Chapter 16: Anatomy of the Heart

Three layers of the pericardium

Visceral pericardium, parietal pericardium, and pericardial space or pericardial cavity

What happens when a heart valve becomes leaky?

a leaky, or incompetent, valve allows blood to leak back into the chamber from which it has just been pumped.

Two types of shunts

a left-to-right shunt and a right-to-left shunt

Purkinje Fibers

are distributed throughout the ventricular myocardium. They conduct the cardiac impulse very rapidly throughout the ventricles, thereby ensuring a coordinated contraction of both ventricles.

Ventricles

are the lower chambers and pump blood out of the heart

Atria

are the upper chambers and receive the blood into the heart

Pericardium

it attaches the heart to surrounding structures, such as the diaphragm and the large blood vessels that attach to the heart.

Great Vessels

large vessels attached to the heart which includes the superior and inferior venae cavae, pulmonary artery, four pulmonary veins, and the aorta

Troponin

leaks out of the necrotic myocardium into the blood. the leaked enzymes provide valuable diagnostic tool for heart attacks.

All structures that carry oxygenated blood are red

left heart

Blood is shunted from the left heart to the right heart it is called

left-to-right shunt

Atrioventricular Valves

located between the atria and the ventricles. blood flows from the atria through the AV valves into the ventricles. AV valves, which look like basketball nets, are entrance valves because they allow blood to enter the ventricles.

Aortic Valve

located between the left ventricle and aorta. opens and flows into the aorta. when the left ventricle relaxes, the aortic valve snaps closed and prevents any back flow of blood from the aorta into the ventricle.

The Heart sits within the

mediastinum

Abnormal heart sounds are called

murmurs

Angina is often relieved by rest and the administration of drugs such as

nitroglycerin and beta-adrenergic blockers that decrease the work of the heart

Right coronary artery

nourishes the right side of the heart, especially the right ventricle. it also supplies the blood to the parts of the electrical conduction, including the SA node and the AV node

The SA node is called the

pacemaker

The heart is supported by a slinglike structure called the

pericardium

Two semilunar valves (exit valves)are the

pulmonic and aortic semilunar valves

Inferior Vena Cava

receives blood from the lower part of the body

Left Ventricle

receives oxygenated blood from the left atrium

Right Ventricle

receives unoxygenated blood from the right atrium

Automaticity

refers to the ability of cardiac pacemaker cells to generate their own electrical signal with no help from extrinsic nerves coming from the central nervous system.

P-R interval

represents the time it takes for the cardiac impulse to travel from the atria to the ventricles

Two main coronary arteries

right and left coronary arteries

All structures that carry unoxygenated blood are blue

right heart

The pulmonic semilunar valve is also called the

right semilunar valve

Blood is shunted from right heart to left heart it is called

right-to-left shunt

Septa

separates the right and the left heart

Interatrial Septum

separates the two atria

Interventricular Septum

separates the two ventricles

The conduction system consists of:

sinoatrial node, the atrial conducting fibers, the atrioventricular node and the His-Purkinje system

Narrowing of the valve is called

stenosis

The electrical signal is called

the action potential or the cardiac impulse

Precordium

the area of the anterior chest wall overlying the heart and great vessels

Apex

the lower more pointed end of the heart and is located at the level of the fifth intercostal space.

Three important coronary blood flow characteristics

-coronary blood flow can increase -greatest during myocardial relaxation -can form anastomoses or multiple connections between the arteries.

The left AV valve is called the

Bicuspid Valve or the Mitral Valve

Pericarditis is characterized by pain and a sound

Friction rub

The pericardial membranes become inflamed; this condition is called

Pericarditis

These branches send out numerous long fibers called

Purkinje fibers

Left Heart

Receives the oxygenated blood from the lungs and pumps it to all the organs of the body. The left heart is colored red.

Right Heart

Receives unoxygenated blood from the superior and inferior venae cavae, large veins that collect blood from all parts of the body (the right heart is colored blue).Pumps blood to the lungs, where the blood is oxygenated.

