Serve as sites of exchange, either between the blood and the air sacs (alveoli) of the lungs or the blood and body cells.
Transports blood directly to and from the chambers of the heart, they are continuous with each chamber.
Receives deoxygenated blood from the right ventricle, and the aorta. Splits into the pulmonary arteries.
Superior vena cava and inferior vena cava
large veins that deliver blood to the atria on the more posterior aspect of the heart. Drains deoxygenated blood into the right atrium.
Atrioventricular (AV) valves
Valves located between the atrium and ventricle of each side of the heart.
Right AV valve
Also called the tricuspid valve. Located between the right atrium and the right ventricle.
Left AV valve
Also called the bicuspid valve or mitral valve. Located between the left atrium and left ventricle.
Valves that mark the boundaries between a ventricle and its associated arterial trunk.
Conveys deoxygenated blood from the right side of the heart through the blood vessels to the lungs for the pickup of oxygen and the release of carbon dioxide, and then back through blood vessels to the left side of the heart.
A condition where equal amounts of blood are normally pumped by the two ventricles through the two circulations.
May occur if the right atrium is impaired. If the right ventricle cannot keep up with the left ventricle more blood remains in the systemic circulation.
May occur if the left ventricle pumps less blood than the right side of the heart. Here additional blood remains in the pulmonary circulation because the left side of the heart receives blood from the lungs.
Right atrium, right AV valve, right ventricle, pulmonary semilunar valves, pulmonary trunk, pulmonary capillaries, pulmonary veins, left atrium, left AV valve, left ventricle, aortic semilunar valve, aorta, systemic circulation, superior and inferior vena cava, right atrium.
Trace the path of blood through the heart, starting at the right atrium, including valves and vessels.
Location of the heart posterior to the sternum left of the body mid-line between the lungs.
Tough dense irregular connective tissue layer that is the outer portion of the pericardial sac.
Parietal layer of the serious pericardium
Serous membrane that is the inner portion of the pericardial sac.
What kind of blood is located on the left side of the heart, and is high on oxygen (O2) and low in carbon dioxide (CO2).
What kind of blood is located on the right side of the heart, and is low on oxygen (O2) and high in carbon dioxide (CO2).
components found in the right atrium
Pectinate muslces, fossa ovalis, foramen ovale, openings to the superior and inferior vena cava are also visible.
components found in the left atrium
Pectinate muscles, openings of the pulmonary veins are also visible.
components found in the left ventricle
Trabeculae carnae, papillary muscles, chordae tendinaea, and the entrance the aorta.
Pericardial sac, fibrous pericardium, parietal layer of serous pericardium, visceral layer of serous pericardium
What are the layers of the pericardium?
Exterior structures of the heart.
Coronary sulcus, interventricular sulcus, anterior interventricular sulcus, posterior interventricular sulcus, right and left auricles, right and left coronary arteries, right marginal artery, posterior interventricular artery, circumflex artery and branch, and anterior interventricular artery.
Intercalated discs, desmosomes, gap junctions, sarclemma
Intercellular structures of myocardial cells.
1) Sinoatrial (SA) node, 2) Atrioventricular (AV) node, 3) Atrioventricular (AV) bundle, and 4) Purkinge fibers.
The electrical conduction system components and order they initiate and conduct electrical signals.
Speeding up and slowing of electrical current
The SA node fires first and the the Av node delays it to allow the atria to fully constrict, then the AV branches off and the Purkinje fibers fire the fastest so that the ventricles constrict at the same time.
Sound rarely heard in people younger than 30, turbulent sound generated by blood slamming against the vessels.
Central nervous system input to the heart
Main purpose is to slow the heart down. Does not initiate heart beat!
Relatively deep grove that separate the ventricles externally, extends around the circumference of the heart.
Groove located between the ventricles that extends inferiorly from the coronary sulcus toward the heart apex and delineates the superficial boundary between the right and left ventricles.
Outermost heart layer. Serious membrane composed of simple squamous epithelium and an underlying layer of areolar connective tissue.
Middle layer of the heart wall. Composed of cardiac muscle tissue and is the thickest of the three heart wall layers.
Covers the internal surface of the heart and the external surfaces of the heart valves. Composed of simple squamous epithelium called endothelium, and an underlying layer of areolar connective tissue.
Shunted blood from the right atrium to the left atrium, bypassing the lungs during fetal development.
Cone shaped muscular projections, used to anchor thin strands of collagen fibers called chordae tendineae.
when open cusps extend into the ventricles and allows blood to move from atrium to ventricle. With ventricular contraction blood forced superiorly causes it to close. Attached by chordae tendinae and papillary muscles.
Composed of 3 pocket like cusps, do not have papillary muscles or chrdae tendinae. Opens when ventricles contract and closes when ventricles relax.
Unique structures found at cell junctions. Link cardiac muscle cells together both mechanically and electrically.
Protein filaments that anchor into a protein plaque located on the internal surface of the sarcolemma. They act as mechanical junctions to prevent muscle cells from pulling apart.
Protein pores between the sarcolemma of adjacent cardiac muscle cells. They provide a low resistance pathway for the flow of ions between the cardiac cells.
Supports the heart internally and is composed of dense irregular tissue. Provides structural support, anchors heart valves, provides framework for attachment of cardiac muscle tissue, and acts as an electric insulator.
Right and left coronary arteries
These 2 arteries travel within the coronary sulcus of the heart to supply the heart wall. First and only branches of the ascending aorta.
Right marginal artery
Supplies the right border of the heart, branches off the right coronary artery.
Posterior interventricular artery
Supplies the posterior surface of both the left and right ventricles, branches off of the right coronary artery.
Anterior interventricular artery
Supplies the anterior surface of both ventricles and most of the interventricular septum, branches off of the left coronary artery.
Functional end arteries
Arteries that have anastomoses but are too tiny to shunt sufficient blood from one artery to the other.
Great cardiac vein
Vein located within the anterior interventricular sulcus, positioned alongside the anterior interventricular artery.
Middle cardiac vein
Vein located within the posterior interventricular sulcus, positioned alongside the posterior interventricular artery.
A large vein that lies within the posterior aspect of the coronary sulcus, collects venous blood and drains deoxygenated blood from the heart wall directly into the right atrium of the heart.
Specialized cardiac muscle cells found within the heart, do not contract but initiate and conduct electrical signals.
Atrioventricular AV node
Located in the floor of the right atrium between the right AV valve and the opening of the coronary sinus.
Atrioventricular AV bundle
Extends from the AV node into and through the interventricular septum. Divides into left and right.
Extends from left and right bundles from the apex of the heart and then continue through the walls of the ventricles.
Within the medulla oblongata, houses parasympathetic and sympathetic pathways that extend from here. does not initiate heartbeat but modifies it.
Comes from the caridoinhibitory center via the left and right vagus nerve (CN10), decrease heart rate.
Comes for the cardioacceleratory center, increases dilation of vessels, speeds up heart rate.
Reflex that protects the heart from overfilling, initiated when baroreceptors in the atrial walls are stimulated by an increase in venous return.
Pacemaker cells in the SA node that initiate a heartbeat. Generate an action potential and thus they have properties similar to neurons.
Capability to depolarize and fire an action potential spontaneously without any external influence.
Time between depolarization and repolarization when the muscle cannot be restimulated to contract.
Reflects electrical changes of atrial depolarization that originates in the SA node, on a EKG.
Represents the electrical changes associated with ventricular depolarization, the atria are simultaneously repolarizing, on the EKG.
Associated with the atrial plateau at the sarcolemma when the cardiac muscle cells within the atria are contracting on the EKG.
Ventricular plateau when the cardiac muscle cells with the ventricles are contracting on a EKG.
Represents the period of time from the beginning of the P wave (atrial depolarization) to the beginning of the QRS complex (ventricular depolarization) on a EKG.
Represents the time from the beginning of the QRS (venticular depolarization) and the end of the T wave (ventricular repolarization) on a EKG.
The inclusive changes within the heart from the initiation of one heartbeat to the start of the next.
The amount of blood that is pumped by a single ventricle (left or right) in 1 minute, typically expressed as liters per minute.
Alter activity of nodal cells either directly or indirectly by acting on nerves that innervate the SA node or the AV node.
Positive chonotropic agents
Cause an increase in heart rate and include sympathetic nerve stimulation and certain types of hormonal stimulation,
The stretch of the heart wall due to the load to which a cardiac muscle is subjected before shortening.
Frank Starling Law
Law that states that as the volume of the blood entering the heart increases, there is greater stretch of the heart wall.
The resistance in arteries to the ejection of blood by the ventricles, and it represents the pressure that must be exceeded before blood is ejected from the chamber.