Ch 18: The Heart Practice Flashcards

A comprehensive set of vocabulary flashcards covering the anatomy, physiology, and electrical activity of the human heart based on lecture notes.

Aristotle's heart theory

The belief that the heart was the source of heat and the brain existed only to cool the blood.

Daniel Hale Williams

A black cardiologist who performed the first open heart surgery in 1893.

Mediastinum

The location within the thoracic cavity where the heart is situated within the pericardial cavity.

Base

The top portion of the heart.

Apex

The pointed bottom tip of the heart that rests on the diaphragm.

Fibrous pericardium

Dense connective tissue that protects the heart, attaches it to surrounding structures, and prevents overfilling.

Serous pericardium

A slippery membrane consisting of a parietal layer deep to the fibrous pericardium and a visceral layer (epicardium) attached to the heart muscle.

Myocardium

The thick middle muscle layer of the heart wall anchored by spiral connective tissue fibers.

Endocardium

The innermost layer of simple squamous epithelium that reduces friction and is continuous with the endothelium.

Interatrial septum

The wall that divides the left and right atria.

Interventricular septum

The wall that divides the left and right ventricles.

Atrioventricular (AV) valves

Valves that separate the atria and ventricles, including the tricuspid and bicuspid (mitral) valves.

Semilunar valves (SL Valves)

Valves located between the ventricles and arteries, including the pulmonary and aortic valves.

Chordae tendineae

Cords attached to valve flaps and papillary muscles that anchor valves to prevent them from turning inside out.

Lub

The first heart sound caused by the closing of the atrioventricular (AV) valves.

Dup

The second heart sound caused by the closing of the semilunar (SL) valves.

Stenotic valve

A valve disorder where the opening is narrowed or the valve does not open fully.

Pulmonary circulation

The circuit that carries blood from the heart to the lungs and back.

Systemic circulation

The circuit that carries blood from the heart to the body tissues and back.

Pulmonary arteries

The only arteries in the body that carry deoxygenated blood, transporting it from the heart to the lungs.

Pulmonary veins

The only veins in the body that carry oxygenated blood, returning it from the lungs to the heart.

Aorta

The vessel through which oxygen-rich blood leaves the heart to enter systemic circulation.

Angina pectoris

Pain caused by brief low blood flow to the myocardium.

Myocardial Infarction (MI)

Also known as a heart attack, it is a blockage of a coronary vessel where dead cells are replaced by scar tissue.

Intercalated discs

Specialized connections containing desmosomes and gap junctions that allow cardiac muscle to act as a functional syncytium.

Automaticity (Autorhythmicity)

The ability of certain cardiac cells to initiate depolarization without input from nerves.

Sinoatrial node (SA node)

The heart's pacemaker located in the right atrium that sets the sinus rhythm at approximately $75 \times 100$ times per minute.

Atrioventricular bundle (AV bundle)

Also known as the Bundle of His, it transmits electrical impulses from the AV node toward the ventricles.

Purkinje fibers

The subendocardial conducting network that causes the ventricles to contract from the apex upward.

P wave

The EKG wave representing atrial depolarization.

QRS complex

The EKG wave representing ventricular depolarization; it also hides atrial repolarization.

T wave

The EKG wave representing ventricular repolarization.

Systole

The phase of the cardiac cycle representing contraction of the heart muscle.

Diastole

The phase of the cardiac cycle representing relaxation of the heart muscle.

End Diastolic Volume

The maximum amount of blood the ventricles hold at the end of the filling phase, right before contraction.

End Systolic Volume

The blood remaining in the ventricles after contraction.

Cardiac Output

Calculated as $CO = HR \times SV$, it is the total amount of blood pumped by a ventricle in one minute.

Stroke Volume (SV)

The amount of blood pumped out by one ventricle in one beat, calculated as $SV = EDV - ESV$.

Frank-Starling law of the heart

The principle stating that increased stretching of the heart muscle (due to venous return) leads to stronger contractions and increased stroke volume.

Tachycardia

A heart rate greater than $100\,bpm$.

Bradycardia

A heart rate slower than $60\,bpm$; normal in athletes but potentially dangerous in others.