A&P final Flashcards
Define Filtration
Movement of fluid out of a capillary
Define Reabsorption
movement of fluid into a capillary
As blood moves across or through an area of vascular resistance the pressure ______
decreases
Where do you measure BP?
proximal to resistance
In the large arteries
what is the exception to measuring bp proximal to resistance?
CVP
In the kidney you have to take in account what kind of pressure?
pre-resistance and post resistance pressures
We only have 1 aorta but we have a bunch of large arteries and those split into even more smaller arteries. As blood moves down larger and larger cross sectional areas, what does it do to blood pressure and why?
brings bp down
Mostly d/t the increase in resistance but some of it is d/t there being many pathways for the blood to choose to go down
the vast majority of the drop in bp that happens between large arteries and capillaries is d/t
the high vascular resistance in the small arteries and arterioles
Most of our vascular resistance is in our
arterioles.
Which vessels do most of our relaxing and constricting?
arterioles
Ohm’s law can be used to describe what properties?
-action potentials with membrane resistance
-blood flow
Which formula is very useful in the body?
Ohm’s law
V=IR
Where is the primary place where nutrient and waste exchange happens?
capillaries
blood flow through the capillaries is controlled by the
arterioles
which vessel has a lot of smooth muscle associated with it?
arterioles
what allows us to regulate our blood flow in our arterioles to downstream tissues ?
smooth muscle cells
what is the surface area of capillaries in the body?
500-700 square meters
small arteries are an important place where we regulate our _____
bp
how many layers of smooth muscle is lined on the small arteries and arterioles?
4?
What kinds of nutrients are delivered to the arterioles?
glucose
fats
cholesterol
Gasses: offloading oxygen & picking up CO2
name of the vascular tree?
Mohrman
How many aortas do we have?
What is the cardiac output?
what is the Cross sectional area of the aorta?
what is the total cross sectional area?
what does that tell us about velocity?
We have 1 aorta so 5L/min CO has to get through that. It only has a 2.5cm2 cross sectional area. With such a low cross sectional area through just 1 aorta that gives us a total cross sectional area of 4.5cm2.
So Velocity is high, especially when the heart is in systole
What are the large veins that return blood to the heart?
venae cavae
What is the internal diameter of the venae cavae?
Is this smaller or larger than the aorta?
3cm
larger
How many venae cavae do we have?
what is the Cross sectional area of the venae cavae?
What is the total cross sectional area?
what does that tell us about velocity?
We have 2 venae cavae both with a cross sectional area of 3cm.
This makes the total cross sectional area 18cm2
This would make velocity lower in the venae cavae than in the aorta.
velocity is ______ in the vena cavae than in the aorta?
Why?
lower
Because there is a much higher total cross sectional area when blood is returning to the right atrium. (18cm2 vs 4.5cm2)
what is the internal diameter of an arteriole?
30 micrometers
Why are arteriole walls thick?
Because they have a lot of smooth muscle cells around them which helps us regulate our SVR and regulate blood flow through any tissue bed.
There is a very high wall thickness to internal diameter ratio in
arterioles
Capillaries have very ___ walls
thin
How many cell layers thick is the capillary wall?
What kind of cell is this?
endothelial cells
1 layer thick
Can capillaries contract or relax?
No, they don’t have any smooth muscle
Why doesn’t NE effect capillaries?
There’s no smooth muscle for it to act on. It only effects the arterioles.
Why is it good that capillaries have thin walls?
Increases nutrient absorption and waste removal d/t having a thin barrier
which vessel has the fastest velocity?
aorta
Order of velocity through vessels from fastest to slowest?
aorta
veins
capillaries
cross sectional areas from smallest to largest.
Don’t have to know the numbers.
aorta 2.5cm2
venae cavae 8cm2
small arteries 20cm2
arterioles 40cm2
small veins 80cm2
venules 250cm2
capillaries 2500cm2
What makes up the tendency for fluid to move through the capillary?
Delta P
30mmHg-10mmHg= 20mmHg
What is the average aortic bp?
100mmHg
Why does pressure drop from 100mmHg to 30mmHg from the left atrium to the capillaries?
The bp has gone down in the upstream high resistance blood vessels
Name for beginning end of the capillary? what is the pressure here?
arteriolar end of capillary
arterial end of capillary
30mmHg
Name for end of the capillary? What is the pressure here?
