CHAP 1 Flashcards
Units of mass
kg
A mercury barometer measures
atmospheric pressure
An ideal fluid
1.is turbulent
2.has viscosity
3. has a constant density
has a constant density
Viscosity of a fluid is given by
1.strain rate/shear stress
2. sheer stress/ strain rate
- sheer stress / strain rate
A vessel widens to twice its normal radius. If the volumetric flow rate is constant, the speed of flow at the constriction :
1. halfs
2. doubles
3.is 4 times faster
4. is 4 times slower
is 4 times slower
At very low flow rates bloods apparent viscostity :
1. decreases
2. increases
3. stays the same
increases
As the temp of blood increases the viscosity ;
1. remains constant
2. decreases
3. increases
viscosity decreases
A thixotropic fluid is one in which
the shear stress decreases with time under a constant strain
If the pressure differential between the ends of a vessel halves, and the resistance to flow remains the same the flow rate :
1. halves
2.doubles
3. increases by a factor of 16
halves
The Bernoulli eq may simplified to;
p + pgh = constant
A horizontal flow tube has a cross-sectional Area A1 before a stenosis and A2 at it. The difference in P before (p1) and at (p2) the stenosis is governed by a ratio of :
(A1/A2)^2
The Windkessel theory allows us to model;
the change of Pressure with time in the aorta
A large tube branches into 4 smaller tubes with half the radius of the large one. If the total volumetric flow rate in the small tubes equals that in the large tube, the velocity of flow in the small tubes is :
1. half of that in the large tube
2. the same as that in the large tube
3. twice as that in the large tube
the same as the in the large tube
In a blood vessel with elastic walls, compliance is defined as ;
The change of volume of the vessel per change of pressure of the blood
A typical value for hematocrit in a healthy person is
45%
As blood flows through a vessel with decreasing diameter the bloods apparent viscosity:
1. increases
2. decreases
3. stays the same
decreases
Viscosity in a fluid is the equivalent of what in a solid ;
1.stress
2.strain
3. density
4. none of the above
none of the above ( Youngs Modulus)
Darcys Law
Q(flow rate )= change in p/R( resistance)
Autoregulation in a blood vessels means
flow rate is insensitive to pressure variations
What does Poisuilles Law imply would happen to resistance to flow if a vasodilator doubled a blood vessels radius
Resistance to flow would drop by a factor of 16
According to Laplace Law , if the radius of a blood vessels is halved, but the BP stays the same, the tension is the walls of the vessel will;
1. halve
2.double
Halve
As the shear rate of flowing blood increases the viscosity;
1.increases
2. decreases
3. remains the same
decreases
The unit of density is the ;
1. kg m^2
2.kg m^3
3.kg m^-2
4. kg m^-3
kg m^-3
the unit of weight is the
newton
A diver descends from 5m below the surface of the sea to 10m. The gauge pressure on the diver.
