Physiology 2.6 :: Complete

Front 1

Heart failure is defined as the inability of the hear to pump blood FORWARD at a sufficient rate to meet the ? demands of the body or the ability to do so only if the cardiac filling pressures are abnormally high.

Back 1

Metabolic demands

Front 2

What three factors contribute to Stroke Volume?

Back 2

Contractility

Preload

Afterload

Front 3

The term used to define cardiac output per square meter of body surface area.

Back 3

Cardiac Index

(as cardiac output INCREASES approx in proportion to surface area of the body)

Front 4

What are the factors that affect HEART RATE?

Back 4

Autonomic Nervous System

Catecholamines = increase heart rate by increasing the SA node firing rate

ACh = slows heart rate by decreasing SA node firing rate

Front 5

What is Bowditch staircase / Treppe effect?

Back 5

Rate-Induced Regulation

Tachycardia increases NET INFLUX of Ca2+ into myocardial cell

=> larger SR Ca2+ content

=>> enhances CARDIAC CONTRACTILITY

Front 6

What is the term used to define the
load imposed on the cardiac myocytes AT REST just before isovolumetric contraction begins?

(at the end of diastole)

often approximated by the EDV or EDP

Back 6

Preload

(passive tension, diastolic tension)

Front 7

The mechanical energy set free in the passage from the resting to the active state is a function of the ?

the greater the stretch of teh ventricle in diastole, the greater the ?

Back 7

length of the fiber

stroke work achieved in systole

Front 8

Before the ventricle is filled with blood, are the sarcomeres at optimal length?

Back 8

No

optimal length is achieved when ventricles are filled thereby achieving better force of contraction

Front 9

Reduced sarcomere length during DIASTOLE will result in ?

Back 9

reduced systolic PRESSURE and CONTRACTILITY

Front 10

What are the possible mechanisms by which short sarcomere lengths reduces systolic pressure and contractility?

Back 10

Ca2+ affinity to Troponin C

Myofilaments Ca2+ sensitivity

entry of Extracellular Ca2+

Front 11

Overstretching of sarcomeres will lead to reduction in the development of ? during systole

Back 11

active tension

Front 12

The increase in preload will increase the ? of muscle shortening

Back 12

speed

the more we stretch ventricular muscle during diastole -- the faster it will contract during systole

(also greater pressure/force during systole)

Front 13

True or False

Increased preload will cause a increase in contractile force and stroke volume.

Back 13

True

Front 14

The term used to describe the pressure in the superior/inferior vena cava or right atrium.

Back 14

Central Venous Pressure (CVP)

Front 15

Central Venous Pressure reflects changes in ? and ?

Back 15

venous return

Central Blood Volume

Front 16

What is the equation for Venous Return?

Back 16

Q = ΔP/R

ΔP = peripheral venous compartment - Central Venous Compartment

Front 17

An increase in Venous Return will ultimately cause ?

Back 17

Increase in Cardiac Output

Front 18

Increase Venous Return will lead to => ? => ? => ? => ?

Back 18

Increase cardiac filling pressure

increase ventricular preload

increase in ventricular contractility

increase cardiac output

Front 19

What must exist between the peripheral venous compartment and Central Venous compartment before blood can flow back into the heart (venous return)?

Back 19

Pressure Gradient

Front 20

What are the conditions that affect venous return/CVP/preload?

Back 20

Hypovolemia / Hypervolemia

Gravity/Position

Muscular Activity and Venous Valves (skeletal muscle pump)

Front 21

When a patient shifts from supine to a standing position, what will most likely happen to the venous return, preload, and cardiac output?

Back 21

Decrease venous return

decrease preload

decrease cardiac output

Front 22

As ventricular filling time increases

? end-diastolic volume

=> ? preload

=> ? force during systole

Back 22

Increase EDV

Increase Preload

Increase Force during Systole

Front 23

A patient exhibiting Tachycardia will have ? ventricular filling time

=> ? EDV or Preload

Back 23

decreased Ventricular Filling time

decrease EDV or Preload

Front 24

As ventricular compliance INCRASES

a given filling pressure will produce a ? in ventricular volume

causing EDV to ?

Back 24

INCREASE ventricular volume

Increase EDV

Front 25

True or False

Compliant left ventricle can accommodate MORE volume at LOWER pressure

Back 25

True

Front 26

What factors reduce ventricular Compliance?

Back 26

Increased wall thickness

Increased collagen in cardiac muscle

Front 27

What is the term that is often approximated by Systemic Arterial Pressure because it determines the TENSION which must be developed by VENTRICULAR MUSCLE FIBERS before it can shorten/contract?

Back 27

Ventricular Afterload

(afterload is the pressure opposing ejection)

Front 28

What is the Afterload equation?

Back 28

Afterload = (Arterial Pressure x Chamber radius) / 2x wall thickness

Front 29

The Law of LaPlace describes the factors that alter Afterload. What are these factors? (2)

Back 29

afterload DIRECTLY PROPORTIONAL to arterial pressure and ventricular chamber radius

afterload INVERSELY PROPORTIONAL to 2x ventricular wall thickness

Front 30

An increase in Arterial Pressure will ? afterload

Back 30

Increase

Front 31

pathologic enlargement of ventricular chamber radius will ? afterload

Back 31

increase

Front 32

increase in wall thickness (physiologic) will ? afterload

Back 32

decrease afterload


-because force is distributed over a GREATER MASS per unit surface of ventricular muscle

Front 33

Increase in afterload will ? the velocity of cardiac shortening.

Back 33

Decrease

Front 34

An increase in afterload will ultimately lead to ? stroke volume

Back 34

decreased stroke volume

Front 35

How will an increase in afterload affect end-systolic volume?

Back 35

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Front 36

How will increases in afterload affect myocardial oxygen requirement?

Back 36

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Front 37

The term used to describe an intrinsic measure of cardiac performance/Inotropic state of the heart INDEPENDENT of preload, afterload or heart rate.

Back 37

Cardiac Contractility

Front 38

Cardiac Contractility is independent of what three things?

Back 38

Preload

Afterload

Heart rate

Front 39

True or False

Contractility is measured by ventricle's rate of pressure development or change in pressure over time.

Back 39

True

Front 40

True or False

An increase in contractility is often due to parasympathetic nervous system stimulation.

Back 40

FALSE

is often due to SYMPATHETIC nervous system stimulation

Front 41

During Sympathetic stimulation...

ventricular pressure will ? rapidly and reach a ? systolic pressure.

Back 41

increase

higher

Front 42

True or False

Increase in systolic pressure will also INCREASE in the aorta due to an increased stroke volume over a shorter period of time

Back 42

True

Front 43

If sympathetic stimulation occurs, will the ejection fraction increase or decrease?

How will this affect Diastolic volume and pressure?

Back 43

Increase ejection fraction

Decrease Diastolic volume and pressure

Front 44

Page 12 b, c, d and Page 13

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Back 44

Page 12 b, c, d and page 13

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