introduction Flashcards
whats the main 2 functions of cardiovascular system?
1- delivering O2 and nutrients to the tissues
2- removing co2 and wastes products from tissue
what are the other side functions of cvs?
1- delivering hormones from their glands and their site of action
2- regulating body temperature
3- maintaining adequate blood supply in the body in various stress conditions
whats the unit to measure Cardiac output
ml/minute
whats the equation of cardiac output
SV x heart rate
which pump is the systemic and which is pulmonary?
right pump = pulmonary
left pump = systemic
whats the relation between venous return and cardiac output in a steady state?
in a steady state :
Cardiac output = venous return
whats the normal distribution of cardiac output in the body systems?
25% = skeletal muscle
25% = renal
25%= GIT
15% = cerebral
5% = coronary
5% = skin
whats the systolic and diastolic pressure in the heart and how are they produced?
systolic pressure is formed when the left v contracts
Diastolic pressure is formed in the aorta by the elastic fibers coiling back.
which vessels carry the deoxygenated blood from the heart to the lung
pulmonary ARTERY
which vessels carry the oxygenated blood from the lung to the heart
pulmonary VEINS
whats the description of the arteries flow
high pressure high resistance
whats the function of arteries?
transfer blood from the heart to tissues under high pressure
Elastic arteries are near the heart
muscular arteries are near the away from the heart
whats the function of arterioles?
control blood before entering the capillaries , considered to be the last small branches of conduit arteries , HAS THE HIGHEST RESISTANCE
whats the function of capillaries?
exchange of fluids and nutrients and hormones, between interstitial spaces
whats the function of venules?
collect blood from capillaries before gradually coalescing into larger veins
whats the function of veins?
transport the blood from the tissue back to the heart under low pressure, also has the most blood in a point of time –> major reservoir of blood
whats the description of veins flow?
low resistance low pressure
whats is the definition of compliance?
ability of vessel to stretch
high compliance = easily stretched
Low compliance = hardly stretched
whats the equation of compliance?
compliance = change in volume ( delta v)
————————————————-
change in pressure ( delta p)
what is capacitance?
capacity of a vessel to hold blood ( capacity )
which vessel has the highest compliance and capacitance?
VEINS, has the highest compliance –> easily stretched
since its easily stretched it can hold a lot of blood –> high capacity —> highest capacitance
which vessel has the lowest compliance and capacitance?
Arteries —? has the lowest compliance –> cannot be stretched easily and since its not easily stretched it cannot hold a lot of blood–> low capacity
in arteries what could a small change in volume do to the pressure?
a small change in the volume would lead to a massive change in pressure, why? cuz they have low compliance and capacitance? cannot accommodate the changes.
in veins what could a large change in volume do to the pressure?
in veins a large change in volume would lead to no or small change in pressure , why? cuz they have high compliance and capacitance ? and can accommodate the changes?
what are the effects age and sympathetic effect on volume pressure curves?
increase vascular smooth muscle tone and increase pressure at each volume
whats ohm law?
Flow (Q) = change in pressure ( delta P )
——————————————–
Resistance (R)
delta P = change in pressure gradient between the 2 ends of the vessel
whats the laminar flow?
its the smooth , silent normal flow of the blood
wheres the fastest velocity point in laminar flow ?
the maximum is the center point , in the middle
wheres the slowest velocity point of laminar flow? and what causes it
the minimum velocity point is the more peripheral near the walls and its CAUSED BY ADHERANCE MOLECULES
whats the turbulent flow?
the abnormal flow that happens due to obstruction and its noisy, with low velocity
what could cause turbulent flow?
anemia - due to decrease viscosity
vascular aneurysm
fistula -> ABNORMAL ARTERY VEIN CONNECTION
whats the equation of reynold number (NR)
Velocity x diameter x density
NR = ——————————————
viscosity
According to reynold number when is laminar flow diagnosed ?
when reynold number is LESS than 2000
According to reynold number when is turbulent flow diagnosed ?
when reynold number is MORE than 2000
whats the difference between velocity and flow?
Velocity is speed, distance over time –> cm/s
Flow is volume over time –> mL/s
whats the equation of velocity?
velocity = Flow
————————–
cross section area
which area has the largest cross section and slowest velocity?
capillaries
which area has smallest cross section area and Fastest velocity
aorta
how to calculate resistance from OHMS law
since Q = Delta P
———————-
R
So
R = Delta P
————————
Q
Q = flow
Delta P = change in pressure gradients
R = resistance
whats poiseuille law for the resistance?
R = 8 x N x L
————————-
Pi r^4
R= resistance
N= viscosity of blood
L= length of the vessel
r = radius
whats the main factor that affects the resistance according to poiseuille?
its raidus since its to the power 4
if you decrease the radius by half it will increase the resistance by 16 times
If you double the radius it will DECREASE the resistance by 16 times
what are things that could lead to vasoconstriction ?