Venous end
10mmHg
Normal Map is
100mmHg
At the venous end of the capillary there are forces that favor ______
reabsorption
At the arteriolar end of the capillary there are forces that favor ______
filtration
In filtration, fluid and nutrients are ____ the capillary
leaving
In reabsorption fluid and waste products are _______ the capillary
going into
Besides delta P, there are certain variables that determine filtration and reabsorption. What are these called?
the 4 capillary starling forces
what are the starling forces?
- PCAP:BP/hydrostatic of capillary
- PISF:BP/hydrostatic pressure in ISF
- πCAPCapillary Colloid Osmotic Pressure; Oncotic pressure
- πISF: ISF colloid osmotic pressure
Filtration coefficient:
Kf:capillary permeability, #’s and surface area
What is another name for BP in the capillary?
hydrostatic pressure
hydraulic pressure
physical fluid pressure
that exists in the fluid in the capillary
What is the hydrostatic pressure in the capillary?
Why are these pressures important?
30mmHg at arterial end
10mmHg at venous end
They’re important in determining how much fluid goes DOWN the capillary as well as how much fluid goes THROUGH the capillary wall
PCAP stands for:
hydrostatic pressure
blood pressure
physical fluid pressure in the capillary
What is the interstitial fluid pressure?
The pressure outside of the capillaries
PISF stands for:
hydrostatic pressure
blood pressure
physical fluid pressure in the interstitial fluid
Having a high or POSITIVE pressure in the ISF around the capillary would effect filtration and reabsorption how?
oppose filtration at the arterial end
or, if it is high enough, it would promote reabsorption at the venous end
In the interstitium, on average when we’re healthy, the PISF is usually
-3mmHg
The lymphatic system acts like a vacuum
Why is PISF normally negative?
Lymphatics operate to pull excess fluid from the interstitial. This ends up being really effective
Lymphatic acts as a _____ on the interstitial fluid in a normal healthy person
vacuum underneath the skin
what creates osmotic pressure inside the capillary and in the ISF?
proteins
If the cell wall is not permeable to proteins (dissolved colloids) but is permeable to fluid and other smaller stuff, there is going to be ________.
What effect is this going to have on fluids in the capillary?
osmotic pressure
This holds fluid inside of the capillary
What do we call the force that dissolved colloids create when dissolved in the plasma?
plasma colloid osmotic pressure
plasma oncotic pressure
What is the normal plasma oncotic pressure in the afferent arteriole?
28mmHg
What are the specific blood colloids that make up our plasma osmotic pressure and hold fluids in the cardiovascular system?
albumin
fibrinogen
immunoglobulins
If we hemorrhage or are in liver failure and we loose fluid in the cardiovascular system then we have a really low_____
oncotic pressure d/t us losing the colloids that normally hold the fluid in the CV system
If you have a normal oncotic pressure and then the cell wall becomes more porous, what will happen? (swiss cheese)
You would lose proteins
It is not necessary for us to lose proteins for this situation to be bad b/c if the holes are big enough in the wall for proteins to leak out, then you have lost all of your osmotic pressure.
Osmotic pressure is dependent on a
semipermeable membrane where fluid can move but some dissolved substances can’t. Swiss cheese walls gets rid of your semipermeable membrane and therefore gets rid of your osmotic pressure
When you have a pt. with sepsis and you give proteins like albumin, the proteins will probably leak out of the vessel. Why is this the secondary problem?
The primary problem is that the vessel has lost all of its oncotic pressure d/t the semipermeable membrane being destroyed by holes in the wall.
what are the proteins on the other side of the capillary wall? (the ISF)
matrix proteins and substances in the interstitial space:
proteoglycan filaments
hyaluronic acid
Collagen
what are the very big proteins in the ISF?
proteoglycan filaments
hyaluronic acid
collagens
There are way more proteins _____ the CV system than ______ the CV system. They both create osmotic pressure but the ISF is usually ______ by the capillary pressure.
inside (28mmHg)
outside (8mmHg)
outweighed
What is the number for osmotic pressure of ISF around capillaries
8mmHg
What could cause more “stuff” to be released into the ISF?
Damage- crush injury, bacteria or viral infection, trauma i.e. bang our head
If we destroy our cells in a disorganized (unplanned) way what would you expect to happen to the ISF?
Everything inside of cell leaks out into the ISF if cells burst open. This increases the osmotic pressure in the ISF which pulls fluid out of the capillaries and causes swelling.
