Cardiovascular System

Angio-

Vessel

Ather-

Porridge

Brady-

Slow

Diastol-

Dilation

Edem-

Swelling

-gram

Something written

Lun-

Moon

Myo-

Muscle

Papill-

Nipple

Phleb-

Vein

Scler-

Hard

Syn-

Together

Systol-

Contraction

Tachy-

Rapid

Cardiovascular System

Consists of the heart and blood vessels

Heart

Muscular pump that generates the force required to move blood through the body’s blood vessels.

Blood Vessels

The organ that transports the blood.

Veins

Vessels that carry blood to the heart.

Arteries

Vessels that carry blood away from the heart.

Capillaries

Gas, nutrient, and waste exchange occur in the microscopic blood vessels that lie between arteries and veins.

Pulmonary Circuit

System of blood vessels that transports blood between the heart and the lungs. Sends deoxygenated blood to the lungs to unload carbon dioxide and pick up oxygen.

Systemic Circuit

System of blood vessels that transports blood between the heart and all body tissues except the lungs. Sends oxygenated blood and nutrients to all body cells and removes waste.

Pericardium

Connective tissue surrounding the heart.

Fibrous Pericardium

Outermost connective tissue that covers and anchors the heart. It is a tough, protective outer fibrous bag.

Visceral Pericardium (Epicardium)

Inner serous membrane covering the heart surface.

Parietal Pericardium

Outer serous membrane covering the heart surface. Covers the inner surface of the fibrous pericardium.

Pericardial Cavity

The space between the parietal and visceral serous layers of the pericardium. Contains a small volume of serous fluid (pericardial fluid).

Heart Location

Between the lungs, posterior to the sternum, above the diaphragm. In a region called the mediastinum of the thoracic cavity.

Pericardial Fluid

Serous fluid in the pericardial cavity that reduces friction between the visceral and parietal pericardium as the heart moves within them.

Myocardium

Thick middle layer of the heart wall. Consists mostly of the cardiac muscle tissue that pumps blood out of the heart chambers.

Endocardium

Inner layer of the heart wall. Consists of epithelium and underlying connective tissue that contains many elastic and collagen fibers. Lines all of the heart chambers and covers the structures that project into them.

Atria

The two upper chambers of the heart. Have thin walls and receive blood returning to the heart.

Auricles

Small, earlike projections extending anteriorly from the atria. They serve to increase the blood volume capacity of the atria.

Ventricles

The lower chambers of the heart. Receives blood from the atria and contract to force blood out of the heart into arteries.

Interatrial Septum

A thin wall that separates the right and left atrium. As a result, blood from the right side of the heart never mixes with blood from the left side.

Interventricular Septum

A thick wall that separates the right and left atrium. As a result, blood from the right side of the heart never mixes with blood from the left side.

Venae Cavae

One of two large veins that conveys oxygen-poor blood to the right atrium.

Coronary Sinus

A smaller vein that drains venous blood into the right atrium from the myocardium of the heart.

Atrioventricular Valve (AV Valve)

Cardiac valve between an atrium and a ventricle. Ensures one-way blood flow between the atrium and ventricle on each side.

Tricuspid Valve (Right Atrioventricular Valve)

Heart valve located between the right atrium and the right ventricle. Permits blood to move from the right atrium into the right ventricle and prevents it from moving in the opposite direction.

Chordae Tendineae

Strong fibrous strings that attach to the cusps of the tricuspid valve and originate from small mounds of cardiac muscle tissue (papillary muscles).

Papillary Muscle

Any of the muscles that extend inward from the ventricular wall of the heart to which the chordae tendineae attatch.

Pulmonary Trunk

Divides to form the left and right pulmonary arteries that lead to the lungs.

Pulmonary Valve

Valve leading from the right ventricle to the pulmonary trunk (pulmonary semilunar valve).

Mitral Valve

Heart valve between the left atrium and left ventricle (bicuspid valve). Prevents blood from flowing back into the left atrium from the left ventricle when the ventricle contracts.

Mitral Valve Prolapse (MVP)

One or both of the cusps of the mitral valve stretches and bulges into the left atrium during ventricular contraction.

Aorta

Major systemic artery that receives blood directly from the left ventricle.

Aortic Valve

Valve in the aorta near its origin that prevents blood from returning to the left ventricle of the heart. It opens and allows blood to leave the left ventricle as it contracts.

Coronary Arteries

Arteries that supply blood to the wall of the heart.

Cardiac Veins

Any of the blood vessels that returns blood from the venules of the myocardium of the coronary sinus.

Coronary Sinus

Large vessel on the posterior surface of the heart into which the cardiac veins drain.

Skeleton of the Heart

Composed of dense connective tissue rings, provides a firm attachment for the heart valves and muscle fibers, and prevents the outlets of the atria and ventricles from dilating during contraction.

Systole

Contraction of the heart chambers.

Diastole

Relaxation of the heart chambers.

