Pathophysiology: Alterations in Blood Pressure, Blood Flow, Cardiac Function, Heart Failure, and Shock

Comprehensive vocabulary flashcards covering vascular disorders, hemodynamic regulation, coronary artery syndromes, cardiomyopathy, pericardial diseases, heart failure, and shock states based on the pathophysiology lecture study guides.

Vascular Endothelium

A single-cell layer, versatile, multifunctional tissue that controls the movement of nutrients, gases, and water between blood and tissues, regulates vascular tone via smooth muscle action (vasodilation and vasoconstriction), and participates in coagulation balance, inflammation, immunity, and angiogenesis.

Baroreceptors

Pressure-sensitive receptors located within the walls of blood vessels and the heart that respond to changes in the stretch of the vessel wall to trigger neural compensatory adjustments in blood pressure.

Chemoreceptors

Sensory structures located in the carotid bodies that monitor arterial blood levels of oxygen, carbon dioxide, and hydrogen ions to mediate reflex changes in blood pressure and respiratory rate.

Autoregulation

The intrinsic ability of local vascular beds and tissues to dilate or constrict arterioles to match blood flow with their metabolic oxygen and nutrient demands.

Vasopressin (Antidiuretic Hormone / ADH)

A humoral regulatory hormone released from the posterior pituitary in response to decreased blood volume or decreased blood pressure that alters vascular tone to support blood pressure.

Orthostatic (Postural) Hypotension

An abnormal drop in arterial blood pressure occurring when moving from a lying to standing position due to blood pooling in the lower extremities, defined clinically as a sustained reduction within $3\,\text{minutes}$ of standing of systolic blood pressure $\ge 20\,\text{mmHg}$ or diastolic blood pressure $\ge 10\,\text{mmHg}$.

Atherosclerosis

A chronic inflammatory disease characterized by the progressive accumulation and buildup of fibro-fatty lesions inside the arterial wall, predominantly affecting medium to large arteries at areas of turbulent flow such as curvatures and bifurcations.

Stable Plaque

An atherosclerotic lesion covered by a thick fibrous cap that is less likely to rupture, resulting in gradual vessel wall hardening and luminal narrowing over time in a chronic and progressive manner.

Unstable Plaque

An atherosclerotic lesion with a thin fibrous cap that is more prone to rupture, which can trigger acute thrombus formation with sudden blockage or cause arterial walls to lose elasticity and develop aneurysms.

Arterial Aneurysm

An abnormal localized dilation of a blood vessel that dilates, weakens, and stretches the vessel wall, rendering it thinner and creating a high risk of rupture, hemorrhage, or clot formation.

Varicose Veins

Dilated and tortuous veins of the lower extremities occurring in superficial or deep-channeled systems due to valvular incompetence (loss of unidirectional flow) or deep vein thrombosis, which may progress into chronic venous insufficiency.

Intermittent Claudication

A clinical manifestation of muscle ischemia during exercise activity caused by obstruction of peripheral arterial flow that characteristically improves with rest.

Raynaud Disease

A peripheral vascular disorder characterized by intense vasospasm of the arteries supplying the fingers, typically triggered by cold exposure or emotional stress.

Peripheral Arterial Disease (PAD)

A chronic, progressive atherosclerotic disorder that leads to partial or total occlusion of the peripheral vasculature.

Arterial Vasculitis

Inflammation of the arterial walls capable of inflicting structural damage on blood vessels.

Chronic Venous Insufficiency

A pathological state occurring when leg veins and venous valves fail to maintain effective forward blood movement back to the heart, frequently developing as a progression from varicose veins.

Thrombophlebitis

Inflammation of a vein precipitated by the presence of a blood clot, most commonly involving the superficial venous system.

Venous Thromboembolism (VTE)

The development of a blood clot (thrombus) inside a deep vein that can dislodge as an embolus and migrate through circulation to the pulmonary arterial bed, occluding blood flow to the lungs.

Cardiac Output (CO)

The total volume of blood pumped by the heart per minute (normal adult range: $4\text{--}8\,\text{L/min}$), calculated mathematically by multiplying heart rate by stroke volume.

Stroke Volume (SV)

The volume of blood ejected from the ventricle with each cardiac contraction (normally approximately $60\text{--}100\,\text{mL}$), determined by preload, afterload, and contractility.

Preload

The volume of blood returning to the heart and the resulting end-diastolic stretch and filling of the ventricles prior to contraction.

Afterload

The systemic or pulmonary vascular resistance against which the ventricle must contract and generate pressure to eject blood.

Myocardial Contractility

The inherent force and vigor with which the ventricular heart muscle contracts, independent of loading conditions.