- Increased myogenic activity by sympathetic
- Oxygen
-Endothelin
-Vasopressin
-Angiotensin 2
what are things that could lead to vasodilation?
- Carbon dioxide
-nitric oxide
-Histamine
-Heat
whats a series resistor system and how to calculate total resistance?
a resistance system where the resistances are back to back and to calculate you add all of them for example :
Rt= R1 + R2 + R3
what are the few characteristics of the series system?
1- the total resistance is always greater than all individual resistance
2- adding a resistor in the series will increase the total resistance
3- the flow is equal in all points
4- pressure decreases according to the resistance it has to overcome - the pressure is lost when overcoming a huge resistance
where is the largest drop in pressure?
in arterioles cuz it has the highest resistance
what are the vessels that arranged in series?
arteries -> arterioles -> capillaries -> venules > veins
what is parallel resistance system and how its calculated
a system where the resistance is in a parallel position and its calculated by adding the reciprocals of the resistance =
Rt= 1/r1 + 1/r2 + 1/r3
whats are the few characteristics of parallel resistance system?
1- the total resistance is always Less than the individual
2- if you add an extra parallel resistance it will DECREASE the TOTAL RESISTANCE
3- IF you increase an already EXISTENT resistance this will increase the total resistance
4- flow in each resistance is adjusted alone and independent
where you can find parallel resistance system?
systemic circulation : coronary, cerebral, renal , GIT, etc
in poiseuille law the viscosity ? what its viscosity and how its increased? whats its measurement
viscosity is the stickiness of fluid
its measured by hematocrit usually 40
its determined by the rbc , more rbc = more viscosity
whats the equation of pressure?
pressure = force
————–
Area
what is blood pressure?
force exerted by blood against vessel wall
whats systolic pressure?
the peak aortic pressure , its caused during the ejection of blood and by the left ventricle usually 120 mm ( NOTE THAT THE NORMAL AORTIC PRESSURE IS 80 SO THE VENTRICLE NEED TO BE MORE THAN THAT TO OPEN THE AORTIC VALVE SO ITS 120 )
whats diastolic pressure?
the minimum pressure in the aorta caused by the recoil of elastic fibers usually 80
what is Pulse pressure?
systolic pressure - diastolic pressure usually is 120-80 = 40
whats Mean atrial pressure? and how to calculate it? and should it be constant or no?
MAP is the pressure required for prefusion and it SHOULD BE CONSTANT , there are 3 ways to calculate it :
MAP = CO x TPR ( total peripheral resistance )
OR
MAP =diastolic pressure + 1/3 pulse pressure
OR
MAP = 2/3 diastolic pressure + 1/3 systolic pressure
why? cuz diastolic is longer than systolic period
how is MAP is maintained in cases of hemorrhage and exercise ?
in hemorrhage theres decrease in CO but the TPR is increased to compensate
In exercise theres decreased TPR by vasodilation to compensate for the increased CO.
in a systemic atrial pressure graph what does the dicrotic notch indicate (Incisura ) ?
closure of aortic valve?
whats the major regulating factor for the Atrial SYSTOLIC pressure?
SV – > high sv –> is always due to decreased ESV by increased pressure
Compliance of artery –> less compliance requires more pressure to stretch
whats the major regulating factor for Atrial DIASTOLIC pressure ?
total peripheral resistance TPR –> if the resistance is low it doesnt require much diastolic pressure.
what are the major regulating factors of pulse pressure?
since pulse pressure is systolic - diastolic
anything that regulates these 2 will control pulse pressure so :
SV
Compliance
TPR
whats the damping of pressure pulse ?
its the progressive diminishment of the pulse pressure in the peripheral circulation
why damping of pressure pulse happen?
cuz the resistance difference, and the pressure decreases when overcoming high resistance
in veins its low resistance so less pressure
- the compliance difference in vessels? we said that compliance is important for regulating of systole pressure and so it is for pulse pressure
and veins has high compliance so less pressure required to stretch
what are the 2 mechanisms for measuring blood pressure?
direct method —> insert catheter to the blood vessel
indirect method –> auscultatory method
what happens to the pressure when you are older?
it increases due to the changes that occur to the regulating mechanisms :
1- kidney –> which is responsible for long term regulation
2- arteries they lose elasticity which will cause reduced compliance and that will require increases systolic pressure to stretch the arteries
which part of the circulation has the highest flow velocity
aorta and arteries due to small cross sectional area
which part of the circulation has the highest volume?
venules and veins ( high compliance and capacity )
which part of the circulation has the highest pressure systolic and diastolic?
aorta and arteries -> less compliance requires more pressure to stretch
which part of the circulation has the highest resistance?
arterioles –> largest drop in pressure happens them.