When capillaries turn into swiss cheese d/t things like sepsis, it makes a source for ____ to leak out into the ISF.
proteins
sepsis causes extra proteins to leak into the_____
When the cardiovascular cells heal it blocks the “door” for proteins to go back into the capillary which causes
ISF
continued swelling that is hard to fix, even though the patient has gotten rid of the infection.
What helps decrease swelling in the ISF over time?
lympatics
What increases the rate that the lymphatics reabsorb fluids and some proteins in the ISF?
moving around.
Swelling is worse in bed bound pts because the lymphatics are having a harder time with no movement.
What is the only way for fluids to get back into the plasma(CV system) from the ICF?
lymphatics
Lymphatics can increase its’ absorption rate of _______ ____ to _____ times its normal amount in someone who is healthy
fluid
20-40X
lymphatics are more specific for ___ than ____ scavenging.
It takes a lot longer for the lymphatic system to scavenge ____ than _____
fluid
proteins( and all that other garbage)
proteins
fluids
A surgeon has to know the topography of which system that is difficult to study d/t it not really showing up on MRI’s?
Lymphatic system
If surgeon makes a big cut and cuts the lymphatic system what could happen?
They’d have a swollen limb for the rest of their life
what is Kf?
a function of how permeable the capillaries are to fluids
If the capillary is really porous to water we’d expect lots of water to be able to move. It also takes into account surface area which can be changed if the capillary expands for some reason
If a capillary is larger than normal then we’d have _____ surface area which means we’d have ______ movement of fluids
more
more
What are the 3 main components that are the primary drivers for the plasma protein osmotic pressure/ oncotic pressure in the capillaries?
What is the total pressure?
Primary: albumin
Secondary: Globulins; antibodies and things generated by the immune system
Tertiary: Fibrinogen; coagulation factor
Total of these is 28
What are the areas of collection in the lymphatic system?
lymph nodes
As we move and walk around we have some “light muscles” activated which drives ______ through both the venous blood system and lymphatic system
flow
What is the one way valve system that relies on us compressing and relaxing our skeletal muscles against the lymphatic system which also has ______
venous system
one way valves
The lymphatic system is always going to be returning our lymphatic fluid flow back into the cardiovascular system at the top of the _____.
This is where we have lymphatic ______ that connect with very large ______
chest/ thorax
ducts
veins
Compression of the one way valves in lymphatic system by muscles contracting and relaxing makes the valve ____
open.
It is “giant passive one way pumping system”
What is this graph showing us?
Lymphatic flow capacity.
As we increase activity, our lymphatic flow increases. In this graph it increases 20 fold but could
possibly go higher than 20 fold
What can help to increase movement of lymphatic fluid and venous blood in the bedbound patient?
SCD
The movement of lymphatic fluid could possibly be more important than the movement of ____ in regards to SCDs
venous fluid
What number represents the net pressure for filtration at the arterial end of the capillary?
13mmHg
What number represents the net filtration pressure at venous end of the capillary?
-7mmHg
How to get the Net Filtration Pressure at the arterial end of the capillary?
30mmHg hydrostatic pressure in the capillary that promotes filtration
+3mmHg ISF hydrostatic pressure that promotes filtration
+8mmHg osmotic pressure of the proteins outside of the capillary that promotes filtration
= 41mmHg total promoting filtration.
-28 plasma oncotic pressure in the capillary that opposes filtration
41mmHg-28mmHg=Net=13mmHg so we would see filtration
How to get the Net Filtration Pressure at the venous end of the capillary?
10mmHg hydrostatic pressure in the capillary that promotes filtration
3mmHgISF hydrostatic pressure that promotes filtration
8mmHgosmotic pressure of the proteins outside of the capillary that promotes filtration
=21mmHg total promoting filtration
-28 plasma oncotic pressure in the capillary that opposes filtration
21mmHg-28mmHg= Net=-7mmHg so we would see reabsorption
What happens to the excess fluid in the arterial side of of the capillary?
How much pressure is this based off of the numbers he gave us?
The lymphatics has to scavenge it
13-7=6mmHg worth of fluid to keep everything balanced. If the lymphatics didn’t scavenge this then we’d have a lot of swelling.
Why don’t we adjust the oncotic pressure in the systemic capillaries at the arterial and venous side to better reflect the proteins staying in the capillary when fluid leaves?
Out in the systemic circulation the capillary is so short and small that there isn’t much of a difference.
