Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HMS Homeostasis I > Flow through tubes > Flashcards

Flow through tubes Flashcards

1
Q

Ohm’s Law

A

ΔP = F x R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Pouiselle’s Law

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In laminar flow, pressure gradient is proportional to flow by the relationship ___.

In turbulent flow, pressure gradient is proportional to flow by the relationship ___.

A

In laminar flow, pressure gradient is proportional to flow by the relationship:

ΔP ∝ ΔF

In turbulent flow, pressure gradient is proportional to flow by the relationship:

ΔP ∝ ΔF2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Resistance of tubes in series vs in parallel

A

In series: Sum of resistances

In parallel: RT = ( 1 / R1 + 1 / R2 + 1 / R3 . . . 1 / Ri )-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The higher Reynold’s number, . . .

A

. . . the more likely you are to have turbulent flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

As chronic bronchitis progresses. . .

A

. . . patients must utilize their accessory breathing muscles more and more to overcome the increasing resistance of their airways and support laminar air flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

As a fluid moves along a tube, . . .

A

. . . the pressure of the fluid will drop due to the work it is doing to overcome the resistance of the tube.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In respiratory physiology, flow is represented by __.

In cardiovascular physiology, flow is represented by __.

A

In respiratory physiology, flow is represented by V.

In cardiovascular physiology, flow is represented by Q.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Characteristics of laminar flow

A
  • All flow in the tube is parallel to the long axis of the tube (radial flow)
  • Fluid traveling at the center of the tube moves more rapidly than fluid near the wall of the tube
  • Pressure difference between two points is directly proportional to the flow (double the pressure difference → double the flow).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Characteristics of marginally laminar / disturbed flow / transitional flow

A
  • Characteristics of both laminar and turbulent flow
  • Flow is generally laminar but there are eddies generated at angles to the long axis of the tube, usually at branch points, changes in direction of the tube or regions of irregularity in the wall.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Turbulent flow

A
  • Flow occurs both parallel to the long axis of the tube and perpendicular to the axis (axial flow).
  • Often results in the creation of noise when the fluid hits the wall of the tube (wheezing, murmurs, bruits)
  • With turbulent flow, the pressure difference between two points is proportional to the square of the flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Reynold’s Number

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Bernoulli’s Equation

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Continuity Equation

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

viscosity

A

force per unit area resisting flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Wheeze vs Murmur vs Bruit

A

Wheeze : respiratory

Murmur : cardiac

Bruit : vascular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The resistance of the small airways of the lung does not inhibit our ability to breathe because. . .

A

. . . these airways are in parallel, not in series.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Under normal circumstances the greatest resistance to airflow resides in. . .

A

. . . the medium sized bronchi.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is it good that the velocity of air in the lungs is minimized in the smallest vessels?

A
  1. This is where gas exchange takes place
  2. It reduces Reynold’s number, preventing turbulent flow in these tubes with narrow diameters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The lowest total cross-sectional area in the vascular system is in the ___.

The highest total is in the ___.

A

The lowest total cross-sectional area in the vascular system is in the aorta.

The highest total is in the capillaries.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Vacsular pressures

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

mean arterial pressure

A

the mean pressure in the aorta just after the blood exits the left ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

central venous pressure

A

pressure at the right atrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

ΔP for circulatory system

A

Mean arterial pressure - Central venous pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

ΔP = flow x resistance in the circulatory system

A

MAP – CVP = Q x SVR

SVR = systemic vascular resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

pulmonary vascular resistance

A

resistance of the pulmonary system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Bernoulli’s principle applied to pressure at different points in a continuous tube of varying diameter

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Major determinants of pulmonary flow resistance

A
  • Smooth muscle tone
  • Elastic recoil of lung
  • Tethering of alveolar connective tissue to pleura
29
Q

Resistance to fast vs slow breathing

A
30
Q

Hysteresis

A

The phenomenon in which the value of a physical property lags behind changes in the effect causing it.

31
Q

Airway smooth muscle tension exhibits ___ during the inhalation/exhalation cycle for any given level of autonomic nervous system tone.

A

Airway smooth muscle tension exhibits hysteresis during the inhalation/exhalation cycle for any given level of autonomic nervous system tone.

That is, the airways are wider at a given lung volume when that lung volume is reached via deflation as opposed to via inflation. This is explained by stress relaxation. If you stretch tissue and hold it in that stretched position momentarily, the elastic forces will relax a bit.

32
Q

Transmural airway pressure

A

Pairway - Ppleura

Always positive at rest due to the resting negative pressure of the pleura.

33
Q

Distending pressure

A

Any positive transmural pressure. Called distending because it keeps the lung in its distended position.

Distending pressure is lost in pneumothorax or with other forms of lung collapse.

34
Q

During exercise when expiratory muscles are recruited to evacuate air, the pleural pressure during expiration. . .

A

. . . is often positive. If it is higher than the airway pressure, then the transmural pressure is positive, and the airways may collapse. In healthy individuals, it is the smooth muscle and cartilage surrounding the airways that prevents this.

35
Q

Why is pressure in the alveoli during inspiration lower than atmospheric pressure?

A
  1. The velocity of particles in the alveoli is increased by the continuity equation, since they are being forced through a smaller tube. By Bernoulli’s equation, this corresponds to a decrease in mural pressure.
  2. The particles are doing work on the walls of the airway to overcome resistance as they travel through the airways.
  3. The terminal airways are more likely to have turbulent flow due to their smaller diameter, and this means that to sustain flow pressure must decrease. You can also think about this one in terms of the work done on the walls of the vessel by a turbulent fluid (ex, the energy of the sound waves we hear as wheezing)
36
Q

Equal pressure point

A

The point in a tube containing a moving fluid where the transmural pressure is zero.

