Exam 2 – Cardio Ch 14 Flashcards by Anika Eidson

What are the major functions of the circulatory system?

Transporting nutrients to tissues
Transporting waste products away from the tissues
Transporting hormones
To maintain an appropriate environment in all tissue fluids of body for survival and optimal function of the cells

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What are the components of the circulatory system?

Pulmonary circulation
Superior vena cava 
Inferior vena cava
Veins, venules, and venous sinuses 
Aorta 
Heart 
Arteries 
Arterioles and capillaries

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What percentage of circulatory system is the pulmonary circulation?

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What percentage of circulatory system is the veins, venules, and venous system?

64%

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What percentage of circulatory system is the heart?

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What percentage of circulatory system is the arteries?

13%

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What percentage of circulatory system is the arterioles and capillaries?

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What is the rate of blood flow through many tissues controlled by?

Mainly controlled in response to a tissue’s need for nutrients

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What is the blood flow rate in a circuit?

5 L/min

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What are the two main parts of the circulatory system?

Pulmonary circulation

Systemic circulation

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Why are heart and blood vessels controlled?

To provide necessary cardiac output and arterial pressure to cause needed tissue blood flow

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What is the function of the aorta and large arteries?

Transports blood to tissues under high pressure (100mmHg)

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What type of walls do arteries have?

Strong and vascular

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What type of velocity does blood flow at in the arteries?

High velocity

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What is the function of arterioles?

Control site for blood flow

Major resistance site of circulation

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What do arterioles control?

Conduits through which blood is released into capillaries

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What type of walls do arterioles have and why?

Strong muscular walls that close arterioles completely or can, by relaxing, dilate vessels sevenfold thus having the capability of vastly altering blood flow in each tissue in response to its needs

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What is the function of the capillaries?

Major site of water and solute exchange between blood and tissue
Exchange fluid, nutrients, electrolytes, hormones, and other substances between blood and interstitial fluid

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What type of walls do capillaries have and why?

Thin walls and have numerous minute capillary pores permeable to water and other small molecules

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What is the function of large veins and venules?

Returns blood to heart under low pressure

Serves as a reservoir of blood

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What is the specific function of venules?

Collect blood from capillaries and gradually coalesce intro progressively larger veins

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What is the specific function of veins?

Conduits for transport of blood from venules back to heart
Major reservoir of extra blood
Because of low pressure, venous walls are thin
muscular enough to contract or expand

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Why is the musculature of veins important?

Serve as controllable reservoir for extra blood depending on needs of circulation

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What is the function of the pulmonary circulation?

Site of oxygen and carbon dioxide exchange

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Which component of the circulation has the largest total cross-sectional area?

Capillaries | 2500cm

What does the cross-sectional area help determine?

The rate at which blood flows through it

Which component of circulation has the smallest total cross-sectional area?

2.5cm

Which component of circulation has the greatest velocity of blood flow?

Aorta

What is velocity of blood flow?

Speed at which blood flows in the circulation (mm/sec)

What is the equation for calculating velocity of blood flow?

Velocity of blood flow = blood flow/cross sectional area

Which component of circulation has the smallest velocity of blood flow?

Capillaries

List the order of velocity of blood flow

Aorta > arterioles > small veins > capillaries

Which component of circulation is the majority of blood volume located in?

Veins, venules, and venous system

How much is the total blood volume in humans?

About 5 L

Look at blood pressure profile in circulatory system chart

What type of pressure is in the arterial tree?

High

What type of pressure is in the venous side of circulation?

Low

Where does the large pressure drop occur at?

Across the arteriolar-capillary junction

How can arterioles control blood flow?

Sphincters present can control how much blood goes through them

What are the components of the basic theory of circulatory function?

Blood flow Cardiac output Arterial pressure

How is blood flow to tissues controlled?

In relation to tissue needs

What do active tissues need in relation to blood flow?

Active tissues need more supply of nutrients which results in increased blood flow to that area

What is cardiac output controlled by?

Local tissue flow

What is cardiac output the sum of?

All local tissue flows

What is arterial pressure controlled by?

Independent of either local blood flow control or cardiac output control

Define blood flow

The quantity of blood that passes a given point in circulation in a given period of time

What two factors determines blood flow through a blood vessel?

1. Pressure difference of blood between two ends of vessel (pressure gradient), which pushes blood through vessel 2. Impediment of blood flow through vessels (vascular resistance)

What is a unit of blood flow usually expressed as?

mL or L per minute

What is the overall flow in circulation of an adult and what is it called?

5 L/min | Cardiac output

Look at dramatic variations in tissue blood flow in human body chart

What are the major determinants of blood flow?

Flow Pressure difference Resistance

What is the blood flow equation?

Q = P1-P2/R

What is flow (Q) through a blood vessel determine by?

The pressure difference (P1-P2) through the two ends of a vessel Resistance (R) of vessel

What are the characteristics of blood flow in a vessel?

Blood usually flows in streamlines with each layer of Blood remaining the same distance from the wall this type of flow is called laminar flow

What is laminar flow?

When laminar flow occurs, the velocity of the blood in the center of the vessel is greater than that toward the outer edge creating a parabolic profile

What is turbulent flow?

Blood flowing in all directions in the vessel and continually mixing within the vessel

What are the causes of turbulent blood flow?

``` High velocities Sharp turns in the circulation Rough surfaces in circulation Rapid narrowing of blood vessels Passes by an obstruction in a vessel ```

Does laminar flow make sounds?

No it is silent

Does turbulent flow make sounds?

Yes it tends to cause murmurs

Why are murmurs or bruits important?

Diagnosing vessel stenosis, vessel shunts, and cardiac valvular lesions

What does turbulent flow do to wall stress?

Increases it

What is blood pressure?

The force exerted by blood against any unit area of vessel wall

what is blood pressure measured in?

mmHg

What does a pressure of 100mmHg mean?

The force of blood was sufficient to push a column of mercury 100mm high

what are low pressures sometimes reported as?

In units of mm of water

What does 1 mmHg equal in water?

13.6 mm of water

What is resistance?

Impediment to blood flow in a vessel

How can resistance be calculated?

By dividing the pressure difference between two points in a vessel by the vessel blood flow

Look at resistance formula

What do parallel arrangements in circulation allow?

Independent control of flow between tissues

What is resistance the summation of?

All cross areas of capillaries

What is conductance?

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

What are the units for conductance?

mL/min per mmHg

What is the formula for conductance?

Conductance = 1/resistance

What is the effect of changing vessel diameter on blood flow?

Conductance is very sensitive to change in diameter of vessel Conductance of a vessel increases in proportion to the fourth power of the radius

How do changes in hematocrit or viscosity affect blood flow?

Increased hematocrit, increases blood viscosity which increases vascular resistance

What is the main protein that contributes to blood viscosity?

Albumin

What makes blood so viscous?

It's mainly large numbers of suspended red cells in blood, each of which exerts frictional drug against adjacent cells and against wall of blood vessel

Look at viscosity slide pictures