Heart

cardiovascular system

heart, blood vessels, blood

the heart beats

about 100,000 times a day

heart pumps

8000 L of blood a day

pulmonary circuit

carries blood to the lungs for gas exchange and returns it to the heart

systemic circuit

Circuit of blood that carries blood between the heart and the rest of the body.

Each circuit begins and ends at the heart

blood travels through these circuits in sequence

types of blood vessels

arteries, veins, capillaries

arteries

carry blood away from the heart

veins

return blood to the heart

Capillaries (exchange vessels)

Interconnect smallest arteries and smallest veins, Exchange dissolved gases, nutrients, and wastes between blood and surrounding tissues

four chambers of the heart

right atrium, right ventricle, left atrium, left ventricle

right atrium

receives blood from systemic circuit

right ventricle

pumps blood into the pulmonary circuit

left atrium

receives blood from pulmonary circuit

left ventricle

pumps blood into the systemic circuit

great vessels connect at

base (superior)

pointed tip of heart

apex (inferior)

Mediastinum

area between the lungs containing the heart, aorta, venae cavae, esophagus, and trachea

pericardium

surrounds the heart

Pericardium consists of

fibrous pericardium and serous pericardium

inner serous pericardium

outer parietal layer and inner visceral layer

pericardial cavity

between parietal and visceral layers, contains pericardial fluid

pericarditis

inflammation of the pericardium

cardiac tamponade

restricted movement of the heart due to excess fluid in pericardial cavity

Superficial Anatomy of the Heart

atria and sulci

Two thin-walled atria

Each with an expandable outer auricle

sulci (grooves)

contain fat and blood vessels

coronary sulcus

marks the border between the atria and ventricles.

anterior interventricular sulcus

marks the boundary between the ventricles anteriorly

posterior interventricular sulcus

marks the boundary between the ventricles posteriorly

The heart wall consists of three layers:

epicardium, myocardium, endocardium

epicardium (visceral pericardium)

the inner layer of the pericardium that covers the surface of the heart

myocardium

cardiac muscle tissue

endocardium

membrane lining the cavities of the heart

connective tissues of the heart

provide physical support for cardiac muscle fibers, blood vessels, and nerves of the myocardium, help distribute the forces of contraction, add strength and prevent overexpansion of the heart, provide elasticity that helps return the heart to its original size

cardiac skeleton

Four bands around heart valves and bases of pulmonary trunk and aorta, Stabilize valves, Electrically insulate ventricular cells from atrial cells

internal anatomy and organization

Chambers of heart are separated by muscular partitions (septa) (Interatrial septum, Separates atria, Interventricular septum, Separates ventricles, Much thicker than interatrial septum)

atrioventricular valves

tricuspid and mitral valves

atrioventricular valves

Valves located between the atrial and ventricular chambers on each side of the heart, prevent backflow into the atria when the ventricles are contracting.

semilunar valves

pulmonary and aortic valves located between the right ventricle and the pulmonary artery and between the left ventricle and the aorta

right atrium receives blood from

superior and inferior vena cava

foramen ovale

Before birth, is an opening through interatrial septum , Connects the two atria, Seals off at birth, forming fossa ovalis

pectinate muscles

prominent muscular ridges in the anterior atrial wall and the inner surface of the auricle

blood flows from

right atrium and right ventricle

tricuspid valve (right AV valve)

3 leaflets, Prevents backflow from the Right Ventricle to the Right Atrium

chordae tendineae

thin bands of fibrous tissue that attach to the valves in the heart and prevent them from inverting

papillary muscles

responsible for pulling the atrioventricular valves closed by means of the chordae tendineae

trabeculae carneae

muscular ridges on the internal surface of the ventricles

moderator band

muscular band of heart tissue that carries a portion of the right bundle branch

conus arteriosus (infundibulum)

the upper smooth-walled portion of the right ventricle, which leads to the pulmonary trunk

left atrium

receives blood from pulmonary veins

mitral valve

A valve in the heart that guards the opening between the left atrium and the left ventricle; prevents the blood in the ventricle from returning to the atrium. Alternative name is bicuspid valve.

