MAPIISG1 - Circulation Flashcards by Henry Scholz

Q

What are the 4 purposes of circulation?

A

Transport

Nutrients and O2 to Tissues
Waste and CO2 away from Tissues
Hormones from one area of body to another
Heat throughout the body

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What is the primary driver of circulation?

A

primarily influenced by tissue needs

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What are the primary control mechanisms of circulation

A

vasodialiation and vasoconstriction

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What effect does local tissue flow have on arterial pressure? Cardiac output?

A

arterial pressure is generally controlled independently of these

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

What are key factors of principles affecting the flow of liquids through vessels (fluid dynamics? (4)

A

Blood Flow
Pressure
Resistance
Control mechanisms mediating these characteristics

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

exchange site for nutrients, waste, electrolytes, fluid, etc

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

c. Capillaries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

collect blood from capillaries

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

d. Venules

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

transport blood from tissues to heart

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

e. Veins

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

strong vascular walls

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

a. Arteries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

blood flow is rapid

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

a. Arteries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Final small branch of arteriole system

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

b. Arterioles

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Low pressure, thin walled

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

e. Veins

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Major function: serve as blood reservoir (64% of total blood volume)

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

e. Veins

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

gradually merge into larger veins

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

d. Venules

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

walls - VERY thin (unicellular layer of endothial cells)

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

c. Capillaries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Act as control conduits - blood released into capillaries

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

b. Arterioles

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Innervated by SNS only

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

b. Arterioles

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

muscular enough to can constrict/dialate

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

e. Veins

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

contain small capillary pores

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

c. Capillaries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Strong muscular walls that vasoconstrict/dialate

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

b. Arterioles

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Permeable to small molecular substances, H2O

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

c. Capillaries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Transport blood under high pressure

a. Arteries
b. Arterioles
c. Capillaries
d. Venules
e. Veins

A

a. Arteries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Holds 64% of blood

a. Arteries
b. Capillaries
c. Veins
d. Total Pulmonary
e. Total Heart

A

c. Veins

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Q

Holds 15% of blood

a. Arteries
b. Capillaries
c. Veins
d. Total Pulmonary
e. Total Heart

A

a. Arteries

How well did you know this?

1

Not at all

2

3

4

5

Perfectly

Holds 5% of blood a. Arteries b. Capillaries c. Veins d. Total Pulmonary e. Total Heart

b. Capillaries

Holds 7% of blood a. Arteries b. Capillaries c. Veins d. Total Pulmonary e. Total Heart

e. Total Heart

Holds 9% of blood

d. Total Pulmonary

Define blood flow

the volume of blood flowing through a vessel, an organ, or the entire circulation in a given period (ml/min)

Define blood pressure

the force per unit area exerted on a vessel wall by the contained blood (mmHg)

Define resistance

opposition to flow; amount of friction blood meets when passes through the vessels

Blood Flow is affected by what 2 factors?

1. Pressure Gradient | 2. Vascular Resistance

What does Ohm's Law tell us?

Calculation of blood flow through a vessel

In Ohm's Law F=delta P / R what is delta P?

change in blood pressure between 2 ends of vessel

In Ohm's Law F=delta P / R what is R?

Resistance

What is normal adult overall blood flow?

~5,000 ml/min = cardiac output

What are the two descriptors of blood flow?

Laminar and Turbulant

Describe Laminar Flow

streamline: velocity of flow in center is > outer edges = parabolic profile

Describe Turbulent Flow

blood flows crosswise in vessel forming whorls or eddy currents

In Poiseuille's Law F = (pie deltaP r^4) / 8nl what is deltaP?

Pressure difference

In Poiseuille's Law F = (pie deltaP r^4) / 8nl what is r^4

Radius ^4

In Poiseuille's Law F = (pie deltaP r^4) / 8nl what is n?

viscosity

In Poiseuille's Law F = (pie deltaP r^4) / 8nl what is l?

length

What does Poissuilles' Law tell us?

measure of blood flow through a vessel for a given pressure difference

What is the reciprocal of resistance?

Conductance

Poissuile's Law tells us that a small change in vessel diameter causes ___

enormous change in conductance

Why does Poissuile's Law tells us that a small change in vessel diameter causes an enormous change in conductance?