Stable Angina

A predictable pattern of cardiac chest pain that occurs with physical exertion or emotional stress and is typically relieved by rest or sublingual nitroglycerin.

Unstable Angina

Unpredictable chest discomfort occurring at rest or with minimal exertion that is unrelieved by rest; constitutes a medical emergency under acute coronary syndromes (ACS) without elevation of cardiac biomarkers (troponin).

Variant / Prinzmetal's Angina

Angina caused by coronary artery vasospasm that occurs unpredictably at rest, frequently manifesting during the night or early morning hours.

NSTEMI (Non-ST-Segment Elevation Myocardial Infarction)

A clinical acute coronary syndrome typically caused by near-complete coronary arterial occlusion, characterized by elevated cardiac biomarkers (troponin) indicating myocardial injury that does not extend completely through all three heart wall layers.

STEMI (ST-Segment Elevation Myocardial Infarction)

Myocardial necrosis resulting from prolonged ischemia and acute lack of oxygen that spans transmurally through the full thickness of the ventricular wall, presenting with positive troponin biomarkers and ST elevation on an ECG.

Pericarditis

Inflammation of the pericardial sac surrounding the heart, presenting clinically with sharp, pleuritic chest pain that worsens during inspiration or when supine, improves upon sitting up and leaning forward, and features an audible pericardial friction rub.

Pericardial Effusion

An abnormal accumulation of fluid within the pericardial cavity caused by inflammatory or infectious fluid shifting, or direct extravasation of blood from a myocardial defect.

Cardiac Tamponade

A life-threatening clinical emergency characterized by acute mechanical compression of the heart due to rapid or massive accumulation of fluid, blood, pus, or air within the pericardial sac, impairing ventricular filling.

Pericardiocentesis

A therapeutic and diagnostic procedure involving the insertion of a needle into the pericardial space to aspirate excess fluid and relieve intrapericardial pressure.

Hypertrophic Cardiomyopathy

A cardiac condition where the myocardium is abnormally thickened (especially the interventricular septum), creating stiff muscle that impairs diastolic relaxation and filling while reducing internal ventricular chamber volume.

Dilated Cardiomyopathy

A primary myocardial disorder characterized by overstretched, thin ventricular walls and dilated chambers, causing weak myocardial contractility (systolic failure), decreased stroke volume, and blood pooling that favors thrombus formation.

Myocarditis

Inflammation of the muscular layer of the heart (myocardium) characterized by leukocytic infiltration that causes myocytes to become swollen, necrotic, or degenerated, leading to decreased cardiac output.

Valvular Stenosis

A form of valvular heart disease involving stiffening, thickening, or fusion of valve leaflets that prevents the valve from opening fully, thereby impeding forward blood flow.

Valvular Regurgitation

A valvular defect where incompetent or damaged valve leaflets fail to close properly, allowing backward flow (regurgitation) of blood into the upstream cardiac chamber.

Infective Endocarditis

An infectious process of the endocardial lining and heart valves marked by the growth of infected vegetative lesions (clumps of bacteria, platelets, and fibrin) that can ulcerate leaflets or break off as systemic emboli.

Rheumatic Fever

An autoimmune inflammatory disease developing $2\text{--}4\,\text{weeks}$ after untreated or inadequately treated Group A Streptococcus pharyngitis, manifesting with carditis, polyarthritis, chorea, and subcutaneous nodules, which can produce chronic rheumatic valve scarring.

Systolic Heart Failure

Heart failure primarily characterized by an impaired ejection or squeezing capacity of the ventricles during systole, frequently resulting from conditions such as dilated cardiomyopathy.

Diastolic Heart Failure

Heart failure characterized by impaired ventricular relaxation and filling during diastole due to stiff, thickened walls (such as in hypertrophic cardiomyopathy) despite preserved contractility.

Cardiogenic Shock

A state of severe tissue hypoperfusion caused by primary intracardiac dysfunction and pump failure, where diminished myocardial contractility impairs cardiac output despite adequate circulating volume.

Hypovolemic Shock

Shock resulting from a significant loss of intravascular fluid or whole blood volume, causing decreased venous return, diminished cardiac output, and inadequate tissue perfusion.

Distributive Shock

Shock initiated by profound, abnormal systemic vasodilation and maldistribution of blood flow (triggered by sepsis, anaphylaxis, or neurogenic injury), causing relative hypovolemia and impaired organ perfusion.

Obstructive Shock

Shock caused by physical, non-cardiac mechanical obstruction or restriction to blood flow within the central circulation, leading to critical reductions in venous return and cardiac output.