Ch 42 Review Of Hemodynamics

Front 1

The circulatory system has two primary functions:

Back 1

(1) delivery of oxygen, nutrients, hormones, electrolytes, and other essentials to cells; and
2) removal of carbon dioxide, metabolic wastes, and other detritus from cells.

Front 2

The circulatory system, It has two major divisions: the pulmonary circulation and the systemic circulation.What is each's function?

Back 2

The pulmonary circulation delivers blood to the lungs. The systemic circulation delivers blood to all other tissues.

Front 3

_______ are the sites for exchange of fluid, oxygen, carbon dioxide, nutrients, hormones, wastes, and so forth.

Back 3

Capillaries

Front 4

Cardiac output =

Back 4

the product of heart rate times stroke volume

Front 5

Cardiac preload can be expressed as either end-diastolic volume or ________ _______

Back 5

end-diastolic pressure

Front 6

Stroke volume is determined by ...

Back 6

1)myocardial contractility,
2)cardiac preload,
3)and cardiac afterload.

Front 7

Preload is defined as the amount of tension (stretch) applied to a muscle before contraction.
How is it determined?

Back 7

the amount of tension (stretch) applied to a muscle before contraction.
In the heart, preload is determined by the force of venous return.

Front 8

Afterload is defined as

Back 8

the load against which a muscle exerts its force.

For the heart, afterload is the AP that the left ventricle must overcome to eject blood.

Front 9

Cardiac afterload is determined primarily by_____ ______, which in turn is determined by the degree of constriction in arterioles.

Back 9

peripheral resistance

Front 10

What does Starling's Law describe?

Back 10

the force of ventricular contraction is proportional to myocardial fiber length. Because of this relationship, when more blood enters the heart, more is pumped out. As a result, the healthy heart is able to precisely match output with venous return. In a failing heart, Starling’s Law breaks down.

The force of contraction no longer increases in proportion to increased ventricular filling. (The rubberband loses its elasticity)

Blood backs up behind the failing ventricle, which causes blood to back up in the pulmonary circulation. This leads to respiratory symptoms, including dyspnea, or shortness of breath.

Front 11

With regard to pharmacology, the most important factor is ______ ____ ______ (ie, the force that returns blood to the heart).

Back 11

systemic filling pressure

Front 12

The ANS regulates AP through

Back 12

(1) tonic control of heart rate and peripheral resistance and (2) the baroreceptor reflex.

Front 13

The baroreceptor reflex is only useful for ____-_____ control of AP.

Back 13

short-term

Front 14

How does the baroreceptor reflex follow out?

Back 14

Baroreceptors in the aortic arch and carotid sinus sense AP and relay this information to the vasoconstrictor center of the medulla. When AP changes, the vasoconstrictor center compensates by sending appropriate instructions to arterioles, veins, and the heart.

Front 15

Provide an example of how the baroreceptor reflex changes the shape size of vessels to control AP when AP drops ?

Back 15

the vasoconstrictor center causes (1) constriction of nearly all arterioles, thereby increasing peripheral resistance; (2) constriction of veins, thereby increasing venous return; and (3) acceleration of heart rate (by increasing sympathetic impulses to the heart and decreasing parasympathetic impulses).

Front 16

How do the kidney's provide long term control of BP if AP is too low for a long time?

Back 16

by regulating blood volume.

When the arterial pressure remains low for a long period, the kidneys respond by retaining water and sodium.

Front 17

When a patient has decreased cardiac output what is the baroreceptor response?

Back 17

to increase volume by the reuptake of water to continue to perfuse the body and the kidneys. This is evidenced by tubular reabsorption.

Front 18

When a patient is experience postural hypotension what is occuring?

Back 18

• Postural (orthostatic) hypotension is caused by decreased venous return secondary to pooling of blood in veins, which can occur when we assume an erect posture. When a patient stands, blood pressure decreases due to the reduced venous return to the heart. There will therefore be a compensatory increase in heart rate, likely to be noted as tachycardia.

Front 19

How is that venodilators can cause tachycardia?

Back 19

Venous dilators can decrease the rate and volume of blood fllowing back to the heart and can lead to postural hypotension.

Front 20

What role do Natriuretic peptides play in the circulatory system?

Back 20

Natriuretic peptides defend the cardiovascular system from volume overload—primarily by reducing blood volume and promoting vasodilation.