CARDIOVASCULAR SYSTEM Flashcards
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
THE HEART
two separate pumps
Each of these is a ______, two chamber pump composed of an ______ and a ______
pulsatile, atrium, ventricle.
______
• weak primer pump for the ventricle moving blood into the ventricle
Atrium
______
• 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
______
• two-layer sac which protects the heart and holds it in place.
Pericardium
______
• succession of contractions
CARDIAC RHYTHMICITY
______
• transmit action potentials throughout the cardiac muscle to cause the heart’s rhythmical beat.
CARDIAC RHYTHMICITY
CARDIAC MUSCLE 3 major types
• atrial muscle
• ventricular muscle
• specialized excitatory and conductive muscle fibers
______ and ______ muscles contract like the skeletal muscle, except that the duration of contraction is much ______
Atrial, ventricular, longer
______ contract feebly because they contain few contractile fibrils
Specialized excitatory and conductive fibers
______
• 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
______
• Is a syncytium
CARDIAC MUSCLE
CARDIAC MUSCLE
• ______ discs are cell membranes that separate individual cardiac muscle cells from one another.
intercalated
______ are made up of many individual cells connected in series and in parallel with one another.
cardiac muscle fibers
Myocardial cell structure
Cells contain ______, ______, ______ and ______
myosin, actin, troponin, tropomyosin
Myocardial cell structure
______ are present at the intercalated disks
Entire heart behaves as an ______
Gap junctions, electrical syncytium
Myocardial cell structure
______ are more numerous in cardiac muscles than in skeletal muscles
Mitochondria
______ - invaginations in the cell membrane. Carry action potentials into the cell interior
T tubules
______ - sites of storage of Ca++ needed for excitation-contraction coupling
Sarcoplasmic reticulum
THE HEART
• Two syncytia:
Atrial syncytium
Ventricular syncytium
THE HEART
Two syncytia:
______
- walls of the two atria
Atrial syncytium
THE HEART
Two syncytia:
______
- constitutes the walls of the two ventricles
Ventricular syncytium
The atria are separated from the ventricles by ______ that surrounds the ______ (A-V) valvular openings
fibrous tissue, atrioventricular
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
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)
- Atrial systole
- Isovolumetric contraction
- Rapid ventricular ejection
- Reduced ventricular ejection
- Isovolumic (Isometric) Relaxation
- Rapid ventricular filling
- 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 ______
5L
______
• 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
