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