Heamodynamics and microcirculation Flashcards

1
Q

What is Total Peripheral Resistance? TPR

A

resistance to flow of blood in systemic circuit

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2
Q

What does MAP equal?

A

Cardiac output * TPR

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3
Q

What is Darcy’s Law?

A

flow is linearly proportional to pressure difference between 2 points

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4
Q

What is mean velocity?

A

Flow/ Total cross sectional area

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5
Q

What are the 3 types of blood flow in vessels?

A

Laminar- arteries/veins
Turbulent
Single file flow - capillaries

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6
Q

Where does turbulent flow occur?

A

ventricles

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7
Q

What is TPR equation?

A

8nL/ Pir^4
L- tube length r= radius
n= fluid viscosity

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8
Q

What is Poiseuille Law equation for Fluid Flow? Q

A

Pressure difference/Resistance

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9
Q

How are vessels of the same type arranged ?

A

Parallel but aorta/Pulmonary trunk arent

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10
Q

When does total resistance in circuit increase?

A

when series unit added

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11
Q

What is Compliance?

A

Volume/ change in distending Pressure

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12
Q

What is distending pressure?

A

pressure inside minus pressure outside

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13
Q

Why is artery a shallow gradient on Compliance graph?

A

when pressure applied, volume doesn’t increase by much

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14
Q

Why does Vein have large compliance?

A

thin walls and store volume well

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15
Q

What is LaPlace equation for Tension?

A
T= Pt *r/ u
u= wall thickness             Pt= trans mural 
r= radius
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16
Q

What is Trans Mural pressure ? Pt

A

pressure along entire wall

17
Q

What is Autoregulation?

A

adjustment of blood flow to specific tissue

18
Q

How is blood flow changed?

A

diameter of arterioles change

Alter contraction of sphincters

19
Q

How is oxygen a factor of metabolic autoregulation?

A

hypoxia when not enough 02 to meet metabolic demand

20
Q

How is low 02 supply increased?

A

Arteriolar smooth muscle vasodilate

21
Q

What happens in vasodilation?

A

resistance decreases so inc. blood flow so inc. 02

22
Q

What metabolic products diffuse into surrounding tissue and relax smooth muscle?

A

CO2
H+
Adenosine
K+

23
Q

What substances in endothelium mediate vasodilation in smooth muscle?

A

Prostacyclin

Nitrogen oxide- Endothelium derived relaxing factor

24
Q

What happens when Perfusion Pressure increases?

A

inc. stretch of smooth muscle> constriction>inc. Resistance so decreased flow then NEG. feedback

25
What is long term autoregulation of low 02 delivery?
increase Microcirculatory vessels | enlargement of vessels
26
What is an example of when long term autoreg.?
high altitudes
27
What do clefts in capillary endothelium allow?
hydrophobic solutes | water/ ions
28
How is exchange of fluid between capillaries and tissues?
- hydrostatic pressure highest at arterial end | - net osmotic pressure gradient favours fluid absorption by capillary
29
What is net fluid movement?
- fluid out at arterial end | - fluid in at venous end
30
What is lymph ?
fluid with white blood cells and waste
31
What are lymph nodes in the head?
Parotid Submental Submandibular
32
What carries excess fluid from capillary beds?
lymphatic vessels w/ smooth muscle to venous system
33
What does right lymphatic duct drain into?
internal jugular vein
34
What does left lymphatic duct drain into?
Subclavian vein