This is not the case for the kidney
what is the net capillary pressure?
Would not be unreasonable to use 20mmHg however it ends up being 17.3mmHg d/t the capillary getting larger from front to the end.
What is the average BP in the normal systemic capillary
17.3mmHg
The net filtration pressure on average throughout the entire capillary is ____ but because we have so many capillaries,
0.3mmHg
it is highly dependent on the lymphatic system to scavenge fluids back out so it doesn’t cause us problems
The general capillary is permeable to:
water- 1.00
NaCl- 0.96
The openings between endothelial cells in the capillary allow really small______ to go through and _______
Substances (Na+)
water
Where does NaCl have a really hard time getting through the gap between the endothelial cells ?
Blood brain barrier
albumin is enormous compared to
Na+ so it has a hard time getting through capillary wall
glucose is larger than
NaCl so permeability is a little less for glucose than it is for NaCl
The larger the molecule is, the less _______ the capillary membrane is to that molecule
permeable
Blood comes into the kidney through the
renal artery
What is the bp in the renal artery?
100mmHg
As blood goes through all of the blood vessels in the kidney, the blood encounters a lot of _____ and therefore by the time it exits the kidney from the renal vein the BP is _____
resistance
really low
The amount that a blood pressure is reduced when going through the kidney is dependent on the amount of
vascular resistance it encounters
What is required to move blood through high vascular resistance?
energy
Is there a lot of split points before getting to the afferent arteriole?
Yes
one very important area of this network of blood vessels preceding the kidney is the blood vessel that is sitting right in front of the
glomerular capillaries
They kidneys provide us with a set of capillaries that is going to provide us with an area for a lot of filtration called the
glomerular capillaries
The glomerular capillaries is the first capillary set in a series of
2 capillary beds.
the first is the glomerular capillaries
what is immediately preceding the glomerular capillaries?
afferent arterioles
In front of afferent arterioles are
a couple of larger arteries that split a couple of times to get us to the afferent arterioles.
The afferent arterioles is important in determining what is going to happen to the pressure in the______?
glomerular capillaries
in the glomerular capillaries, pressure defines how much_____ we have
filtration
glomerular filtration rate definition
rate of fluid moving from the glomerular capillary bed to a compartment where we can process what has just been filtered and pick and choose what we want to hang on to like glucose.
glucose is (size)
small
what happens to most of the glucose that gets filtered in the glomerular capillaries?
It gets reabsorbed
The filtration rate is super important for determining
how much processing the kidney is going to be able to do
The afferent arteriole has a high____
resistance
The amount of resistance that is encountered between the renal artery and glomerular capillary is going to give us a BP in the glomerular capillaries of about
60mmHg
why is the bp in the glomerular capillaries(60mmHg) lower than the bp in the afferent arterioles(100mmHg)?
The blood has encountered a lot of resistance to get to the glomerular capillaries which drops the pressure
60mmHg (the bp in the glomerular capillary) is ____ the pressure that we have in a normal capillary. This really high BP in the glomerular capillary is used to
twice
push a lot of fluid out of the glomerular capillaries into a compartment where that fluid can be processed.
All the glomerular capillaries added up that are filtering fluid over the course of a minute give us total filtration rate of
125mL/min
This is all of the glomerular capillaries per minute
what gets filtered in filtration rate?
Small stuff.
we don’t filter very many RBC or large proteins unless
something is really wrong
What are diseases that Smidt suggests can make our renal capillaries not be perfectly healthy?
long term HTN
diabetes
In Ohm’s law:
As resistance goes up, flow goes _____
As delta P goes up, flow goes _____
down
up
If your PISF is 10, how does this effect filtration and reabsorption?
It would oppose filtration and promote reabsorption
If your PISF is -3, how does this effect filtration and reabsorption?
It would pull more fluids out of the capillary i.e. promote filtration and oppose reabsorption
Where are the lymphatic systems found?
hanging around the area near all of our tissues and capillaries
what are the 2 circulatory systems that we have talked about?
lymphatic system
cardiovascular system
where is the entry point for lymphatic fluid to be returned to the cardiovascular system?
Lymphatic ducts at the top of the thorax.
What does a negative net filtration pressure mean for the venous end of the capillary?
That it should favor reabsorption
How does the brain get glucose?
It doesn’t fit through the endothelial cell gaps in the capillaries so we have to have transporters to do this.
The higher the processing, generally, the ____ the organ is going to be able to be
better
