Chapter 15: Cardiovascular System - The Heart and Blood Vessels

Comprehensive vocabulary flashcards covering anatomical terms, structures, cardiac cycle phases, conduction pathways, and blood vessel characteristics from Chapter 15.

Base (of the heart)

Wide superior border of the heart that lies just beneath the second rib.

Apex (of the heart)

Inferior point of the heart located at the fifth intercostal space.

Visceral Pericardium (Epicardium)

Innermost delicate simple squamous epithelium over loose/areolar connective tissue covering surrounding the heart muscle.

Parietal Pericardium

Inner simple squamous epithelium over loose/areolar connective tissue lining of the fibrous pericardium.

Fibrous Pericardium

Outermost tough, dense fibrous connective tissue layer that prevents overstretching of the heart.

Pericarditis

Inflammation of the pericardium.

Myocardium

Cardiac muscle tissue that makes up the bulk of the heart wall.

Endocardium

Smooth inner lining of heart chambers that also covers the heart valves.

Endocarditis

Inflammation of the endocardium, which includes mitral valve prolapse.

Atria

Thin-walled upper chambers of the heart that passively receive blood from veins.

Ventricles

Thick-walled lower chambers of the heart that actively pump blood into arteries.

Trabeculae Carneae

Irregular inner surface composed of ridges and folds located within the ventricles.

Atrioventricular (AV) Valves

Valves that prevent regurgitation of blood from the ventricles back into the atria.

Tricuspid Valve

Atrioventricular valve located between the right atrium and right ventricle.

Bicuspid (Mitral) Valve

Atrioventricular valve located between the left atrium and left ventricle.

Mitral Valve Prolapse (MVP)

An infection causing cusp(s) of the mitral valve to erode, leading to incomplete closure.

Chordae Tendineae

Tendon-like, fibrous cords connecting the cusps of AV valves to papillary muscles.

Papillary Muscles

Muscular columns on the inner surface of ventricles that contract and pull on chordae tendineae to prevent valve cusps from swinging backwards.

Pulmonary Semilunar Valve

Semilunar valve located at the base of the pulmonary trunk that prevents backflow of blood.

Aortic Semilunar Valve

Semilunar valve located at the base of the aorta that prevents backflow of blood.

Skeleton of the Heart

Dense regular connective tissue forming rings around the four valves and a mass in the interventricular septum, providing attachment sites for valves and muscle fibers.

Anastomoses

Connections between two or more branches of arteries supplying the same region with blood to provide alternate routes.

Angina Pectoris

Tightening sensation in the chest, usually during strenuous activity, due to blockage of coronary arteries.

Myocardial Infarction

Death of heart muscle tissue resulting from blockage in coronary arteries.

Systole

The contraction phase of the heart chambers in the cardiac cycle.

Diastole

The relaxation phase of the heart chambers in the cardiac cycle.

Lubb

Loud, long first heart sound representing the closing of AV valves during ventricular systole.

Dupp

Short, sharp second heart sound representing the closing of SL valves during ventricular diastole.

Murmur

Sound caused by incomplete closure of valve cusps allowing blood to leak back.

Functional Syncytium

A interconnected network of cardiac muscle fibers that acts and contracts as a single unit.

Sinoatrial (SA) Node

Pacemaker located in the right uppermost atrial wall that rhythmically initiates cardiac impulses $60\text{--}100$ times per minute.

Atrioventricular (AV) Node

Structure located in the interatrial septum that provides a delay signal to allow for ventricular filling.

Atrioventricular (AV) Bundle

The only electrical connection between atria and ventricles, located in the superior interventricular septum.

Purkinje Fibers

Large diameter conduction myofibers within the papillary muscles that conduct impulses into the ventricular myocardium.

Arrhythmia

An irregular heartbeat in rate and/or rhythm.

Tachycardia

A resting heart rate greater than $100\text{ bpm}$.

Bradycardia

A resting heart rate less than $60\text{ bpm}$.

Electrocardiogram (ECG)

A recording of the electrical changes that occur in the myocardium during the cardiac cycle.

P Wave

Small upward ECG wave representing atrial depolarization.

QRS Complex

ECG wave representing the onset of ventricular depolarization.

T Wave

Dome-shaped, upward ECG deflection representing ventricular repolarization.

Hyperkalemia

An excess of potassium ions in the blood, resulting in decreased heart rate and decreased force of contraction.

Hypokalemia

An insufficient amount of potassium ions in the blood that causes arrhythmia.

Angiogenesis

The formation of blood vessels occurring throughout life.

Tunica Interna

Innermost blood vessel layer surrounding the lumen, composed of endothelium, basement membrane, and internal elastic lamina.

Tunica Media

Thickest blood vessel layer composed of smooth muscle cells and elastic fibers.

Tunica Externa

Outermost blood vessel layer composed of elastic and collagen fibers.

Vasoconstriction

Contraction of vessel smooth muscle that decreases vessel volume, decreases blood flow, and increases blood pressure.

Vasodilation

Relaxation of vessel smooth muscle that increases vessel volume, increases blood flow, and decreases blood pressure.

Continuous Capillaries

Capillaries with small openings (slits) between endothelial cells forming an uninterrupted ring around the lumen.

Fenestrated Capillaries

Capillaries with larger openings containing pores (fenestrae) that allow higher permeability.

Sinusoids

Capillaries with the largest openings between endothelial cells that allow passage of cells across the wall.

Precapillary Sphincters

Smooth muscles that control blood entry into capillary beds based on the metabolic needs of tissue.

Atherosclerosis

An arterial disease resulting from the accumulation of soft masses of fatty materials (plaque), especially cholesterol, on the inside of the artery wall.

Pulse

The pressure wave that travels through arteries following left ventricular systole.

Cardiac Output (CO)

The volume of blood pumped by each ventricle each minute, defined mathematically as $\text{CO} = \text{HR} \times \text{SV}$.

Stroke Volume (SV)

The amount of blood pumped out of the heart per ventricular systole.

Peripheral Resistance (PR)

The opposition to blood flow primarily due to friction.

Frank-Starling Law of the Heart

Principle stating that the strength of contraction, and therefore stroke volume, increases as venous return (preload) increases.

Central Venous Pressure

The pressure of blood in the right atrium after atrial systole.