CARDIOVASCULAR SYSTEM Flashcards by Secret acc

THE HEART

two separate pumps:
• ______ that pumps blood through the lungs
• ______ that pumps blood through the systemic circulation that provides blood flow to the other organs and fissues of the body

right heart, left heart

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THE HEART

two separate pumps

Each of these is a ______, two chamber pump composed of an ______ and a ______

pulsatile, atrium, ventricle.

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______
• weak primer pump for the ventricle moving blood into the ventricle

Atrium

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______
• supply the main pumping force that propels the blood either
• (1) through the ______ by the right ventricle
• (2) through the ______ by the left ventricle

Ventricles, pulmonary circulation, systemic circulation

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______
• two-layer sac which protects the heart and holds it in place.

Pericardium

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______
• succession of contractions

CARDIAC RHYTHMICITY

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______
• transmit action potentials throughout the cardiac muscle to cause the heart’s rhythmical beat.

CARDIAC RHYTHMICITY

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CARDIAC MUSCLE 3 major types

• atrial muscle
• ventricular muscle
• specialized excitatory and conductive muscle fibers

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______ and ______ muscles contract like the skeletal muscle, except that the duration of contraction is much ______

Atrial, ventricular, longer

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______ contract feebly because they contain few contractile fibrils

Specialized excitatory and conductive fibers

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______
• exhibit automatic rhythmical electrical discharge in the form of action potentials or conduction of the action potentials providing an excitatory system that controls the rhythmical beating of the heart.

Specialized excitatory and conductive fibers

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______
• Is a syncytium

CARDIAC MUSCLE

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CARDIAC MUSCLE
• ______ discs are cell membranes that separate individual cardiac muscle cells from one another.

intercalated

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______ are made up of many individual cells connected in series and in parallel with one another.

cardiac muscle fibers

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Myocardial cell structure

Cells contain ______, ______, ______ and ______

myosin, actin, troponin, tropomyosin

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Myocardial cell structure

______ are present at the intercalated disks
Entire heart behaves as an ______

Gap junctions, electrical syncytium

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Myocardial cell structure

______ are more numerous in cardiac muscles than in skeletal muscles

Mitochondria

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______ - invaginations in the cell membrane. Carry action potentials into the cell interior

T tubules

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______ - sites of storage of Ca++ needed for excitation-contraction coupling

Sarcoplasmic reticulum

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THE HEART

• Two syncytia:

Atrial syncytium
Ventricular syncytium

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THE HEART

Two syncytia:
______
- walls of the two atria

Atrial syncytium

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THE HEART

Two syncytia:
______
- constitutes the walls of the two ventricles

Ventricular syncytium

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The atria are separated from the ventricles by ______ that surrounds the ______ (A-V) valvular openings

fibrous tissue, atrioventricular

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THE HEART

Potentials are conducted by way of a specialized conductive system called the ______, a bundle of conductive fibers several millimeters in diameter

A-V bundle

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THE HEART The division of the muscle of the heart into two functional syncytia allows the atria to ______ a short time ahead of ventricular contraction, which is important for ______

contract, heart pumping

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL

Phase 0 (Depolarization) Phase 1 (Initial Repolarization) Phase 2 (Plateau) Phase 3 (Rapid Repolarization) Phase 4 (Resting Membrane Potential)

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • fast Na Channels open When the cardiac cell is stimulated and depolarizes, the membrane potential becomes more positive.

0, Depolarization

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • Voltage-gated sodium channels (fast sodium channels) open and permit sodium to rapidly flow into the cell and depolarize it.

0, Depolarization

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • fast Na Channels close

1, Initial Repolarization

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • the cell begins to repolarize, and potassium ions leave the cell through open potassium channels.

1, Initial Repolarization

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • Calcium Channels open and fast potassium channels close. A brief initial repolarization occurs and then plateaus. The voltage-gated calcium ion channels open slowly during phases 1 and 0, and calcium enters the cell while potassium channels close

2, Plateau

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • decreased potassium ion efflux and increased calcium ion influx causes the action potential to plateau.

2, Plateau

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • Calcium channels close and slow K Channels open

3, Rapid Repolarization

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • The closure of calcium ion channels and increased potassium ion permeability, permitting potassium ions tonexit the cell rapidly, ends the plateau and returns the cell membrane potential to its resting level.

3, Rapid Repolarization

PHASES OF CARDIAC MUSCLE ACTION POTENTIAL Phase ______ (______) • averages about-80 to -90 millivolts.

