Week 5

Question 1

What is hemodynamics

Answer 1

blood flow, motion and the equilibrium under the action of external forces
study of blood flow or the circulation

Question 2

The cross sectional area of a vein is about _____x that of a corresponding artery.

Answer 2

3-4

Question 3

How much of the body’s blood does the veins contain

Answer 3

2/3rds

Question 4

Veins have lower resistances to flow as compared to arteries. True or false

Answer 4

False– veins and arteries have about the same resistance to flow

Question 5

As the rate of flow increases, the vein becomes _____(more/less) circular , ________ (increasing/decreasing) the resistance.

Answer 5

more, decreasing

Question 6

What’s the power source that pumps blood back up to the heart?

Answer 6

calf muscles

sinusoids of gastro and soleus muscles and deep/superficial veins play a part

Question 7

Closure of the valves in the deep veins decreases the length of the column of blood. What does this do to the venous pressure?

Answer 7

reduces it

Question 8

At rest, blood pools in the legs and is only propelled passively by what? What creates this?

Answer 8

by the dynamic pressure gradient which is caused by the contraction of the LV

Question 9

Contraction on the calf muscles can generate pressures of

Answer 9

> 200mmHg

Question 10

Are there valves in the perforating veins?

Answer 10

Yes

Question 11

What do you call a magic dog

Answer 11

a labracadabrador

Question 12

Do sinusoids empty or fill with blood with relaxation?

Answer 12

fill

Question 13

Do sinusoids empty or fill with blood when contracted?

Answer 13

empty

Question 14

What is it called when red cells stick together which increases the blood viscosity? (slow flow sonographically)

Answer 14

rouleaux flow

Question 15

Viscosity

Answer 15

thickness of fluid. friction of adjacent fluid layers sliding past one another as seen in blood cells travelling through a vessel

Question 16

People who are dehydrated, smokers, in high altitudes, have pulmonary fibrosis are all lower availability of oxygen states. This increases what?

Answer 16

blood viscosity

Question 17

The venous pressure of the lower limbs is comprised of 3 main components:

Answer 17

hydrostatic (gravitational) pressure
residual pressure
muscular and respiratory pressure

Question 18

Hydrostatic pressure

Answer 18

due to height in the venous column

applies when patient is in standing position

Question 19

Residual pressure

Answer 19

main resistance of flow is due to microcirculation

at the venous end of capillaries, the venous pressure supplied by the arterial pressure

Question 20

What acts as an alternate pump to the heart?

Answer 20

calf muscles

Question 21

When we fill our lungs with air, what happens?

Answer 21

pressure in thorax decreases
abdo pressure increases
flow from lower limbs is impeded

Question 22

Arterial hemodynamics:

Answer 22

waveform reflects cardiac cycle
not affected by respirations
high pressure 
pulsatility: according to vascular bed it supplies
has a pulse

Question 23

Venous hemodynamics:

Answer 23

waveform reflects the respiratory movements
phasicity
low pressure
pulsatility: according to proximity to heart
no pulse

Question 24

Where do we start seeing not much spontaneous flow?

Answer 24

distal to femV

Question 25

What affects venous flow?

Answer 25

``` exercise cardiac function calf muscle pump respiratory variations competent venous valves venous pressure ```

Question 26

Risk factors for hereditary blood disorders?

Answer 26

antithrombin deficiencies elevated clotting factors plasminogen deficiency prothrombotic disease

Question 27

What's the main component of a clot?

Answer 27

plasma breaking down fibrin

Question 28

Risk factors for acquired blood disorders?

Answer 28

``` age, obesity advanced malignancy recent surgery trauma pregnancy OC use immobilization ```

Question 29

What's Virchow's triad? | this is the three broad categories thought to contribute to thrombosis

Answer 29

endothelial damage venous stasis hypercoagulable state

Question 30

What's the signs and symptoms of a DVT?

Answer 30

lower extremity swelling pain positive Homan's sign

Question 31

What is a + Homan's sign?

Answer 31

pain on forced dorsiflexion of foot

Question 32

D-dimer assay-

Answer 32

measures fibrin degradation products that accumulate in the blood when thrombus forms

Question 33

If the d-dimer is negative

Answer 33

DVT is unlikely

Question 34

What are some d-dimer false positives?

Answer 34

patients over 80, hospitalized, pregnant, and with cancer

Question 35

Prothrombin time

Answer 35

time it takes for plasma to clot affected by disseminated intravascular coagulation (DIC), PTT, unexplained bleeding or clotting used to evaluate hemostasis (process the body uses to form clots and stop bleeding)