The Heart

Pulmonary circuit

Blood flow to and from the gas exchange surface of the lung

Systemic circuit

transport blood to and from the rest of the body

Arteries

or efferent vessels that carry blood away from the heart

Arterioles

last small branches of the arterial system with control valves to capillaries

Capillaries

small, thing walled vessels originating from the arterioles that permit exchange of nutrients

Venules

collect blood from the capillaries

Veins

or afferent vessels that carry blood to the heart from the venules

Right atrium

The upper right chamber of the heart, where deoxygenated blood is received from the vena cava and then sent to the right ventricle.

Right ventricle

the chamber on the right side of the heart that receives venous blood from the right atrium and pumps it into the pulmonary trunk (pulmonary circuit)

Left atrium

the left upper chamber of the heart that receives blood from the pulmonary veins and empties it to the left ventricle

Left ventricle

the chamber on the left side of the heart that receives arterial blood from the left atrium and pumps it into the aorta (systemic circuit)

Heart Base

area of outflow valves, fairly cranial; superior end of the heart

Heart Apex

area of mitral valve (L) and tricuspid valve (R); inferior pointed tip of the heart

Pericardial cavity

the space between the layers of the pericardium (parietal and visceral) that contains fluid that lubricates the membrane surfaces and allows easy heart movement

Mediastinum

partition that separates the thorax into two compartments (that contain the right and left lung) and encloses the heart, esophagus, trachea, and thymus gland

Visceral pericardium

or epicardium covers the outer surface of the heart

Parietal pericardium

Membrane that forms the inner layer of the pericardial sac which sorrounds the heart

Pericardial fluid

found in the pericardial cavity, exuded by the serous pericardium, lubricates the membranes and allows the heart to beat almost without friction; isolates the heart from other organs, allows the heart room to expand and yet prevents excessive expansion

Auricle

wrinkled pouch on anterior surface of each atrium, slightly increases the capacity of an atrium so that it can hold a greater volume of blood

Coronary sulcus

This is the name of the groove or depression between the atria and the ventricles and it is in part of this sulcus that we find the coronary sinus. We find some of the larger coronary arteries and veins in this groove.

Interventricular sulcus

mark the septum that separates the right and left ventricles

Epicardium

the external layer of the heart (visceral pericardium) and the inner layer of the pericardium

Myocardium

The middle layer of the muscle. It is thick and composed of cardiac muscle tissues and associated connective tissues, blood vessel , and nerves. This layer produces the heart contraction.

Endocardium

smooth layer of cells that lines the insides of the heart (simple squamous epithelium) and is continuous with the insides of the blood vessels; allows for smooth blood flow

Cardiac muscle tissue

Cardiac muscle cells are small, have a single nucleus, have branching interconnection between cells, and have intercalated disc connecting individual cells

Interatrial septum

muscular wall sepatating the two atria

Interventricular septum

muscular wall separating the two ventricles

Atrioventricular valves

one way valves between the atria and ventricles

Superior vena cava

large vein that brings oxygen-poor blood from the upper part of the body to the right atrium

Inferior vena cava

vein that receives blood from lower limbs and abdominal organs and empties into the posterior part of the right atrium of the heart

Coronary sinus

enlarged vein from junctions of all cardiac veins which empty into the right atrium

Foramen ovale

penetrates interatrial septum from fifth week of embryonic development until birth

Fossa ovalis

A small depression left in the interartrial septum as a result of the closure of the foramen ovale after birth

Right atrioventricular valve

AKA the tricuspid valve. Allows blood to flow from the right atrium into the right ventricle. It is bounded by three fibrous flaps called cusps and is located between the right atrium and the right ventricle.

Chordae tendinae

cord-like tendons that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart.; connected to papillary muscles

Papillary muscles

Finger like or coned shaped muscular projections located on the inner surface of the ventricles

Pulmonary trunk

the artery that carries venous blood from the right ventricle of the heart and divides into the right and left pulmonary arteries

Pulmonary semilunar valve

Valve that lies between the right ventricle and the pulmonary artery and has 3 cusps. Blood flows from the right ventricle throught the pulmonary valve to become oxygenated

Pulmonary arteries

arteries that carry deoxygenated blood from the heart (pulmonary trunk) to the lungs (left and right)

Pulmonary veins

vessels that carry oxygenated blood from the lungs to the left atrium

Left atrioventricular valve

located between the left atrium and left ventricle - prevents backflow - also known as mitral valve and bicuspid valve

Aortic semilunar valve

located between the aorta and the left ventricle to prevent the backflow of blood

Ascending aorta

the ascending part of the aorta as it emerges from the left ventricle

Aortic arch

the part of the aorta that curves before becoming the descending aorta

Descending aorta

the descending part of the aorta that branches into the thoracic and abdominal aortae

Coronary circulation

circulation of blood through the coronary blood vessels to deliver oxygen and nutrients to the heart muscle tissue

Right coronary artery

originates at the base of the ascending aorta and supplies the right atrium, and portion of both ventricles.

Posterior interventricular artery

branch of the right coronary artery that runs in the post interventricular sulcus and supplies this septum and adjacent portions of ventricles

Left coronary artery

originates at the base of the aorta and supplies the left ventricle, left atrium, and interventricular septum

Circumflex artery

curves left around coronary sulcus and fuses with branches of the RCA

Anterior interventricular artery

(know clinically as the left anterior descending artery), branch of left coronary artery; travels down anterior interventricular sulcus toward apex; supplies interventricular septum and anterior walls of ventricles

Arterial anastomoses

When two arteries merge and provide alternative routes of blood supply to a tissue:

Great cardiac vein

The anterior vein of the heart that runs in the interventricular sulcus, and feeds into the coronary sinus at its left end

Coronary sinus

The great, middle, and small cardiac veins all empty into here, which in turn empties into the right atrium.

Middle cardiac vein

vein that drains the area supplied by the posterior interventricular artery

Contractile cells

Produce the powerful contractions that propel blood

Conducting cells

specialized muscle cells of the conducting system which coordinates the heart beat

Cardiac cycle

the complete cycle of events in the heart from the beginning of one heart beat to the beginning of the next

Automaticity

The ability of the heart to generate and conduct electrical impulses on its own in the absence of neural or homonal stimulation

Conducting system

connect the SA and AV nodes and distributes the contractile stimulus

SA node

the pace-maker of the heart; where the impulse conduction of the heart usually starts; located in the top of the right atrium

AV node

an area of specialized tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles.

Conducting cells

the cells responsible for initiating and distributing the stimulus to contract

AV bundle

travels along interventricular septum before dividing into left and right bundle branches

Purkinje fibers

The smallest (and final) fibers in the cardiac conduction system. The Purkinje fibers transmit the cardiac impulse to the ventricular myocardium

Systole

the period in which a chambers pushes blood into another chamber or into an arterial trunk

Diastole

the relaxation phase when the chambers fill with blood in preparation for the next cycle

Phases of the cardiac cycle

Atrial systole, ventricular systole, and ventricular diastole

Cardiodynamics

refers to the movements and forces generated during cardiac contractions

Stroke volume

the amount of blood ejected by each ventricle during a single heart beat

Cardiac output

amount of blood pumped by each ventricle in one minute