4, Resting Membrane Potential

Cardiac action potentials:

Conduction velocity Refractory period

Cardiac action potentials Conduction velocity • Fastest in the ______

Purkinje system

Cardiac action potentials Conduction velocity • Slowest in the ______

AV node

action potentials Refractory period • ______ - No action potential could be initiated

Absolute refractory period (ARP)

Cardiac action potentials Refractory period • ______ - more than the usual inward current is required to initiate an action potential

Relative refractory period (RRP)

______ - cardiac events that occur from the beginning of one heartbeat to the beginning of the next

Cardiac Cycle

Cardiac Cycle - The ______ is used in general as an event marker

ECG

Cardiac Cycle • Generation of an action polential in the ______ (near the opening of the superior vena cava)

sinus node

Cardiac Cycle • The action potential travels rapidly through both ______ and the ______ into the ______

atria, A-V bundle, ventricles

Cardiac Cycle • There is a delay of more than ______ second during passage of the cardiac impulse from the atria into the ventricles which allows the atria to contract ahead of ______

0.1, ventricular contraction

Cardiac Cycle • Blood flows into the ______ before the strong ventricular contraction begins

ventricles

Cardiac Cycle ______ • act as primer pump for the ventricles

Atria

Cardiac Cycle ______ • major source of power for moving blood through the body's vascular system.

Ventricles

Diastole and Systole • total duration of the cardiac cycle, including systole and diastole, is the ______ of the heart rate

reciprocal

Diastole and Systole • top three curves (pressure changes in the ______, ______, and ______)

aorta, left ventricle, left atrium

Diastole and Systole • fourth curve depicts changes in ______

left ventricular volume

Diastole and Systole • fifth depicts the ______

ECG

Diastole and Systole • sixth depicts a ______ a recording of the sounds produced by the heart as it pumps.

phonocardiogram

Electrocardiogram (ECG) ______ • Represents atrial depolarization

P wave

Electrocardiogram (ECG) ______ • Is the interval between the beginning of P wave to beginning of Q wave

PR interval

Electrocardiogram (ECG) ______ • Increases with problems in conduction velocity (heart blocks)

PR interval

Electrocardiogram (ECG) ______ • Varies with heart rate.

PR interval

Electrocardiogram (ECG) ______ • Represents ventricular depolarization

QRS complex

Electrocardiogram (ECG) ______ • From beginning of QRS to end of T wave

QT interval

Electrocardiogram (ECG) ______ • Represents entire ventricular depolarization and repolarisation

QT interval

Electrocardiogram (ECG) ______ • Is the segment from the end of S wave to the beginning of T wave

ST segment

Electrocardiogram (ECG) ______ • Is isoelectric

ST segment

Electrocardiogram (ECG) ______ • Represents the period when the ventricle is depolarized

ST segment

Electrocardiogram (ECG) ______ • Represents ventricular repolarisation

T wave

Cardiac Cycle (7)

1. Atrial systole 2. Isovolumetric contraction 3. Rapid ventricular ejection 4. Reduced ventricular ejection 5. Isovolumic (Isometric) Relaxation 6. Rapid ventricular filling 7. Reduced ventricular filling (diastasis)

Cardiac Cycle ______ - preceded by the P wave (electrical activation of atria)

Atrial systole

Cardiac Cycle ______ - contributes to ventricle filling

Atrial systole

Cardiac Cycle ______ - the moderately increased pressures that have developed in the atria push the A-V valves open and allow blood to flow rapidly into the ventricles (Period of rapid filling of the ventricles)

Atrial systole

Cardiac Cycle ______ - When ventricle pressure exceeds that of the atria, AV valves close producing the 1st heart sound.

Isovolumetric contraction

Cardiac Cycle ______ - Ventricular pressure increases isovolumetrically while all four valves are closed

Isovolumetric contraction

Cardiac Cycle ______ - When ventricle pressure exceeds aortic pressure, aortic valve open

Rapid ventricular ejection

Cardiac Cycle ______ - Rapid ejection of blood to aorta

Rapid ventricular ejection

Cardiac Cycle ______ - Most of the stroke volume is ejected during this phase

Rapid ventricular ejection

Cardiac Cycle ______ - Atrial filling begins and the ventricles start repolarising

Rapid ventricular ejection

Cardiac Cycle ______ - Blood continues to be ejected slowly

Reduced ventricular ejection

Cardiac Cycle ______ - Both ventricular and aortic pressure starts dropping

Reduced ventricular ejection

Cardiac Cycle ______ - Atrial filling continues

Reduced ventricular ejection

Cardiac Cycle ______ - Repolarisation of the ventricle is now complete.

