hemodynamics

Question 1

enumerate constituents of blood

Answer 1

1. cellular
   
   1. leukocytes (WBC)
   2. thrombocytes
   3. erythrocytes
2. plasma
   
   1. electrolytes
      
      1. Na, Ca, Cl, HCO3, PO4 , protein, K, Mg
   2. non electrolytes
      
      1. colloids- too large to dissolve

Question 2

Compare area and blood volume between the vascular tree compartments

Answer 2

cross sectional area

capillaries>veins>arterioles>arteries>vena cava>aorta

blood volume

veins>arteries>capillaries

Question 3

explain flow dependence on pressure and resistance

Answer 3

F=(P1-P2)/R

can also be flipped to find resistance

R=(P1-P2)/F

Question 4

1. describe poiseuilles law and its ramification
2. what happens to resistance when you reduce the radius from 2 ->1?

Answer 4

1. resistance is inversely correlated ot radius^4
2. 2->1
   
   1. P/16 -> P/1 = the flow decreases and pressure increases

Question 5

what is compliance?

Answer 5

C=V/P, allows an understanding the distendability of a vessel

1. veins have a large Compliance
   
   1. large amount of blood under low pressure
2. Arteries have a low compliance
   
   1. small amount of blood under high pressure

Question 6

Define MAP. How can you calculate it?where is the largest and lowest? How dow arteries maintain their value?

Answer 6

mean arterial pressue

diastolic + (systolic-diastolic)(1/3)

1. pulse pressure = systolic /diastolic

largest=aorta, smallest= inferior vena cava

arteries maintain their value due to high elastance

Question 7

what is the reynolds number? how does it related to flow?

Answer 7

determines the turbulence of the flow.

the increase in reynolds number identifies the increase in turbulence.

laminar<2000….30000<turbulent></turbulent>

<p>Nr=diameter/viscocity: think about a bp cuff</p>

</turbulent>

Question 8

Velocity is ____ proportional to vessel diameter. Put the following in order of blood velocity

Aorta, Vein, capillary

Answer 8

inversely proportional

increasing velocity: aorta>vein>capillary(b/c the total cross sectional area is greatesr here)

Question 9

how is velocity related to vessel size?

Answer 9

V=D/T

• this is inversely proporionate to vessel diameter.
  
  • increase diameter = decrease velocity
  • decrease diamter = increase velocity

Question 10

what is the measurement of bloodcell in the blood?

Answer 10

hematocrit

Question 11

describe the velocity of blood in capillariecapillaries are very slow, b/c they have the greates cross sectional area

Question 12

What structures have an unstressed volume and stressed volume of blood?

Answer 12

1. stressed
   
   1. arteries
2. unstressed
   
   1. veins

Question 13

what is the reason for most of the blood in venous system?

Answer 13

b/c of high compliance of veins

Question 14

what is the flow formula?

Answer 14

flow = change in pressure/ resistance

Question 15

which arrangement has most resistance: series or parallel?

Answer 15

Series>parallel

1. series
   
   1. overall sum of individuals
2. parallel
   
   1. overall is less than the any individual resistance

Question 16

what applies to laminar flow?

how is flow rate considered with this concept?

Answer 16

laminar flow follow poiseulles law, increasing in flow as you move closer to the center.

Question 17

heart murmurs and arterial bruts are detected b/c of what principal?

Answer 17

turbulent flow in the vessel

Question 18

calculate the MAP

pulse pressure= 40

systolic=120

diastolic=80

Answer 18

MAP= diastolic + 1/3(pulse pressure)

80+1/3(40)=93

Question 19

what is the notch in the systolic phase of contraction?

Answer 19

notch in the systolic phase is the dicrotic nothc (incisura). due to a short period of retrograde flow in the aorta just following closure of the aortic valve.