Cardiovascular System: The Heart

Front 1

Striated appearance of cardiac muscle due to

Back 1

arrangement of actin and myosin filaments

Front 2

Cardiac muscle contians___quantities of smooth sarcoplasmic reticulum

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Smaller quantities(than skeletal muscle)

Front 3

T tubules account for

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slow onset of contraction and prolonged contraction phase

Front 4

Branching muscle fibers help

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help heart to contract as a unit

Front 5

Work of heart muscle directly related to

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oxygen levels

Front 6

Energy for contraction provided by___; availability dependent on___

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ATP

Oxygen availability

Front 7

cardiac muscle cells have numerous

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mitochondria that perform oxidative metabolism at a rapid rate

Front 8

cardiac muscle has an extensive

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capillary network to provide adequate blood supply

Front 9

Cardiac muscle cells are arranged in

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spiral bundles or sheet

Front 10

Cardiac muscle cells are bound together by

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intercalated cells with gap junctions to allow rapid conduction

Front 11

intercalated disks with gap junctions also known as

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functional syncthium

Front 12

Cardiac cycle refers to

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Repetitive pumping process of two separate pumps

Front 13

One cardiac cycle goes from

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beginning of onset of one cardiac contraction to the beginning of another

Front 14

Cardiac cycle dependent on(2)

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Ability to contract
Functional integrity of conducting system

Front 15

At the beginning of ventricular diastole,

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Ventricular pressure falls below that of the atria

Front 16

Almost all ventricular filling occurs during

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first third of ventricular diastole

Front 17

Atrial systole occurs

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2/3 through ventricular diastole to complete filling

Front 18

Atria function primarily as

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reservoirs during most conditions

Front 19

Pumping of atria important during

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exercise

Front 20

3 atrial pressure waves

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A wave
C wave
V wave

Front 21

A wave

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atrial contraction

Front 22

C wave

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bulging of a-v valves @ begining of ventricular systole

Front 23

V wave

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due to continuous flow of blood into atria at end of ventricular systole

Front 24

Ventricular Contraction produces

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rapid increase in ventricular pressure, closing the AV valves

Front 25

Pressure continues to rise during atrial contraction with no increase in volvume until

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pressure exceeds pulmonary artery or aortic pressure, then valves open

Front 26

Greater pressure is generated by

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Left Ventricle

Front 27

Ventricular volume decreases during

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ejection period

Front 28

Ventricular relaxation begins

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suddenly, at the end of systole

Front 29

Closure of valves the result of

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recoil of elastic arterial walls

Front 30

A-V valves re=open when

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ventricular pressure drops below atrial pressure

Front 31

Isometric relaxation

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period between semilunar valve closure and A-V valve opening

Front 32

End diastolic volume

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volume of blood in ventricle at end of diastole(fullest)

Front 33

End systolic volume

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ventricular volume at end of systole

Front 34

Stroke Volume

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(end diastolic)-(end systolic)

Front 35

At rest, stroke volume is

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70 mL

Front 36

During exercise, stroke volume is

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200 mL

Front 37

Cardiac output

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total amount of blood pumped per minute, HR*SV

Front 38

At Rest, cardiac output is

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5L/min

Front 39

During exercise, CO is

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24L/min

Front 40

Cardiac Reserve

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Difference between CO at rest and max CO

Front 41

Dicrotic Notch in aortic pressure curve due to

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Closure of semilunar valve

Front 42

First heart sound corresponds to

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Closure of A-V valves

low pitched

Front 43

Second heart sound corresponds to

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Closure of aortic and pulmonary valves

high pitched

Front 44

Third heart sound corresponds to

detected more easily

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Turbulent flow in ventricles

detected more easily in thin, young people

Front 45

Systole is time between

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first and second heart sounds

Front 46

Diastole is time between

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second and first heart sounds

Front 47

Systole made up of(2)

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Period of isovolumic contraction
period of ejection

Front 48

Diastole made up of(3)

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Period of isovolumic relaxation
Passive ventricular filling
Active ventricular filling

Front 49

Intrinsic regulatory factors are

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not dependent on hormones or innervation

Front 50

Extrinsic regulatory factors are

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involve neural and hormonal control

