Systemic Circulation and Hemodynamics - Dr. Rogers Flashcards
1
Q
Arteries with P
A
stress volume : high flow and pressure = BP
2
Q
Arterioles
A
moderate P, SM walls
change resistance of blood
3
Q
Capillaries
A
LARGE CROSS SECTION area, exchange site
4
Q
Veins
A
Low P, large V, contract to move blood to arterial side = increase BP
5
Q
greatest cross section area
A
capillaries
6
Q
greatest blood V
A
Veins
7
Q
blood flow =
A
Q= Pressure gradient (delta P)/Resistance (R)
8
Q
Poiseullies law
A
resistance through tube calculation
9
Q
R =
A
(8nl)/ (pi r^4)
n = viscosity
r= radius
l = length
10
Q
if P stays the same how does R decrease
A
increase r of tube
+ increase flow rate to keep P the same
11
Q
How to find viscosity
A
Hematocrit = (RBC: plasma) ratio increased hematocrit (high RBC) ----> lower BF
12
Q
R of 8 tubes in series
A
you add the R for each = TOTAL R
*increases total R
13
Q
R of 8 tubes in parallel
A
this lowers the TOTAL R
* capillaries are like this
14
Q
another thing Q = to
over all heart function
A
Q= CO = (A P - V P) / TPR
15
Q
greatest control of BF
A
TPR in arterioles
16
Q
what increases and decreases TPR
A
Increase : increase sympathetic N to arterioles = vasoconstriction
Decrease : decrease sympatetic N to arterioles = vasodilation
17
Q
how to calculate V of blood in BVs
A
V = Q/CSA
CSA: cross sectional area of vessle
18
Q
highest and lowest V is found
A
highest : As
lowest : capillaries
19
Q
3 things that make BF more likely to be turbulent
A
- high V
- large CSA
- low Viscosity
20
Q
what is Reynolds Number
A
N= pdv/n
p - density
d- diameter
*if N > 2000 = laminar –> TURBULENT transition
21
Q
what does turbulence cause
A
bruits sounds + lesions = arteriosclerosis
22
Q
compliance
A
delta V/ delta P
* shows vascular capacitance
23
Q
highest compliance
lowest complience
A
highest : veins
lowest : arteries
24
Q
what condition can cause decrease in compliance
A
arterosclerosis, causes artery to be unable to distend (systole) and recoil (diastole) as much
25
reason Veins have compliance and what can this lead to is not functioning right
they have SM flexible walls
if the SM constrict (decrease v, same P) = lowers compliance = more blood pushes to arteries
= INCREASE BP
26
where is the biggest pressure drop in the circulation
arterioles
27
before the largest P drop in the circulation, what keeps the P high
Aorta, Large As, Small As all have high P due to Aorta having so much pulsatile action
28
Lowest BP
| Highest BP
DIASTOLE : 80mmHg
| SYSTOLE : 120mmHg
29
Pulse Pressure
SBP-DBP = 40mmHg
| proportional to SV
30
How to calculate the Mean Arterial Pressure (MAP)
1/3 (SBP) + 2/3(DBP)
(DBP) + 1/3(pulse Pressure)
80-40/3 = 93.3mmHg
31
Dichroctic Notch
when aortic valve closes
32
compliance in the practical setting
SV/ Pulse Pressure
33
compliance and Pulse Pressure relationship
as compliance increases the pulse pressure decreases
34
increases R on compliance
decrease in R, lowers P, which increases Compliance
35
what happens in Arteriosclerosis
increase SPB, PP, and MAP
| STAYS SAME : DBP
36
What happens in Aortic Stenosis
decrease SBP, PP, MAP
| STAYS SAME : DBP
37
what does increasing TPR do
Increase in DBP, SBP, MAP
| STAYS SAME : PP
38
3 things about Venous Pressure
1. Low P
2. Large V
3. High Compliance
39
Venocontriction of veins causes
compliance
radius
decrease compliance
small change in r (no large R change)
= increased flow back to heart
40
Venous Pressure waves (3 of them)
A wave
C wave
V wave
* part of jugular pressure
41
A wave
mid P wave to R wave )when A contracts
42
C wave
Ventricular Contraction: (has the bulding of the AV valve up into A
43
V wave
after Ventricles contracted and the AV valves are closed = blood flows into Atrium and stays there
when the valves open the V wave is gone
44
3 parts of microcirculation
1. Arterioles : extensive SM
2. Metarterioles : less SM connecting Arterioles and Venules
3. Capillaries: Branches from the Metarterioles, have precapillary sphincters
45
where are capillaries the largest in exchange and the smallest in exchange
LARGEST : Liver and GI
| SMALLEST : Brain
46
vesicular transport across capillaries when needed are called
caveolae
47
Vasomotion
the metareterioles and precapilllary sphincters constrict in an oscillating way (every few sec) = oscillating BF
* REGULATED BY O2 LEVELS
48
vasomotion and O2 levels
| high and low
high O2 : constriction more often
| low O2 : the sphincters remain open more
49
Starling Equation shows what
1. H2O moving into capillaries (- direction) = ABSORPTION