37
Q

Alveolar pressure equation

A

Palveolus = Pelastic recoil + Ppleura

38
Q

TLC

A

Total lung capacity - the maximal volume someone can breathe in before they cannot breathe in anymore

39
Q

Residual volume

A

The volume left after someone fills their lungs to the TLC and then breathes out as hard and fast as possible until they cannot anymore

40
Q

Vital capacity

A

TLC - RV

41
Q

Volume-Flow diagram

A
42
Q

Conduit vessels

A

Transport quickly to and from regions of the body (aorta, vena cavae)

43
Q

Distribution vessels

A

Distribute blood specifically to and from particular organs

44
Q

Resistance vessels

A

Account for the bulk of the resistance in circulation (the arterioles)

45
Q

Exchange vessels

A

Allow for the movement of gases, fluids, and nutrients into and out of the blood (capillaries)

46
Q

Capacitance vessels

A

Vessels that serve as a reservoire of blood. Capable of holding large amounts of volume at low pressure, characteristic of structures with high compliance

(C = ΔV/ΔP)

47
Q

___ is an important regulator of venous return

A

venoconstriction is an important regulator of venous return

48
Q

Vaso vasorum

A

Tiny blood vessels that penetrate into the walls of muscular blood vessels to supply their tunica media.

49
Q

___ bolsters blood pressure between ventricular contractions.

A

Elastic recoil of the aorta bolsters blood pressure between ventricular contractions.

50
Q

Continuous capillaries

A

Capillaries that allow little to no exchange across tight junctions of the endothelial cells. In these cells the basement membrane is intact.

51
Q

Fenestrated capillaries

A

Have small pores in-between endothelial cells to allow for the exchange of nutrients.

52
Q

Discontinuous capillaries

A

aka sinusoids

Have many large gaps in between the endothelium and basement membrane. These are the leakiest capillaries, found in the spleen, liver, and bone marrow.

53
Q

Skeletal muscular pump

A
54
Q

Starling forces

A

Physical forces that govern the movement of fluids (and proteins) into and out of capillaries. Consist of two filtration forces (the direction of which is from capillary to interstitium) and two reabsorption forces (the direction of which is from interstitium to capillary).

The filtration forces are capillary hydrostatic pressure and interstitial oncotic pressure. The reabsorption forces are capillary oncotic pressure and interstitial hydrostatic pressure.

55
Q

The principal Starling force of filtration is ___.

The principal Starling force of reabsorption is ___.

A

The principal Starling force of filtration is capillary hydrostatic pressure.

The principal Starling force of reabsorption is capillary oncotic pressure. (most of which comes from albumin)

56
Q

Groups of vasoactive factors

A
57
Q

Autoregulation

A

A result of myogenic and metabolic regulation of vasodilation. If perfusion pressure either falls or rises acutely over a range of perfusion pressures in a given organ’s vascular supply, these factors will control vessel diameter and buffer the change to keep flow relatively constant for a period of time.

The range of autoregulation is between approximately 60 to 170 mmHg.

58
Q

Myogenic regulation

A

Intrinsic property of vascular smooth muscle. In response to stretch pressure, they contract, vasoconstricting the vessel and increasing resistance. This prevents a surge of bloodflow from damaging the delicate capillaries behind the arterioles.

59
Q

Metabolic regulation

A

Vasodilation caused by release of metabolites by local tissue (adenosine, lactic acid, potassium, etc.) Metabolites of excercising muscle have similar effects.

60
Q

Endothelial regulation

A

Endothelial factors may act on smooth muscle to regulate tone, such as endothelin (a vasoconstrictor), NO and prostacyclin (vasodilators), etc.

61
Q

Coronary bloodflow

A

Heavily autoregulated, so perfusion stays roughly constant independent of heart activity. This is in part through shear stress activating iNOS in endothelium and NO-mediated vasodilation, and also through myogenic and metabolic pathways.

Unique to coronary flow, it is linked to the cardiac cycle: During systolic contraction flow is decreased and outflow is increased, and the opposite during diastole.

62
Q

The ___ cells in the heart are the poorest perfused, and most affected by the systolic/diastolic tide of the coronary arteries.

A

The subendocardial cells in the heart are the poorest perfused, and most affected by the systolic/diastolic tide of the coronary arteries.

63
Q

The arteriovenous pressure drop in the pulmonary circulation is ~___, while it is ~___ in the systemic circulation.

A

The arteriovenous pressure drop in the pulmonary circulation is ~10 mmHg, while it is ~90 mmHg in the systemic circulation.

64
Q

The greatest location of resistance in the circulatory system (greatest contributor to the drop in pressure from left ventricle to the right atrium) is found in:

A

The medium size arteries

likely a combination of their branching patters (transitional turbulence) and size, as well as the fact that some are in series rather than in parallel.

65
Q

Marginal turbulence is most common at. . .

A

. . . vessel bifurcations.

66
Q

The highest airway resistance is at approximately . . .

A

. . . the 6th branching point of the main bronchi.

67
Q

Air coming out of the lung on exhalation is naturally more turbulent than going in on inspiration because. . .

A

. . . the compression by the diaphragm also affects the volume of the airways. This effect is reduced the more slowly you breathe out.

68
Q

A plaque or stenosis in the renal arteries will result in . . .

A

. . . a large blood pressure barrier to glomerular filtration.

HMS Homeostasis I (62 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions