Anatomy Exam 2

Pericardium

Double-layered fibro-serous sac enclosing the heart and roots of the great vessels; supplied by the pericardiocophrenic branch of the internal thoracic artery and the pericardial artery from the aorta; innervated by the phrenic nerve

Pericardiocophrenic artery

Branch of the internal thoracic artery that supplies the pericardium

Pericardial artery

Branch of the thoracic aorta that supplies the pericardium

Fibrous pericardium

Embryologically derived from the pleuro-pericardial membranes; fused to central tendon of the diaphragm; inelastic; protects from overfilling of the heart

Parietal serous pericardium

Embryologically derived from mesothelium; fused to the internal surface of the fibrous pericardium

Visceral serous pericardium

Embryologically derived from the mesothelium; fused to the epicardium

Pericardial cavity

Potential space between parietal and visceral layers; filled with some fluid

Oblique pericardial sinus

Reflection of visceral and parietal serous pericardial layers that is the “cul de sac” behind the veins/left atrium

Transverse pericardial sinus

Reflection of visceral and parietal serous pericardial layers that is between arteries (outflow) and veins (inflow)

Pericardiocentesis

Removes excess fluid from pericardial cavity

Pulmonary circulation

Controlled by the right side of the heart; deoxygenated blood enters the right atrium via the vena cavae; right ventricle relaxes, drawing blood into it; right ventricle contracts, pumping blood through the pulmonary trunk and into pulmonary arteries which go to the lungs for oxygenation

Systemic circulation

Controlled by the left side of the heart; oxygenated blood returns from the lungs to the heart via pulmonary veins and enters the left atrium; left ventricle relaxes, drawing blood into it; left ventricle contracts, pumping blood through the aorta to the rest of the body; also pumps to the coronary system which serves the heart tissue itself

Right atrium

Receives deoxygenated blood mostly from the superior/inferior vena cava, coronary sinus, and anterior cardiac veins; auricle on the outside; has fossa ovalis, sinus venarum, and crista terminalis

Crista terminalis

Structure of the right atrium that separates the rough walls from the smooth walls; ridge between the pectinate muscle and the sinus venarum

Sinus venarum

Smooth, posterior wall of the right atrium; embryologically from the right horn of the sinus venosus

Fossa ovalis

Remnant of the embryological foramen ovale, which allowed oxygenated blood to bypass the lungs by shunting between atria

Pectinate muscles

Rough, anterior wall of the atria of the heart; embryologically derived from the primitive atrium

Interatrial septum

Divides right and left atria

Right ventricle

Receives deoxygenated blood from the right atrium via the tricuspid (atrioventricular) valve; sends blood to the pulmonary trunk via the pulmonary (right semilunar) valve; has chordae tendineae, trabeculae carneae, papillary muscles, septomarginal trabecula, and conus arteriosus

Trabeculae carneae

Irregular, muscular ridges projecting from the inner walls of the heart’s ventricles; embryologically derived from primitive ventricle

Septomarginal trabecula (moderator band)

Band of cardiac muscle in the right ventricle that aids in coordinated contraction

Conus arteriosus

Smooth wall next to the outflow tract of the right ventricle; embryologically derived from the bulbus cordis

Interventricular septum

Divides right and left ventricles

Left atrium

Receives oxygenated blood from pulmonary veins; auricle on outside

Left ventricle

Receives oxygenated blood from the left atrium via the tricuspid (mitral) valve; sends blood to the rest of the body via the aortic (left semilunar) valve; has trabeculae carneae, papillary muscles, and aortic vestibule

Aortic vestibule

Smooth outflow portion of the left ventricle; embryologically derived from the bulbus cordis

Cardiac skeleton

Fibrocartilaginous tissue that divides the atria from ventricles, provides barriers between them for conductive system, and provides attachment for heart valves and myocardium; has tendon of conus arteriosus, left/right fibrous trigones, and membranous portions of the interventricular septa

Tendon of conus arteriosus

Part of the cardiac skeleton that connects the back part of the right ventricle’s outflow tract to the root of the aorta and its fibrous ring

Left fibrous trigone

Triangle of the cardiac skeleton formed by connections from the mitral valve to the aortic semilunar valve

Right fibrous trigone

Triangle of the cardiac skeleton formed by connections from both atrioventricular valves to the aortic semilunar valve

Right coronary artery

Heart blood supply originating from the ascending aorta; supplies the SA node primarily and the AV node; has marginal branch, posterior interventricular branch, and SA nodal branch in 60% of people

Left coronary artery

Heart blood supply originating from the ascending aorta; has circumflex branch which may have SA nodal branch in 40% of people; has anterior interventricular branch which gives off diagonal branch

Coronary sinus

Main drainage vein of heart; empties into right atrium; lies in coronary sulcus; receives blood from great, middle, and small cardiac veins

Great cardiac vein

Runs with anterior interventricular artery; drains into coronary sinus

Middle cardiac vein

Runs with posterior interventricular artery; drains into coronary sinus

Small cardiac vein

Runs with right marginal artery; drains into coronary sinus

Anterior cardiac veins

Drain directly into the right atrium instead of the coronary sinus

Base of heart

Primarily formed by left atrium against thoracic vertebrae

Apex of heart

Primarily formed by left ventricle protruding in left 5th intercostal space

Sternocostal (anterior) surface of heart

Formed by the right ventricle

Diaphragmatic (inferior) surface of heart

Formed by both ventricles, but mostly the left

Pulmonary (left) surface of the heart

Formed by the left ventricle; occupies cardiac notch

Right border of the heart

Small and slightly convex; primarily formed by the right atrium; located from the right 3rd costal cartilage to the right 6th costal cartilage

Inferior border of the heart

Formed by the right ventricle and the apex of the left ventricle; located from the right 6th costal cartilage to the left 5th intercostal space

Left border of the heart

Formed by the left ventricle and left auricle; located from the left 5th intercostal space to the left 2nd costal cartilage

Superior border of the heart

Formed by the right and left atrial auricles; located from the left 2nd costal cartilage to the right 3rd intercostal cartilage

Heart sounds

Result of blood flow turbulence after valve closure

“Lub” heart sound

First sound of auscultation; formed by the turbulence when the atrioventricular valves close

“Dub” heart sound

Second sound of auscultation; formed by the turbulence when the semilunar valves close

Cardiac plexus

Main innervation of heart; mix of afferent-visceral, sympathetic, and parasympathetic fibers

Sympathetic heart innervation

Presynaptic fibers from T1-T4; increase heart rate, conduction, and coronary blood flow; visceral afferents follow along spinal levels, possibly resulting in referred pain

Parasympathetic heart innervation

Vagus nerve; decreases heart rate and coronary blood flow

Sinoatrial node

Pacemaker of the heart; initiates impulse for contraction (70-80/min); located at the junction of superior vena cava and right atrium; blood supply from right coronary artery in 60% of people (left in 40%)

Atrioventricular node

Can initiate impulses if required, but only 40-60/min; located in posteroinferior region of interatrial septum, near the coronary sinus; collects impulses from atria and distributes to ventricles; blood supply from right coronary artery in 80% of people

Atrioventricular common bundle (bundle of His)

Can initiate impulses if required, but only 20-40/min; located within interventricular septum to the ventricular myocardium; divides into right and left branches; main blood supply from left coronary artery

Purkinje fibers

Sometimes referred to as subendocardial; branches from right and left atrioventricular bundles; located within the ventricular walls; blood supply is dependent on exact locations