| 2. H2O moving out of capillaries (+ direction) = FILTRATION
50
4 forces in capillary exchange
1. C = intravascular P
2. i = Extravascular (interstitial) P = Pif
3. P = Hydrostatic P
4. (pi) = Osmotic (oncotic) P
51
what causes absorption into capillaries
| which Ps
1. Interstitial Fluid P *
2. Plasma Colloid P*
3. osmotic (oncotic) P*
52
what causes filtration into capillaries
| which Ps
1. Interstitial fluid colloid osmotic P*
2. Capillary P *
3. Intravascular P (hydrostatic intravascular P)*
53
location of absorption and reabsorption
ABSORPTION : arteriolar end
| REABSORPTION : venous end
54
Capillary Hydrostatic Pressure
Pc
capillary forces fluid OUT
highest at arteriolar end
55
Capillary Osmotic Pressure
(pi)p or (pi)c = colloid osmotic P
| Plasma proteins, NA, K in capillaries force fluid INTO capillaries
56
Interstitial Hydrostatic Fluid Pressure
Pif =
- : force fluid OUT from capillaries
+ : force fluid INTO capillaries
57
Interstitial Osmotic Pressure
(pi)if = force fluid OUT from capillaries
58
equation for net capillary exchange
Kf = [(Pc-Pi) - (pic - pii)]
| * if + that means net FILTRATION
59
capillaries cant reabsorb what
proteins
60
what do lymph carry and what moves substances for them
fluid, proteins, chylomicrons (lipids)
| Muscle contractions
61
what alters Pc
elevated Venous Pressure (heart failure) = increase
62
what alters Pi
restricted lymph flow = increased
63
what alters pic
reduced albumin (starvation, liver failure) = decrease
64
what alters pii
restricted lymph flow or inflammation = i think decrease
65
Acute Control of BF happens how
fast changes in local vasodilation and vasoconstriction
66
when does O2 availability decrease to tissues
high altitudes
pneumonia
CO poisoning
Cyanide poisoning
67
Autoregulation of BF happens when and how
during changes in arterial pressure (metabolically or myogenically)
* fast increase in Arterial P = immediate increased BF
= returns back to normal within minutes
68
Metabolic theory for autoregulation
increased Arterial P = too much O2 and nutrients delivered to tissues = hyperemia
69
Myogenic theory for autoregulation
increased Arterial P = SM stretch in vessel= causes it to constrict = reduce BF back to normal
*no H or N needed
70
Vasodilator theory
low O2 increases vasodilators
71
vasodilators
adenosine, CO2, adenosine phosphate, histamine (from mast cells), K+, H+
Bradykinin (also increase permeability) made from Kallikrein
72
O2 demand theory
not enough O2 = vasodilation of precapillary sphincter in SM
73
Metabolic Control
1. reactive hyperemia : tissue supply blocked for 2min
| 2. Active hyperemia : tissue metabolic rate increased high for 2min
74
vasoconstrictors (4)
1. N + H = NE and E
* mostly NE
2. Angiotensin 2 : increase TPR, decrease NA+ and H2O excretion = increase BP (+ vasoconstrictor)
3. Vasopressin (ADH)
4. Serotonin : from tissue damage or hemostasis
75
ions control BF how for Ca+2
ICM CA+ = vasocontriction
76
ions control BF how for K+
vasodilation
77
ions control BF how for Mg+ ----I SM contractions =
Mg+ ----I SM contractions = vasodilator
78
ions control BF how for H+
vasodilation
79
ions control BF how for acetate and citrate
vasodilation
80
ions control BF how for CO2
some vasodilation (MOST IN BRAIN)
81
SYMPATHETIC EFFECT ON:
1. small a and arterioles
2. Large vessels
3. Heart
1. increase TPR = decrease BF
2. decrease the Blood volume to push blood forward to the heart
3. increase HR and Contractility
82
Coronary BF happens when
during repolarization of the ventricle----> diastole*
| controlled by adenosine + hypoxia, metabolic
83
Cerebral Blood Flow happens when
autoregulated
injury
BP below 50mmHg
under metabolic, PCO2, H+
as BP increases, it vasocontricts (HOWEVER FLOW STAYS THE SAME* when autoregulated
vasodilation + edema
vasoconstriction
84
pulmonary circulation
higher RV and pulmonary A
MAP 15mmHg
* keep arterial P low
85
At rest: blood flow is Skeletal muscle does what and is controlled by
controlled by central receptors + baroreceptors (NE and a-adrenergic)
86
During Exercise: blood flow is Skeletal muscle does what and is controlled by
CO increases, TPR decreases = dilation of BVs
Muscle BV dilation also done by : ATP, adenosine, NO, K+, lactate and Epi--> B-adrenergic R
*hyperemia can happen after
87
rise is body temperature does what to BV flow
a-1-adrenergic R induced causing constriction which is inhibited by SYMPATHETIC ACTIVATION
= vasodilation and movement of vessels closer to skin
88
trauma to skin releases what causing what triple response
HISTAMINE
1. red line
2. red flare
3. red wheal (edema)
