraulic pressure in capillary
30 arterial end, 10 venous end
Interstitial fluid pressure names
Pif/Pisf/hydrostatic pressure in ISF
Interstitial fluid is
all the fluid outside the vasculature and outside the cells
A high Pif/Pisf around the capillary should do what to filtration and reabsorption?
Oppose filtration and promote reabsorption.
If Pif/Pisf is 10, it will oppose
filtration
In an entirely healthy patient, a normal Pif/Pisf is
negative 3mmHg
Why is Pif/Pisf negative?
Lymphatics pull excess fluid out of interstitium and causes a negative pressure.
If Pif/Pisf is -10, what is happening?
more filtration and less reabsorption