Pathway of Blood Flow Through The Heart

Right atrium from the venae cavae tricuspid valve right ventricle pulmonic valve pulmonary artery right and left pulmonary capillaries(oxygen) four pulmonary veins left atrium bicuspid(mitral) valve left ventricle aortic valve aorta

The first heart sound is called

S1(lubb)

The second heart sound is called

S2(dubb)

Extra sounds are

S3 S4

The rhythm of the heart is disturbed; the heart is then said to be

dysrhythmic

If the electrical signal originates outside of the SA node, it is referred to as

ectopic

ECG

electrical events are recorded

The Heart is made up of three layers of tissue:

endocardium, myocardium, and epicardium

Firing of the SA node sets the rate at which the

heart beats or contracts and relaxes

Shunt

is a passageway that diverts blood from its normal pathway.

Left Atrium

is a thin-walled cavity that receives oxygenated blood from the lungs through four pulmonary veins

Right Atrium

is a thin-walled cavity that receives unoxygenated blood from the superior and inferior venae cavae

Sinoatrial (SA) node

is an electrical signal originates within the SA node.

Conduction System

is located within the walls and septum of the heart.

Endocardium

is the heart's innermost layer. it also lines the valves and is continuous with the blood vessels that enter and leave the heart. the smooth and shiny surface allows blood to flow over it easily.

Aorta

is the largest artery of the body

Epicardium

is the thin outermost layer of the heart. also helps form the pericardium.

Function of the Heart

is to pump and force blood through the blood vessels of the body, providing every cell in the body with vital nutrients and oxygen.

Function of the Left Ventricle

is to pump blood into the systemic circulation. blood leaves the left ventricle through the Aorta

Function of the Right Ventricle

is to pump blood through the pulmonary arteries to the lungs.

The purpose of the AV node is twofold:

1) acts as a path for the cardiac impulse to travel from the atrial conducting fibers into the ventricular bundle of His, and 2) the AV node slows the cardiac impulse as it moves through the AV node into the bundle of His.

Cardiac Conduction System

Both atria must contract, forcing blood into the relaxed ventricles. Then, the ventricles contract, forcing blood out of the heart.

The inflamed pericardial membranes also secrete excuse serous fluid into the pericardial space called

Pericardial effusion

Cardiac Tamponade

The heart is unable to pump a sufficient amount of blood to the body

The path that blood follows from the right side of the heart to and through the lungs and back to the left side of the heart is called

The pulmonary circulation

The bundle of His divided into two branches:

The right and left bundle branches

The path that the blood follows from the left heart to all the organs of the body and back to the right heart is called

The systemic circulation *larger of the two circulations

The right AV valve is called

Tricuspid Valve

Pulmonic Semilunar Valve

between the right ventricle and pulmonary artery. it prevents the blood from flowing back into the right ventricle

Left coronary artery

branches into the left anterior descending (LAD) artery and the circumflex artery. these arteries carry blood to the left side of the heart, especially the left ventricular wall and interventricular septum.

Ventricular Septal Defect

causes the left ventricle to do two things: it pumps blood into the aorta; it also pumps blood into right ventricle through the hole in the septum.

Angina

chest pain

Superior Vena Cava

collects blood from the head and upper body region

Semilunar Valves

control the outflow of blood from the right and left ventricles and are therefore exit valves.

The arteries supplying the myocardium are called

coronary arteries

Left-to-right shunt

diverts blood from the left heart to the right heart it can be illustrated by a child with a hole in the interventricular septum.

Right-to-left shunt

diverts blood from the right to the left heart;it is illustrated by a child who has VSD and a stenotic pulmonic semilunar valve. left ventricle now contains unoxygenated blood into systemic circulation patient appears cyanotic

Cardiology

the study of the heart

Base

the upper flat portion of the heart and is located at the level of second rib.

The heart sounds are made by

the vibrations caused by the closure of the valves

Chordae Tendinaea

tough fibrous bands of tissue. the stretched chordae tendinaea hold on to the cusps and prevent them from blowing though into the atria, like an inside-out umbrella

A regulator myocardial protein is called

troponin

Four chambers of the heart

two atria and two ventricles

If a ventricle is forced to overwork, it will eventually enlarge a condition called

ventricular hypertrophy

Bicuspid Valve

when its open, blood flows from the left atrium into the left ventricle. when the left ventricle contracts, the mitral valve closes and prevents the flow of blood from the left ventricle bak into the left atrium.

Tricuspid Valve

when the valve is open, blood flows from the right atrium into the right ventricle. closes and prevents blood from flowing back into the right atrium.

If coronary blood flow diminishes, the myocardium experiences oxygen deprivation

which is ischemia