Conductance of a vessel increase in proportion to the 4th power of diameter.

What plays the greatest role in resistance to flow for systemic circulation?

2/3 of resistance to flow is arteriole resistance

What influence can strong muscular walls of arterioles have on diameter?

can change diameter up to fourfold

What influence can strong muscular walls of arterioles have on blood flow?

fourfold increase in diameter can increase blood flow up to 256-fold

Viscosity has an inverse relationship to ___

blood flow

What is hematocrit?

% of blood that consists of cells

What is average Hematocrit?

40

Do men or women have a higher hematocrit?

men ~ 42 women ~ 38

Why is Polycythemia?

elevated hematocrit

What is the Theory of Circulatory Function?

NEEDS OF TISSUE tightly controls blood flow; small tissue-specific vessels dilate or constrict locally to control flow in addition to change in cardiac output (cardiac output primarily controlled by sum of all local tissues. in general, arterial pressure is controlled independently of local blood flow or cardiac output)

What is Mean Arterial Pressure (MAP)?

Pressure that propels blood to tissues

What is the equation for Mean Arterial Pressure?

MAP = DP + 1/3(PP)

What is the equation for pulse pressure?

SP - DP

What happens to MAP with increasing distance from the heart? PP?

Both MAP and PP decrease

What is the equation for Mean Pressure?

Mean Pressure = (SP + DP) / 2

What is Mean Pressure at the Vena Cavae?

~0mmHg

What is the Mean Pressure at Capillaries?

~17mmHg

What is the Mean Pressure in Pulmonary Circulation

~16mmHg

What effect does pressure have on blood flow?

increases force on blood flowing through vessels

What are the effects of vessel distension?

veins > arteries --> provide resevoir function for storing large quantities of extra blood

Compliance = ____

Capacitance

Compliance = Capacitance = total ___

total quantity of blood that can be stored in a given portion of the circulation for each mmHg pressure rise

Central Venous Pressure = ___

Right atrial pressure ~0mmHg

What 5 places serve as blood reservoirs?

1. Veins 2. Spleen 3. Liver 4. Heart 5. Lungs

What are the two phases of local blood control?

1. Acute | 2. Long Term

Describe the Acute Phase of local blood control

Fast adjustment of arterioles, metarterioles, and precapillary sphincters (i.e. small vessels)

Describe Long-Term Phase of local blood control

Adjustment over days/weeks/months to control blood flow to tissue

What are the 2 Theoretical Perspectives of local blood flow regulation?

1. Vasodilator Theory | 2. O2 Lack Theory

Describe the Vasodialator Theory

Vasodialor substance released form local tissue

What are 6 substances that vasodialiate?

1. Adenosine 2. CO2 3. Adenosine Phosphate Compounds 4. Histamine 5. Potassium Ions 6. H+

Describe the O2 Lack Theory

absence of O2, and maybe other substances, casue precapillary and metarteriole sphincters to relax and dialate

Describe dialating "upstream" arteries

Larger arteries "upstream" from local tissue control respond to effects of "downstream regulation" -Drag on "upstream" endothelium of vessel walls by rapid increased flow allows release of substance that can vasodialate the "upstream" vessels

What is released do vasodilate upstream vessels in response to an increase in blood flow?

Endothelium-derived relaxing factor (EDRF) made primarily of nitric oxide (NO)

What is Reactive Hyperemia?

is the transient increase in organ blood flow that occurs following a brief period of ischemia

What is Active Hyperemia?

is the increase in organ blood flow (hyperemia) that is associated with increased metabolic activity of an organ or tissue (exercise and skeletal muscle)

Define autoregulation of blood flow

after increase in blood flow to a tissue due to increase in arterial pressure, blood flow returns to near normal levels

What are the two theories of autoregulation of blood?

1. Metabolic | 2. Myogenic

Metabolic and myogenic?

dunno

Humoral Control | 4 Vasocontrictors

1. Norepinephrine/Epinephrine 2. Angiotension II 3. Vasopressin 4. Endothelin

Humoral Control | 2 Vasodilators

1. Bradykinin | 2. Histamine