Week 5

Question 1

Pressure is used for ___.
In solids, the quantity force per unit area is referred to as ___.

Answer 1

Pressure is used for gases or liquids
In solids, the quantity force per unit area is referred to as stress.

Question 2

Pressure is measured in

Answer 2

Newton’s per square meters, i.e. Pascal.

Question 3

1 mmHg is equal to

Answer 3

0.133 kPa

Question 4

Fluid -

Answer 4

A substance in the liquid or gas phase.

Question 5

For fluids at rest, the shear stress is

Answer 5

zero

Question 6

Intermolecular bonds are strongest in

Answer 6

solids

Question 7

Intermolecular bonds are weakest in

Answer 7

gases

Question 8

Body of fluid is not able to resist a shearing force exerted on its surface, so it…

Answer 8

must keep deforming when subjected to it.

Question 9

When the pressure in the cuff exceeds the systolic pressure,

Answer 9

there is no blood flow to the lower arm and, consequently, no sounds.

Question 10

When the pressure in the cuff is lowered with the release bulb to just below the systolic
pressure

Answer 10

there is intermittent flow, which is turbulent and produces gurgling sounds called the Korotkoff or K sounds.

Question 11

Korotkoff or K sounds -

Answer 11

gurgling sounds produced by intermittent turbulent flow when the cuff P is lowered just below systolic P

Question 12

As the cuff pressure is lowered further, K sounds…

Answer 12

get louder and then lower and are heard until the cuff pressure decreases to the diastolic pressure

Question 13

Blood flow is not interrupted when the cuff P is less than the diastolic pressure

Answer 13

and the K sounds cease because the blood flow is no longer turbulent

Question 14

The onset of the K sounds denotes

Answer 14

the systolic blood P

Question 15

The end of the K sound denotes

Answer 15

the diastolic P

Question 16

The brain contains approximately how much cerebrospinal fluid (CSF)?

Answer 16

150 cm3

Question 17

Increased pressure causes the skull to

Answer 17

enlarge (hydrocephalus)

Question 18

The pressure in normal eyes ranges

Answer 18

from 1.6 to 3 kPa

Question 19

glaucoma -

Answer 19

the pressure increases in the eyeball, it can restrict the blood supply to the retina and it affects vision.

Question 20

Cystometry

Answer 20

clinical diagnostic procedure which is used to measure forces in the bladder

Question 21

The result of cystometry

Answer 21

cystometrogram, which plots the volume of liquid
against intravesicular pressure

Question 22

Law of Laplace

Answer 22

gives the relation between the pressure within the lumen of a vessel (ΔP), the tension in the wall (T) and the vessel radius (R):
T=deltaP*R

Question 23

equation of continuity

Answer 23

statement of the conservation of mass during flow

Question 24

What can we understand from equation of continuity?

Answer 24

In steady state, the same mass flows into a volume and leaves it

Question 25

Bernoulli’s equation relates blood pressure (P), and blood flow velocity (v)

Answer 25

If pressure losses due to friction or turbulence are neglected, Bernoulli's equation states that: “the sum of fluid mechanical energy (Pressure energy), P, fluid kinetic energy ½ρv2, and fluid potential energy, ρgh, stays constant"

Question 26

Bernoulli's law tells us that when a fluid particle decelerates pressure

Answer 26

increases

Question 27

Bernoulli equation clinical applications

Answer 27

It is used for estimating the severity of an aortic or mitral valve stenosis, arterial stenosis and aneurysms

Question 28

three components of the cardiovascular system

Answer 28

1. Blood is the vehicle for transport 2. The circulatory system is the distribution system and consists of a series of branched blood vessels. 3. The heart is the four-chambered pump composed mostly of cardiac muscle that enables this circulatory flow

Question 29

How much time f/ the average RBC to make 1 complete cycle of the body in a typical adult w/ 64 kg of mass?

Answer 29

56 sec

Question 30

systole lasts for about 1/3 of the cycle, the mean blood pressure is a weighted sum

Answer 30

P mean = (P sys + 2P dias)/3

Question 30

arterial pulse pressure (P pulse)

Answer 30

difference in pressure of 40 mmHg between systole and diastole

Question 31

stenotic resistance ___ with flow

Answer 31

stenotic resistance increases with flow

Question 32

where does much of the pressure drop in the arterial system?

Answer 32

in the arterioles (small arteries) and the capillaries

Question 33

flow of blood in arteries is affected by (3):

Answer 33

- changes in the heart beat rate - the volume pumped per beat (stroke volume) - changes in the arteries themselves that control their diameters by chemical and neural mechanisms

Question 34

two physical attributes of blood vessels in steady state:

Answer 34

1. They have a resistance to flow, and so they need a pressure difference along the length of the vessel to drive the blood flow. 2. They have a compliance in response to a distending pressure.

Question 35

resistance vessel -

Answer 35

rigid vessel with constant volume V flow rate of the resistance vessel is affected by the pressure drop inside the vessel Arterioles, capillaries, and venules act like resistance vessels

Question 36

compliance vessel -

Answer 36

elastic vessel that has no noticeable resistance volume of the compliance vessel is affected by the pressure difference between the inside and outside of the vessel aorta, large arteries and large veins are much like compliance vessels

Question 37

stenosis is quantified by

Answer 37

the ratio As/Ao, called the area ratio same expression as percentage of error: **(1 - A_s/A₀) * 100**

Question 38

linear term (first term) in the pressure drop-flow equation accounts for

Answer 38

viscous losses within the stenosis

Question 39

quadratic term (second term) in the pressure drop-flow equation accounts for

Answer 39

losses due to turbulence

Question 40

severe stenoses (area occlusion higher than 85%), what losses dominate?

Answer 40

turbulent losses

Question 41

Law of Laplace relates what?

Answer 41

relates **transmural P** (diff in P b/w 2 sides of a wall) WITH **wall stress** T = ΔP * R

Question 42

Equation of continuity:

Answer 42

statement of the conservation of mass during flow When a fluid of a given density ρ, moves with average speed v, in a tube of cross-sectional area A, the product ρAv is constant. Q = A1v1 = A2v2

Question 43

BERNOULLI’S EQUATION

Answer 43

relates blood pressure (P), and blood flow velocity (v); E law; EXPRESSES THE CONSERVATION OF E IN THE FLOWING BLOOD v HIGH - P low

Question 44

LAW OF POISEUILLE

Answer 44

describes the relation between pressure drop, ΔP, and fluid flow, Q, under steady flow conditions Q = 𝚫𝐏𝝅𝒓𝒊 / 𝟖𝜼𝒍