Cardiac Muscle and Blood

Systole

The phase of the heartbeat when the chambers are contracting.

Diastole

The phase of the heartbeat when the chambers are at rest.

Heart Sound "lub" (S1)

The sound produced when the mitral and tricuspid valves close.

Heart Sound "dub" (S2)

The sound produced when the aortic and pulmonic valves close.

S3 Heart Sound

Produced during early diastole filling of the heart chambers.

S4 Heart Sound

Produced during late diastole atrial contraction.

Heart Murmurs

Abnormal sounds resulting from incomplete valve closure that causes abnormal blood flow.

Foramen Ovale

An opening between the atria in fetal hearts that closes after birth.

Ductus Arteriosus

A shunt between the pulmonary artery and aorta that closes after birth, functioning as a ligament.

Coronary Vessels

Blood vessels that supply blood to the heart muscle; the heart receives blood first.

Major Vessels of the Neck

Includes the subclavian artery and the common carotid artery.

Capillaries

The smallest blood vessels where gas and nutrient exchange occurs.

Blood Composition

Made up of plasma, erythrocytes, leukocytes, and thrombocytes.

Sickle Cell Anemia

A genetic condition that leads to pain, anemia, and infections due to abnormal red blood cells.

P-Wave

Represents atrial depolarization in an ECG.

QRS Complex

Represents ventricular depolarization in an ECG.

T-Wave

Represents ventricular repolarization in an ECG.

Sinoatrial (SA) Node

The heart's pacemaker responsible for initiating the heartbeat.

Cardiac Muscle Structure

Contains actin and myosin, has a branched structure, with intercalated discs for cell communication.