left ventricle

receives oxygen-rich blood from the left atrium

aortic sinuses

saclike expansions at base of ascending aorta

aortic arch

curve of the aorta

Compared to left ventricle, the right ventricle

Holds and pumps the same amount of blood, Has thinner walls, Develops less pressure, Is more pouch-shaped than round

heart valves

prevent back flow of blood

atrioventricular valves

between atria and ventricles

when ventricles contract

-AV valves close as blood attempts to back up into the atria \> pressure rises inside of the ventricles \> semilunar valves open and blood flows into great vessels

semilunar valves

Pulmonary and aortic valves, Prevent backflow of blood into ventricles

Valvular Heart Disease (VHD)

When valve function has deteriorated to where heart cannot maintain adequate blood flow

carditis

inflammation of the heart

rheumatic fever

A bacterial infection that can be carried in the blood to the joints

coronary circulation

supplies blood to the muscle tissue of the heart

coronary arteries

originate at the base of the ascending aorta, and each gives rise to two branches.

Right Coronary Artery (RCA)

supplies blood to the right atrium, right ventricle, bottom portion of the left ventricle and back of the septum

right coronary artery gives rise to

marginal artery and posterior interventricular artery

left coronary artery (LCA)

supplies blood to the left ventricle, left atrium, and interventricular septum

left coronary artery gives rise to

anterior interventricular artery and circumflex artery

arterial anastomoses

provide alternate pathways (collateral channels) to ensure continuous flow, even if one artery is blocked

cardiac dominance

term referring to the origin of the posterior interventricular artery

cardiac veins

great cardiac vein, middle cardiac vein, small cardiac vein

great cardiac vein

drains blood from area of anterior interventricular artery into coronary sinus

Empty into great cardiac vein or coronary sinus

Posterior cardiac vein, middle cardiac vein, and small cardiac vein

anterior cardiac veins empty

directly into the right atrium

coronary artery disease

areas of partial or complete blockage of coronary circulation

cardiac muscle cells

are maintained by an extensive capillary network.

coronary ischemia

lack of blood flow to the heart muscle due to a blockage

coronary artery disease cause

Exact cause unknown, Plaque begins to form because the inner lining of the artery (endothelium) becomes damaged. Three possible causes of damage to the arterial wall are:

-Elevated levels of cholesterol and triglycerides in the blood

-High blood pressure

-Cigarette smoking

angina pectoris

chest pain, which may radiate to the left arm and jaw, that occurs when there is an insufficient supply of blood to the heart muscle

myocardial infarction

condition characterized by dead tissue areas in the myocardium; caused by interruption of blood supply to the area.

coronary thrombosis

damage to the heart muscle caused by a thrombus blocking a coronary artery

heartbeat

A single cardiac contraction, All heart chambers contract in series: First the atria, Then the ventricles

Two types of cardiac muscle cells

autorhythmic cells and contractile cells

autorhythmic cells

are also called pacemakers because they set the rate of the heartbeat.

contractile cells

produce contractions that propel blood

conducting system

consists of specialized cardiac muscle cells

initiate and distribute electrical impulses that stimulate contraction

autorhythmicity

heart's ability to control its own contractions

pacemaker cells found in

SA node and AV node

sinoatrial node location

wall of right atrium

atrioventricular node location

junction of atria and ventricles

conducting cells found in

Internodal pathways of atria, Atrioventricular (AV) bundle, bundle branches, and Purkinje fibers of ventricles

Electrocardiogram (ECG)

recording of the electrical changes that occur in the myocardium during a cardiac cycle

p wave

depolarization of the atria

qrs complex

depolarization of the ventricles

t wave

repolarization of ventricles