(Pgauge=pgh)
1.halves
2.double
doubles
A mercury barometer measures
atmospheric pressure
A Newtonian fluid
1.has no viscosity
2.is thixotropic
3.has a viscosity that depends on temp
4. none of the above
none of the above
a blood vessels narrows to 50% of its normal radius. if the volumetric flow is constant , the speed of flow at the constriction ;
1.halves
2.doubles
3.is 4 times faster
4. is 4 times slower
is 4 times faster
The hydrostatic pressure due to column of fluid is
is proportional to the density of the fluid
According to Poiseuille law the relationship between the pressure differential between the ends of the tube and the flow rate in it is given by :
Q= change in P(8 (pie)R^4/(u )(change in x))
The Fahraeus- Lindquist effects states
The apparent viscosity of blood flowing in a tube from a reservoir decreases with decreasing tube diameter ( in the range 50-500um)
As blood haematocrit increases the viscosity ;
1. decreases
2. increases
increases
For laminar flow in a horizontal pipe, the Bernoulli equation may simplified to ;
1. p+1/2pv^2= constant
2 .p +pgh= constant
3. 1/2pv^2 +pgh =constant
- p + 1/2pv^2=constant
A particular flow has a Reynold’s number of 800. The flow is
laminar flow
Blood is what fluid
Thixotropic fluid
As blood flows through a vessels with decreasing diameter , the bloods viscosity :
1.decreases
2, increases
3. stays the same
decreases
The haematocrit is
the % of blood volume occupied by erythrocytes
A large tube branches into two smaller tubes with half the radius of the large one . If the total volumetric flow rate in the small tubes equals the large tube , the velocity of flow in then small tubes is
1. half of that in the large
2. the same as that in the large
3. twice that in the large tube
twice that in the large tube
If an object of volume V is filled with fluid at pressure p in time, its compilance id given by :
dV/dP
( The change of volume per change in pressure)
The unit of pressure is
N m^-2
A diver ascends from a depth of 8 m below the surface of to a depth of 2 m, the gauge pressure on the diver
decreases by a factor of 4
A mercury barometer measure’s
atmospheric pressure
Viscosity = shear stress/strain rate
A flow tube ( of cross-sectional area A1) with a constriction ( cross -sectional area A2) has a discharge coefficient of;
A2/A1
If we know the the compliance of the aorta and the rate of the flow into the peripheral vessels , the windkessel theory allows us to determine the relationship in the aorta between:
1. V & P
2. V & T
3. P & T
pressure and time
In terms of area and force pressure is calculated by :
P=F/A
Unit of pressure is
Newton per m^2 and
pascal
Gauge pressure is defines as ?
The pressure measured with respect to atmospheric pressure(1atm)
Absolute pressure is
the pressure measured with respect to a vaccum(0atm)
Hydrostatic pressure depends on a fluids;
1. density
2.viscosity
density
The hydrostaic pressure in blood
increases faster with depth than that of water
how many cubic centimeters in 1m^3?
1,000,000
A density of 2g per cubic cm is equal to
2,000kg/m^3
An open tube manometer measures
gas pressure
A barometer is a ?
closed-tube manometer that’s
exposed to atmospheric pressure and so reads
only atmospheric pressure
Unit of pressure
torr
Pascal’s Principle states:
- Where pressure is
applied to an enclosed fluid, it is transmitted
undiminished to every portion of the fluid and the
walls containing it.
Friction in a fluid is caused by
:A) viscosity and turbulence.
B) viscosity and hydrostatic pressure.
C) turbulence and hydrostatic pressure.
D) density and hydrostatic pressure
viscosity and turbulence
Stress id given by what eq:
𝜎 = Force/Area
Stress units?
Pascals
strain is given by the eq;
E=change in l /l
strain units ?
no units
On a stress-strain graph, a steeper curve indicates:
A) a stronger material. B) a stiffer material.
C) a more brittle material. D) a weaker material
A stiffer material
The “plastic region” is the region on the stress-
strain curve where…
deformation is permanent
What is tensile strength ?
it is the max strength that can be applied before the material fractures
The path of flow of an individual particle in a
moving fluid is known as:
Flow Line
If the pattern of the flow lines in a fluid doesn’t change with time, this fluid is said to be:
A) plastic.
B) in turbulent flow.
C) thixotropic.
D) in laminar flow.
in laminar flow
Viscosity of a fluid is given by
sheer stress/strain rate
Choose any or all of the following which are true.
In a Newtonian fluid:
A) the viscosity is zero.
B) the viscosity is constant.
C) the viscosity depends on temperature.
D) the stress/strain-rate relationship is linear
1.The viscosity is constant
2. the stress /strain rate relationship is linear
Which of the following properties does an ideal
fluid possess? (There may be more than one
correct answer.)
A) It has lamiar flow.
B) It has a constant non-zero viscosity.
C) It is irrotational.
D) It has a constant density
it has a laminar flow
it is irrotational
it has a constant density
A blood vessel widens to twice its normal cross
sectional area. If the volumetric flow rate is
constant, the speed of flow where it widens is?
A) is four times slower B) halves.
B) doubles.
D) is four times faster
halves