Isovolumic (Isometric) Relaxation

Cardiac Cycle ______ - Semilunar valves close and the 2nd heart sound occur

Isovolumic (Isometric) Relaxation

Cardiac Cycle ______ - All 4 valves are closed while the ventricle relaxes - causing a rapid drop in pressure

Isovolumic (Isometric) Relaxation

Cardiac Cycle ______ - Mitral valve open and ventricle fill from the atria rapidly

Rapid ventricular filling

Cardiac Cycle ______ - Longest phase of the cardiac cycle

Reduced ventricular filling (diastasis)

Cardiac Cycle ______ - Ventricle fill at a slower rate. The time for this varies with the heart rate

Reduced ventricular filling (diastasis)

______ • degree of muscle tension when it begins to contract

Preload

______ • the end-diastolic pressure when the ventricle has become filled

Preload

______ • the load against which the muscle exerts its contractile force

Afterload

______ • the pressure in the aorta leading from the ventricle

Afterload

The importance of the concepts of preload and afterload is that in many abnormal functional states of the heart or circulation, the preload or the afterload, or both are altered from ______ to a ______.

normal, severe degree

______ • Is the volume of blood ejected from each ventricle per minute

Cardiac Output

Cardiac Output • Expressed by the following: CO = ______

Stroke Volume x HR

Cardiac output of a 70 kg man is about ______

______ • Is the volume of blood ejected from each ventricle on each beat

Stroke volume

Stroke volume • Expressed by the following: Stroke volume = ______

EDV - ESV

Stroke volume • Normally is about ______ (as EDV = ______ & ESV = ______)

70 ml, 140 ml, 70 ml

Stroke volume • SV = (______)

~2 x pulse pressure

Cardiac Index • Expressed by the following: cardiac index = ______

CO / body surface area

______ • Gives a correct estimation of the cardiac output depending on the size of the person

Cardiac Index

______ • Is the fraction of end-diastolic volume ejected in each stroke volume

Ejection fraction

Ejection fraction • Is normally ______ or ______%

0.55, 55

Ejection fraction • Is expressed by the following equation: Ejection fraction = ______

SV End-diastolic volume

______ • Is the work the heart performs on each beat

Stroke work

Stroke work • Stroke work = ______

Aortic pressure x Stroke volume

______ are the primary energy source for stroke work

Fatty acids

______ • Is directly related to the amount of tension developed by the ventricles

Myocardial oxygen consumption

Myocardial oxygen consumption It is increased by: 1. increased ______ (______) 2. Increased ______ (______) 3. Increased ______ 4. Increased ______

afterload, aortic pressure size of the heart, Laplace's law contractility heart rate

4 factors determine cardiac output:

Heart Rate Pre Load Myocardial contraction After load

"The energy of cardiac contraction is depended on the resting length of the cardiac muscle fibre"

STARLING LAW OF THE HEART

______ - Explains how heart matches input (VR) to output (C.O) and how cardiac output of right and left heart are equalized to prevent congestion

"When stretch is more, contraction is more"

______ - describes the increase in stroke volume that occurs in response to an increase in venous return (or end-diastolic volume)

Frank-Starling relationship

Venous return: • 🔺P = ______

flow x Resistance

Rise of the venous Pressure leads to more ______

Venous Return

Autonomic effects on the heart & vessels • Innate rate of the SA node is about ______

100/min

Autonomic effects on the heart & vessels • Both ______ and ______ have effects on the rate

sympathetics, parasympathetics

Autonomic effects on the heart & vessels • If parasympathetics are blocked, the rate rises to ______

150-180/min

______ - producing changes in the heart rate

Chronotropic effect

______ - producing changes in conduction velocity mainly in the AV node

Dromotropic effect

______ - produce an effect on the contractility of the heart

Inotropic effect

Parasympathetic effect on heart • SA node, atria and AV node has ______

parasympathetic innervation

Parasympathetic effect on heart • Neurotransmitter is ______ acting on muscarinic receptors Effects are: • ______ (threshold potential Is reached slowly) • ______ through the AV node • ______ (decreased Inward Ca++ current)

Acetylcholine Decreasing heart rate Decrease conduction velocity Increase the PR interval

Sympathetic effect on heart • Neurotransmitter is ______. Acting on B1 receptors Effects are: • ______ (threshold potential is reached faster • ______ through the AV node • ______ (increase inward Ca++ current) • ______

Norepinephrine Positive chronotropic effect Increase conduction velocity Decrease the PR interval Positive inotropic effect

Cardiac Abnormalities ______ • occurs after coronary occlusion, and a strong current of injury flows from the infarcted area of the ventricles

Coronary Ischemia

Cardiac Abnormalities ______ • caused by thrombosis of the anterior descending branch of the left coronary artery

Anterior Wall Infarction

Cardiac Abnormalities ______ • the infarct is near the apex on the posterior wall of the left ventricle.

Posterior Wall Infarction

Cardiac Abnormalities ______ • pain from the heart felt in the pectoral regions of the chest.

Angina Pectoris

Cardiac Abnormalities ______ • radiates to the left neck area and down the left arm

Angina Pectoris

Cardiac Abnormalities ______ • typically caused by moderate ischemia of the heart

Angina Pectoris

Cardiac Abnormalities ______ • inability of the heart to pump blood into the circulation

Heart Failure

Cardiac Abnormalities ______ • Abnormalities with rate or rhythm of the heart

Cardiac Arrythmia