Front 51

Intrinsic Regulation of Preload dependent on

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Extent of stretch on ventricular walls
Venous Return

Front 52

Increased preload leads to(4)

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increased contraction, greater stroke volume(Starling's Law)

stretched atria

increased heart rate

Front 53

Intrinsic regulation of Afterload based on

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pressure that contracting ventricles must overcome in aorta

Front 54

Aortic pressure must exceed

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170 mmHg

Front 55

Parasympathetic extrinsic regulation is mediated thru__, primarily affects___

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Mediated thru vagus nerve
primarily affects HR, can affect contraction

Front 56

Sympathetic extrinsic regulation mediated through___, has __influnnce than para, increases___

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mediated thru cardiac nerves
greater influence than para
inc HR and contractile force

Front 57

Increase in ___ can increase HR due to stretch of SA node

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right atrial pressure

Front 58

Decreased __ and increased__ activates chemoreceptors, leading to___

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dec pH, in CO2

leads to inc in HR and CO

Front 59

Inc in CO results in

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increased blood flow thorugh lungs, eliminating CO

Front 60

Extracellular concentration of this ion has little effect on cardiac muscle

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Sodium

Front 61

Excess ___ decreases HR and stroke volume

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excess Potassium ion

Front 62

Produces heart block

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twofold increase in potassium

Front 63

Excess potassium causes

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partial depolarization, decrease amplitude of action potential, less calcium for contraction

Front 64

Increased calcium extracellular

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increased force of contraction

decreased HR

Reduced frequency of SNS and PSN

Front 65

RMP of cardiac muscle dependent on

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low sodium and calcium permeability

high potassium permeability

Front 66

AP in cardiac muscle are ___ than those in skeletal muscle

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longer

Front 67

Depolarization Phase(2)

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Voltage-Gated Ca channels begin to open

Voltage gated Na channels open

Front 68

Plateau phase(3)

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Voltage-gated Na fast-channels close

Potassium channels close

Voltage-gated slow channels open

Front 69

Repolarization phase(3)

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Calcium slow channels close
Potassium channels open. then
Potassium channels close after repolarization

Front 70

Action potentials in cardiac cells are conducted from

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cell to cell

Front 71

Rate of action potential propogation is slower because

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cardiac cells are smaller in diameter and shorter in length

Front 72

SA node is pacemaker because

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it has the fastest rate of spontaneous generation of potentials

-less negative RMP
-large # of Ca channels

Front 73

Effects of sympathetic stimulation on SA action potential

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increase the slope(more rapid depolarization)

Beta-1 receptors

Front 74

Effects of parasympathetic stimulation on SA action potential

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decrease the slope(slower depolarization)

Muscarinic receptors

Front 75

Heirarchy of pacemakers

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SA node> AV node> AV bundle>purkinje fibers

Front 76

Ectopic pacemakers

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Tissues other than SA node that generate action potentials spontaneously

Front 77

Cardiac Conduction:

Impulse originates in

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SA node

Front 78

Cardiac Conduction:

Electrically separates atria and ventricles

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valve annulus

Front 79

Cardiac Conduction:

acts as a filter and bridge to ventricles

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AV node

Front 80

Cardiac Conduction:

Allows for propagation of impulse

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Branching of purkinje fibers

Front 81

Path of conduction

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SA node-->AV node-->AV bundle-->Purkinje fibers down to apex, left ventricle, R ventricle

Front 82

EAbsolute refractory period

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cell is completely insensistive to stimulation

Front 83

Relative refractory period

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cell exhibits reduced sensitivity

Front 84

long refractory period

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ensures relaxation is complete, prevents tetanic contractions

Front 85

ECG detects

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summation of all action potentials

Front 86

ECG cannot provide

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measurement of contraction or BP

Front 87

ECG can provide info concernin

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rate and rhythm
abnormal conduction pathways
hypertrophy/atrophy of heart

Front 88

P wave

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atrial contraction

Front 89

PR interval

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AV nodal contraction

Front 90

QRS complex

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ventricular contraction

Front 91

T wave

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repolarization of ventricles

Front 92

Changes in ST segment may indicate

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myocardial infaction

Front 93

Drug induced arrythmyia related to prolonged

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QT interval