CGIER 9 - CVS 4

Question 1

What does the Bernoulli principle state?

Answer 1

Bernoulli’s Equation states that the work done on a fluid as it moves from one place to another is equal to the change in its mechanical energy.
∆𝑊= ∆𝑃𝐸+ ∆𝐾𝐸
(work energy relation)

Question 2

When a liquid flowing through a pipe of two regions of different diameters, the velocity of the liquid will ____.

Answer 2

change

Question 3

The change in velocity involves an acceleration, a, which means there is a…

Answer 3

net force acting upon the liquid (F = ma).

Question 4

𝑃+1/2 𝜌𝑣^2+𝜌𝑔ℎ=𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
What does each represent?

Answer 4

Where P is the external pressure, 1/2 𝜌𝑣^2 is the kinetic energy and 𝜌𝑔ℎ is the fluid pressure (potential energy).

Question 5

Bernoulli’s Equation can only be used given the following assumptions:

Answer 5

1. Fluid is incompressible (i.e. its density does not change).
2. Fluid is non-viscous (i.e. no appreciable frictional effects).
   3.Fluid flow is streamline.
   4.Flow velocity at a fixed point does not change rapidly (i.e. steady state conditions apply).
   i.e. Bernoulli’s Equation is only an approximation

Question 6

If Velocity Increases –>
If Velocity Decreases –>

Answer 6

Pressure Decreases
Pressure Increases

Question 7

P + 𝜌gh is the _______ term.

Answer 7

pressure

Question 8

½ 𝜌v2 is the ______ term

Answer 8

velocity

Question 9

An aneurysm is a

Answer 9

swelling in a blood vessel which may rupture – can be fatal.

Question 10

Aneurysms usually occur due to a…

Answer 10

weakness in the wall of the vessel which ‘bubbles’ due to the fluid pressure within the vessel.

Question 11

Once an aneurysm starts, it will continue to grow until:

Answer 11

1. It cannot grow anymore because of an obstruction (bone or tissue obstruction or stent),
2. The elastic tension in the vessel wall is large enough to contain it,
   3.It bursts.

Question 12

The fact that the aneurysm continues to grow is a direct consequence of the Continuity Principle and the Bernoulli Principle, why?

Answer 12

1. Since the fluid pressure acts perpendicular to the surface, it will cause the vessel wall to swell in the region of weakness
2. As the cross-sectional area gets bigger, the velocity decreases (Continuity Equation).
   As the velocity decreases, the fluid pressure increases (Bernoulli Principle).

Question 13

A stent is a…

Answer 13

cylindrical ‘tube’ which can be placed within the lumen of the blood vessel at the location of the aneurysm.

Question 14

Detected aneurysms may be treated by clamping the blood vessel or using a…

Answer 14

stent

Question 15

One-way valves in blood vessels passing through muscle help in…

Answer 15

venous return.

Question 15

A stent will contain the blood (allowing it to flow through it), but stop…

Answer 15

the fluid pressure from acting directly on the vessel wall where the aneurism exists.

Question 16

High blood velocity past the constriction causes low BP in left vertebral artery. A reverse (downward) blood flow can then result in…

Answer 16

Subclavian Steal Syndrome which in turn results in Transient Ischaemic Attack.

Question 17

Vessels in circulatory system suffers one of two fates:

Answer 17

1- Aneurysm
2- Obstruction due to clot

Question 18

The value of g is critical, and if the body is exposed to external accelerations, then the pressure…

Answer 18

in each of the arteries will change [by r(g +/- a)h if the acceleration is in the up or down direction] – this is directly analogous to Effective Weight.

Question 19

As the main fluid flows from the wider tube into the constricted tube, its flow speed…

Answer 19

increases because the cross-sectional area has decreased (Continuity Principle). Consequently, the fluid pressure in the constricted region decreases.

Question 19

Q
One-way valves keep blood from…

Answer 19

flowing backwards.

Question 19

If the vertical tube is connected to a reservoir of other fluid, then this will be ‘entrained’ into the main fluid provided the…

Answer 19

pressure in the constricted region is lower than that in the fluid reservoir.

Question 20

Defective valves means…

Answer 20

pooling of blood in leg veins (Varicose )

Question 21

The use of the Bernoulli Principle to draw a second fluid into the initial fluid is called…

Answer 21

entrainment.

Question 21

In aspirators, if the pressure decreases below normal atmospheric pressure, then…

Answer 21

air will be ‘sucked in’ through the vertical open tube.

Question 21

A vacuum aspirator pump is essentially a…

Answer 21

pipe with a narrowing in it.
As air flows through that narrowing, it speeds up and its pressure drops, A tiny opening in the side of the narrowing allows water or air to enter the high-speed flow.