Lecture 1-16 Flashcards
Cardiac
What is renal clearance?
(A volume of plasma cleared of a substance) / (time)
What is GFR?
Filtration capacity of the kidney
The clearance of what compounds reflect GFR?
Inulin
Creatinine
What is free water clearance?
CH2O
(Volume of water removed from the body) / (time)
T/F: free water clearance includes electrolytes
F
It does not include electrolytes
Increasing ADH = _________ free water clearance
decreasing
Decreasing or the absence of of ADH = _________ free water clearance
increasing
The normal systemic pressure values are:
Systolic: 120 mmHg
Diastolic: 80 mmHg
MAP: 93.33 mmHg (or about 100 mmHg)
MAP =
Diastolic + (1/3)(Systolic - diastolic)
The systemic circulation starts at the ________ and ends at the _________
Aorta
R atria
What is the MAP in the Aorta?
100 mmHg
What is the pressure is the R atria?
0 mmHg
How does being sick effect the pressure in the R atria?
Increases it
What are your highest resistant blood vessels in both the systemic and pulmonary circuit?
Arterioles
What is the blood pressure at the arterial and the venular end of the capillaries? What is Delta P?
30 mmHg
10 mmHg
20 mmHg
What is the BP at the start of the venules?
10 mmHg
The pulmonary circulation starts at the _________ and ends at the _____________
Pulmonary arteries
L atria
What is the Pulmonary artery pressure?
mPAP= 16 mmHg
systolic = 25 mmHg
diastolic = 8 mmHg
What is the pressure at the L atria?
2 mmHg
What is the Delta P of the pulmonary circulation?
14 mmHg
16 -2
What is the Delta P of the systemic circulation?
100 mmHg
100 - 0
Describe pressure upstream and downstream of the high resistance area (chokehold)
Upstream: higher
Downstream: pressure drops as it goes through high resistance area. This is to help blood flow through the area.
The closer we are to the source of the blood, the ______ the pressure
higher
Pulse pressure (PP) =
SP - DP
what is aortic PP?
40 mmHg
Describe PP through the systemic circuit
Drops while going through high resistance areas (arterioles) and stays down
Widen in the large arteries due to walls not being stretchy/stiff vessels
Compare the PP in the femoral artery in the aorta
PP is higher in the femoral artery because it is a large artery with stiff vessels.
The aorta is stretchy and can accommodate a lot of blood
Describe the aorta
- It is stretchy
-Has a wide opening
- Can accommodate a lot of blood coming out of the heart during systole
-During diastole the wall of the aorta come closer together and act as a second pump and pushes blood downstream into the system
How does stretchy vessels affect PP?
Decreases it
T/F: artificial changes in large artery can cause an even greater change in PP
T
What does widening of a PP look like?
Systolic gets higher
Diastolic gets lower
What is the PP in the veins? Why?
Doesn’t have one
Because they are really stretchy
What happens if you give a liter bolus?
Fluid will likey go to the veins because it is a high compliant system that readily takes volume. Veins are really stretchy and can accommodate a lot of volume.
But the blood pressure won’t go up as much.
Increasing stroke volume in stiff vessels will have what effect on PP?
Increase
Describe PP in the pulmonary circuit
Overall it has a low PP because it’s stretchy and very low resistance
low pressures –> low PP
What is the is #1 reason for low pressure in the pulmonary circuit?
low vascular resistance
What is compliance?
Stretchiness
(ΔVolume) / (ΔPressure)
What is low compliance?
Having to use a high amount of pressure to put a small amount of volume into a container.
What is high compliance?
When stretchy, low pressure can be used to put in a lot of volume into a container.
What is an example of a high compliance vessel? Low compliance?
High compliance: veins
Low compliance: arteries
Describe the left and right ventricle pressure during systole and diastole
L: diastole- 2 mmHg
systole- slightly higher than pressure in the aorta to make blood move through it (normal is higher than 120)
R: diastole- low (0 mmHg)
systole- slightly higher than pulmonary art. systolic pressure (normal is higher than 25)
What happens to the aorta with age?
It tightens and hardens –> increases PP
What cell lines the entire CVS?
Endothelial cells
Describe arterioles
Narrow opening
Thick walls
Drives pressure
Consist of smooth muscle
Describe capillaries
Thin walls
Specialized for gas/nutrient exchange
What vessel is only made up of endothelial cells?
Capillaries
What vessel can tighten to impede blood for?
Arteries
Describe the veins
-Very stretchy
-Smooth muscle layer walls that are thinner than arterial walls
-Wide internal diameter that accommodates a lot of volume
Can tighten a bit
The __________ gives veins the ability to adjust the wall tension to keep pressures reasonable for the body
Smooth muscle layers
HR is _____ bpm
72 bpm
SV is _____ cc
70 cc
CO =
SV x HR
CO is ____ L/min
5 L/miin
Velocity =
(Flow) / (Area)
Increased CO = ______ velocity
increased
Increased x-sec/area = _______ velocity
decrease
decrease x-sec/area = ________ velocity
increase
Compare veolcity in the following: Aorta; Venae Cava; Capillaries
Aorta: fastest because it only has one and lowest x-sec
Venae cava: slower velocity than aorta because there’s two and it’s wider
Capillaries: relatively slow because the cross-section is so large because there are so many capillaries
T/F: the velocity of the CO is determined by the x-sec
T
Differentiate between a system in series and a system in parallel. Give example examples.
