Cardio Pathophysiology Chapter 2

Cardio Root Meaning

Heart

Vascular Root Meaning

Blood vessels

Patho Root Meaning

Disease

Physiology Definition

How a living organism functions

Cardiovascular Pathophysiology Definition

The processes that lead to disease in the heart and blood vessels

Myocardium Definition

Heart muscle tissue possessing contractile function and a higher mitochondrial density than skeletal muscle

Intercalated Cells in Myocardium

Specialized junctions that allow rapid transmission of action potentials between cardiac cells

Pericardium and Pericardial Fluid

A protective outer sac enclosing the myocardium with fluid that allows smooth friction-free contractions

Pathway of Deoxygenated Blood Flow

Superior and inferior vena cava to right atrium to tricuspid valve to right ventricle to pulmonary valve to pulmonary arteries to lungs

Pathway of Oxygenated Blood Flow

Pulmonary veins to left atrium to bicuspid valve to left ventricle to aortic valve to aorta

Cardiac Conduction Sequence

SA node to AV node to AV bundle to right and left bundle branches to Purkinje fibers

SA Node Function

The intrinsic primary pacemaker of the heart

AV Node Function

Delays the contraction impulse long enough to allow ventricular filling from the atria

Purkinje Fibers Conduction Characteristic

Possesses the fastest conduction speed in the intrinsic conduction system

Peripheral Vascular Flow Pathway

Arteries to arterioles to capillaries to venules to veins

Capillaries Primary Role

Primary site of gas nutrient and waste exchange in the peripheral circulation

Coronary Arteries Function

Vascular branch delivering blood flow specifically to the myocardium

Left Coronary Artery (LCA) Main Branches

Divides into the left circumflex artery and the left anterior descending artery

Cardiac Cycle Phase 0

Blood enters the left ventricle while the mitral valve is open and the aortic valve is closed

Cardiac Cycle Phase 1

Ventricular stimulation immediately preceding ventricular contraction

Cardiac Cycle Phase 2 (Isovolumic Contraction)

All valves remain closed while ventricular pressure rapidly spikes without a change in chamber volume

Cardiac Cycle Phase 3 (Rapid Ejection)

Ventricular pressure exceeds aortic pressure opening the aortic valve and rapidly pumping blood into the aorta

Cardiac Cycle Phase 4 (Reduced Ejection)

Ventricles begin relaxing until ventricular pressure drops below aortic pressure causing the aortic valve to close

Cardiac Cycle Phase 5 (Isovolumic Relaxation)

Ventricles relax with valves closed while atria continuously fill with incoming blood

Cardiac Cycle Phase 6

Rising atrial pressure exceeds ventricular pressure allowing passive refilling of the left ventricle

Cardiac Output (Q) Definition and Formula

Total volume of blood ejected by the left ventricle per minute calculated as heart rate multiplied by stroke volume

Fick Equation for Oxygen Uptake

VO2 equals cardiac output multiplied by the arterial-venous oxygen difference

Arterial-Venous Oxygen Difference (a-vO2diff)

The quantity of oxygen extracted and consumed by working tissues from the arterial bloodstream

Chronotropic Factors

Any neural chemical or hormonal factor that directly influences heart rate

Autonomic Heart Rate Regulation

Norepinephrine and epinephrine increase heart rate while parasympathetic vagal stimulation decreases it

Stroke Volume (SV) Definition and Formula

Volume of blood ejected per contraction calculated as End Diastolic Volume minus End Systolic Volume

Inotropic Factors

Any factor that influences stroke volume and myocardial contractility vigor

Preload vs Afterload

Preload is left ventricular filling pressure at end-diastole while afterload is the aortic pressure opposing ejection

Ejection Fraction Definition and Formula

Percentage of blood pumped out of the ventricle calculated as Stroke Volume divided by End Diastolic Volume times 100

Frank-Starling Mechanism

Increased venous return stretches ventricular walls inducing a more forceful contraction and elevated stroke volume

Basal Myocardial Oxygen Consumption

The myocardium extracts nearly all available arterial oxygen at rest requiring coronary flow rate increases during exercise

Rate Pressure Product (Double Product) Formula

Calculated as heart rate multiplied by systolic blood pressure to index myocardial oxygen demand

Hemodynamic Flow Equation

Blood flow equals the pressure gradient divided by vascular resistance

Vasoconstriction vs Vasodilation

Vasoconstriction narrows vessel diameter reducing flow whereas vasodilation widens vessel diameter increasing flow

Systolic vs Diastolic Blood Pressure

Systolic is arterial pressure during ventricular contraction while diastolic is arterial pressure between beats

VO2max Definition

Criterion whole-body measure of cardiorespiratory fitness determined by cardiac output and oxygen extraction

Stroke Volume Plateau During Exercise

Stroke volume increases up to approximately 60% VO2max with subsequent cardiac output gains driven by heart rate

Acute Blood Pressure Response to Exercise

Systolic blood pressure increases substantially while diastolic blood pressure remains relatively unchanged

Response to Injury Theory of Atherosclerosis

Endothelial damage triggers platelet adhesion growth factor release smooth muscle proliferation and lipid accumulation

Causes of Endothelial Vessel Injury

Elevated LDL cholesterol hypertension smoking hyperinsulinemia circulating homocysteine and infections

Foam Cells Formation

Monocytes become activated macrophages that ingest oxidized LDL particles and transform into lipid-laden foam cells

Mechanism of Myocardial Infarction

Atherosclerotic plaque rupture stimulates localized thrombus formation occluding the lumen and precipitating cellular death

Myocardial Ischemia vs Infarction

Ischemia is inadequate oxygen delivery forcing anaerobic metabolism while infarction is irreversible cellular death