Cardiac Cycle

Sequence of myocardial contraction and relaxation that constitutes a complete heartbeat.

Intercalated Discs

Connection between cardiac muscle cells that includes gap junctions. The cell membranes at the intercalated discs are highly folded to increase contact between cells.

Desmosomes

Within intercalated discs are intercellular junctions that withstand tension and hold cells together.

Gap Junctions

Enable action potentials to spread throughout a network of cells.

Functional Synctium

A mass merging of cells performing as a unit. Those of the heart are joined electrically.

Cardiac Conduction System

System of specialized cardiac muscle fibers that conduct cardiac impulses from the SA node throughout the myocardium.

Sinoatrial Node (SA Node)

A mass of specialized, noncontractile cells just beneath the epicardium in the right atrium near the opening of the superior vena cava.

Pacemaker

Mass of specialized cardiac muscle tissue that controls the rhythm of the heartbeat (sinoatrial node).

Internodal Atrial Muscle

Bundles of atrial muscle.

Atrioventricular (AV) Node

Specialized mass of cardiac muscle fibers in the interatrial septum of the heart that conducts cardiac impulses from the sinoatrial node to the AV bundle. It provides the only normal conductive pathway between atrial and ventricular syncytia.

Atrioventricular (AV) Bundle

Group of specialized muscle fibers that conducts impulses from the atrioventricular node to the subendocardial conducting network (Purkinje fibers) in the ventricular muscle of the heart.

Purkinje Fibers

Also called Subendocardial conducting network. Conduct the impulse to distant regions of the massive ventricular myocardium faster than cell-to-cell conduction could.

Electrocardiogram (ECG/EKG)

Recording of electrical activity associated with the cardiac cycle.

Ventricular Depolarization

When cardiac impulse reaches the ventricular cells, they rapidly depolarize. The ventricular myocardium is thicker than those of the atria, so the electrical change and deflection are both greater.

QRS Complex

When the electrical change ends, the pen returns to the baseline leaving a pattern usually consisting of a downward deflection. Represents ventricular depolarization.

Q Wave

Downward Deflection.

R Wave

Large upward, triangular spike.

S Wave

Ends as a downward deflection.

Atrial Repolarization

Occurs during the time of the ventricular depolarization, but the electrical change is small and therefore obscured by the electrical changes occurring in the ventricles, so it is not seen in an ECG tracing.

P Wave

First positive deflection on the ECG. Smaller in amplitude because they represent atrial depolarization. Top chambers getting ready to pump.

T Wave

Positive deflection on the ECG. Represents ventricular repolarization. Lower chambers resetting.

Aortic Sound

Comes from the right.

Pulmonic Sound

Comes from the left.

Murmur

An abnormal sound produced by the cusps not closing completely, and blood leaking back through the valve.

Heart Murmur

Can be heard when there is stenosis (stiffening) of the mitral valve cusps, which narrows the opening and reduces the amount fo blood that can go into the relaxed left ventricle.

lubb-dupp Sound

The sound the heart makes through a stethoscope.

Lubb-

Sound that occurs as the AV valve closes during ventricular diastole.

-Dupp

Sound that occurs as when the semilunar valves close during ventricular diastole.

Arrhythmia

Fast or irregular heartbeats.

Fibrillation

Small areas of the myocardium contract into an uncoordinated, chaotic fashion.

Tachycardia

Abnormally fast heartbeat (usually more that 100 bpm at rest).

Bradycardia

Slow heart rate (usually fewer than 60 bpm).

Premature Beat

Occurs before it is expected in a normal series of cardiac cycles.

Vagus Nerves

Supply parasympathetic fibers to the heart.

Accelerator Nerves

Supply sympathetic fibers to the heart.

Arteries

Strong, elastic vessels adapted for transporting blood away from the heart under relatively high pressure

Arterioles

Small branches of arteries that communicate with a capillary network.

Vasoconstriction

Decrease in the diameter of a blood vessel.

Vasodilation

Increase in the diameter of a blood vessel.

Tunica Interna

Innermost layer of the wall of an artery. Consists of simple squamous epithelium, or endothelium, and an underlying connective tissue containing collagen and elastic fibers.

Tunica Media

Thick middle layer of the wall of an artery. Consists of circular smooth muscle and elastic connective tissue.

Tunica Externa

This outermost layer of the wall of an artery. Consists of connective tissue.

Capillaries

The smallest diameter blood vessels, most often connect the smallest arterioles and the smallest venules.

Capillary Wall

Only consists of endothelium, which is a simple squamous epithelium.

Function of a Capillary

Exchange substances, such as oxygen, carbon dioxide, and nutrients, between the blood and the tissue fluid that surrounds the cells.

Precapillary Sphincters

Regulates blood flow into capillaries. Small bands of smooth muscle that wrap around the beginning of the capillaries. The sphincters constrict the capillaries as they contract, and dilate them as they relax.