Series: blood has to flow through a single pathway
Ex) Heart & lungs
Parallel: blood has many pathways to choose from
Ex) systemic circulation & lungs (lungs has some parallel pathways as well)
T/F: gases are water soluble and have problems moving through cells
F
Lipid soluble and can move through cells without problems
The arterial end of the capillary favors _________ and the venous in favors ________
filtration
reabsorption
What is the purpose of the lymphatics?
To take up fluid that isn’t reabsorbed at the Venus in that was filtered at the arterial end of the capillaries
What is an example of a specialized capillary that have tight junctions?
Brain capillaries
For every _________ below a pressure source, the pressure will be increased by _________
13.6 mm
1 mmHg
What is the place in the heart where there’s no effect on gravity called? Where is it?
Isogravimetric point
Middle of the tricuspid valve on the RIGHT SIDE of the heart which is the center of the pressure source
What is another name for the isogravimetric point?
Phlebostatic axis point
What is the anatomical location? of the isogravimetric point?
4th ICS
mid-axilliary line
What is the pressure in the umbilical vein?
+22 mmHg
What is the pressure in the large vein above the knee?
+40 mmHg
What is the pressure in the neck veins? why?
0 mmHg
Neck veins are very compliant; thin walled, expand/compress easily, and wide –> If there were a negative pressure in the neck veins, it would collapse to prevent that negative pressure from building up
What is the pressure in the superior sagittal sinus? why?
This is your cranium & Sinus = large vein
-10 mmHg
The meninges make up the walls of the sinuses. They are rigid, have lots of structures, and not compliant, which allows them to have a subatmospheric pressure
What is a risk when your sinuses are exposed to the environment? why?
Air embolism WHEN YOUR HEAD IS ABOVE YOUR HEART
Due to the sub atmospheric pressure in the superior sagittal sinuses (-10 mmHg) when exposed to air, your sinuses will suck in air from the environment.
Describe the one-way valves and veins
-thin and delicate
-not meant to support large loads for long periods
-Prevents backflow into lower extremities
-Make sure blood is flowing to the heart
-helps to limit effects of gravity
-access shelves and healthy patients
What help support the one-way valves in the veins?
-Contracting and relaxing the skeletal muscles in the legs
-Moving around
What is the pressure in the vein in the upper arm? why?
Between +6 mmHg and +8 mmHg
The column of blood that goes from the arm –> shoulder –> superior vena cava –> heart
T/F: arterial and venous blood have the same weight
T
If you are _________ or __________, you do not have that vertical column of blood to account for additional pressure.
supine
prone
What are the effects of of stretched out veins? what can cause this?
Causes: Standing long periods
Effects: 1-way valves will not work properly and will not prevent back flow –> increased pressure in LE –> increased stretching of vein –> varicose veins –> blood clot risk
What is another word for supine?
Recumbent
Describe the pressure in the foot while supine
Start: 100 mmHg
after arterioles: 25 mmHg
after capillaries: 5 mmHg
T/F: arteries have one-way valves
F
Just open tubes
Describe the pressure in arteries
High internal pressure because they are connected to the aorta, which is a close area to the source of the blood pressure
Why is the arterial pressure in the foot high?
It is a combo of pressure generated by the heart and gravity by the column of blood
Blood pools in your legs when you don’t move which _________ venous return and CO. This could cause you to pass out.
Decreases
Pressure measured in the arm is an _____estimate of pressure in the heart
over
Conductance =
1 / (resistance)
Low resistance = _________ conductance
High resistance= __________ conductance
high
low
What is Ohm’s Law?
V = IR
ΔP =
F x R
Blood flow x vascular resistance
What does distensibility mean?
The ability to expand
Vascular distensibility =
(ΔVolume) / (ΔPressure x original volume)
How is the vascular distensibility and compliance formula similar?
Vascular distensibility adds original volume to the denominator
In vascular distensibility, a larger original volume = ________ distensibility
decreased
In vascular distensibility, a smaller original volume = ________ distensibility
increased
CO is ______ ml/sec
83 ml/sec
___________ is the inverse of resistance
Conductance
What controls blood flow? How is this done?
Changes is tissue metabolism can cause an increase or decrease in flow
This is done by changing vascular resistance by constricting or relaxing the blood vessels diameter/radius
T/F: you need a large change in diameter of a blood vessel to make a major change in blood flow
F
Small changes in diameter can have major changes in blood flow
What is normal SVR values?
800 - 1600
If I decrease the diameter of my blood vessel by 1/2, how much am I decreasing flow by?
1/16
Systemic vascular resistance (SVR) =
What are the units?
((MAP - RAP) / CO) x 80
dynes/sec/cm-5
There is ______ cc is the arterial circulation and ______ cc in the venous circulation.
700cc
2500cc
Describe the behavior of the arteries in the systemic vascular. What happens with sympathetic stimulation with normal volume? Sympathetic inhibition?
low compliace with a steep slope: when you add/subtract small amounts of volume –> big change in pressure
Sympathetic stimulation: with normal volume, pressure gets extremely high
Sympathetic inhibition: pressure will drop
Describe the behavior of the veins in the systemic vascular. What happens with sympathetic stimulation? Sympathetic inhibition?
high compliace with a low slope: when you add/subtract large amounts of volume –> small change in pressure
Sympathetic stimulation: with normal volume, pressure goes up a bit (about 20 mmHg)
Sympathetic inhibition: pressure will drop to 0
