Blood and Heart

Tunica intima

The inner layer of blood vessel walls.

Tunica media

The middle layer of blood vessel walls.

Tunica adventitia

The outer layer of blood vessel walls.

Veins

Vessels that carry blood to the heart.

Arteries

Vessels that carry blood away from the heart.

Capillaries

Vessels where gas exchange occurs.

Path of blood flow through vascular system

Heart → Arteries → Arterioles → Capillaries → Venules → Veins → Heart.

Valves

Structures in larger veins that prevent the backflow of blood.

Capillaries

The smallest blood vessels that connect arterioles and venules.

Pericardium

The sac around the heart.

Myocardium

The muscular layer of the heart.

Endocardium

The layer that lines the chambers of the heart.

Septum

The structure that divides the heart into right and left sides.

Pulmonary veins

The vessels that bring blood from the lungs to the heart.

Pulmonary artery

The vessel that carries blood from the heart to the lungs.

Vena cava

Vessels that bring blood from the body to the heart; includes superior and inferior vena cava.

Aorta

The vessel that carries blood from the heart to all systems in the body.

Coronary arteries

Vessels that supply nutrients and oxygen to the myocardium.

Left ventricle

The chamber with the thickest wall of the heart.

Chordae tendinae

Structures that prevent the atrioventricular valves from inverting during ventricular contraction.

Apex

The pointed tip of the heart.

Atria

The two superior receiving chambers of the heart.

Ventricles

The two inferior discharging chambers of the heart.

Pulmonary circulation

The circulation that takes blood to the lungs.

Systemic circulation

The circulation that takes blood to the rest of the body.

Trace of blood through the heart

Vena cava → Right atrium → Tricuspid valve → Right ventricle → Pulmonary valve → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta → Body.

Pulmonary veins

The vessels that bring oxygenated blood to the heart.

Pulmonary artery

The vessel that brings deoxygenated blood away from the heart.

Right atrium

The structure receiving blood from the upper and lower vena cavas.

Right ventricle

The structure sending blood to the lungs.

Pulmonary artery

The structure through which deoxygenated blood exits the heart.

Pulmonary veins

The structure through which oxygenated blood enters the heart.

Left ventricle

The structure that pumps blood to the majority of the body.

Left atrium

The heart chamber that receives oxygenated blood.

SA node

The natural pacemaker of the heart.

AV node

A node in the heart's electrical conduction system.

Electrocardiogram (ECG or EKG)

An instrument used to record the electrical currents generated by the heart.

Fibrillation

Uncoordinated contractions of the heart.

Ventricular fibrillation

A more life-threatening condition than atrial fibrillation.

Myocardial infarction

The scientific name for a heart attack.

Systole

The phase of the heart cycle when the heart muscle contracts.

Diastole

The phase of the heart cycle when the heart muscle relaxes.

Systole

During this phase, the heart muscle contracts, pumping blood out of the heart.

Heart sounds LUB

The sound produced by the closing of the atrioventricular valves and contraction of the ventricles.