Practical 2, The Heart

mediastinum

the heart is located in the _____________, the central portion of the thoracic cavity

tissues of the body and to and from the lungs

the heart is a two sided pump simultaneously responsible for pushing blood to and from the ________________________

endocardium, myocardium, and epicardium

three layers of the heart wall

endocardium

innermost layer of heart walll

endocardium

lines the internal walls of the heart

myocardium

middle, thickest layer of heart wall

myocardium

composed primarily of cardiac muscle

epicardium

also known as the visceral pericardium

epicardium

outermost layer of heart wall

epicardium

composed of connective tissue and simple squamous epithelium

parietal pericardium

forms a sac of strong fibrous tissue around the heart

visceral pericardium

simple squamous epithelium on the outer surface of the heart (epicardium)

apex

inferior, pointed end

base

broad, superior portion of the heart; location of the great vessels

right auricle

flap-like structure on top of the right atrium; allows for expansion of the right atrium when it fills with blood

left auricle

flap-like structure on top of the left atrium; allows for expansion of the left atrium when it fills with blood

coronary (atrioventricular) sulcus

groove on the surface between the atria and ventricles; location of the coronary arteries

anterior interventricular sulcus

groove on the anterior surface between the ventricles; location of the anterior interventricular artery and the great cardiac vein

posterior interventricular sulcus

groove on the posterior surface between the ventricles; location of the posterior interventricular artery and the middle cardiac vein

ligamentum arteriosum

small fibrous cord connecting the pulmonary trunk to the aorta; remnant of the fetal ductus arteriosus

superior vena cava

delivers systemic blood from structures superior to the heart and right atrium

inferior vena cava

delivers systemic blood from structures inferior to the heart and right atrium

pulmonary trunk

carries blood from the rught ventricle to the pulmonary arteries

pulmonary arteries

carries blood from the pulmonary trunk to the pulmonary capillaries

pulmonary veins

delivers oxygenated blood from the lungs to the left atrium

aorta

carries blood from left ventricle to the systemic capillaries in the body

right atrium

heart chamber that receives deoxygenated blood from the systemic circuit

left atrium

heart chamber that receives oxygenated blood from the pulmonary circuit

interatrial septum

dividing wall between the two atria

fossa ovalis

remnant of the foramen ovale, a fetal structure that allows blood to bypass the pulmonary circuit

pectinate muscle

prominent ridges lining the surface of the atria

right ventricle

heart chamber that receives deoxygenated blood from the right atrium

left ventricle

heart chamber that receives oxygenated blood from the left atrium

interventricular septum

dividing wall between two ventricles

trabeculae carnae

prominent ridges lining the surface of the ventricles

moderator band

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

tricuspid valve

three-cusp valve between the right atrium and right ventricle (right AV valve)

bicuspid valve

two-cusp valve between the left atrium and left ventricle (left AV valve, mitral valve)

chordae tendineae

long fibrous cords of connective tissue that connect the papillary muscles to the AV valves; prevent AV valve prolaps during ventricular systole

papillary muscles

projections of cardiac muscle within the ventricles; attached to the chordae tendinae, which contract to prevent AV valve prolapse

pulmonary valve (right semilunar)

three-cusp valve between the right ventricle and pulmonary trunk

aortic valve (left semilunar)

three-cusp valve between the left ventricle and aorta

ligamentum anteriosum

fibrous cord connecting the pulmonary trunk to the aorta; remnant of fetal structure

right coronary artery

branches off the aorta and extends laterally around the posterior side of the heart; delivers blood to the right marginal artery

left coronary artery

branches off the aorta and extends inferiorly towards the left ventricle; branches to form the circumflex and anterior interventricular arteries

anterior interventricular artery

branch from the left coronary artery; sits in the anterior interventricular sulcus; supplies blood to the anterior sides of both ventricles (widow maker)

circumflex artery

major branch of the left coronary artery; extends laterally around the left side of the heart to supply blood to the left atrium and posterior side of the left ventricle

posterior interventricular artery

branch from the right coronary artery; sits in the posterior interventricular sulcus; supplies blood to the posterior, middle, and right sides of the myocardium

right marginal artery

branches off the right coronary artery; supplies blood to the right lateral side of the heart

left marginal artery

Branches off the circumflex artery; supplies blood to the left lateral side of the heart.

anterior cardiac veins

small veins that drain the anterior surface of the right ventricle; empties blood directly into the right atrium

small cardiac vein

drains the right lateral side of the heart; empties into the coronary sinus

great cardiac vein

runs parallel to the anterior interventricular artery; drains blood from the anterior surface of the heart; travels superiorly before following the coronary sulcus laterally around the heart; empties into the coronary sinus

posterior cardiac vein

drains the left lateral side of the heart; empties into the coronary sinus

middle cardiac vein

runs parallel to the posterior interventricular artery; drains blood from the posterior surface of the heart; empties into the coronary sinus

coronary sinus

large horizontal vessel on the posterior side of the heart; collects blood from several cardiac veins; drains into the right atrium

stimulation

your heart is unique in that it requires no ___________ from nerves in order to contract

oxygen

if removed from your body, the heart will continue to beat until it runs out of ____________

autorhythmic cells

internal stimulation cells, non contractile

autorhythmic cells

collectively called the conduction system of the heart

electrical currents

the conduction of action potentials throughout the heart walls can be detected as ____________________.

electrocardiogram

An instrument called an electrocardiograph records these electrical currents on a chart called an ______________________

sinoatrial (SA) node

true "pacemaker" of the heart, located in the wall of the right atrium

atrioventricular (AV) node

located between the right atrium and right ventricle; receives impulses from the SA node; sends impulses to the AV bundles, links the atria to the ventricles electrically

atrioventricular bundle

receives impulses from the AV node and sends them to the bundle branches (Bundle of His)

bundle branches

two pathways that arise from the AV bundle and conduct impulses through the interventricular septum to the Purkinje fibers

purkinje fibers

myoconduction fibers found in the apex of the heart; transmit impulses from the bundle branches through the ventricle walls

P Wave

atrial depolarization initiated by the SA node

QRS Complex

ventricular depolarization and atrial repolarization

T Wave

ventricular repolarization

P-R interval

time it takes the electrical impulse to travel from the SA node through the AV node and enter the ventricles

S-T segment

represents the duration of ventricular depolarization

close

as blood flows, the valves that separate the chambers and the ventricles from two of the great vessels __________ in response to pressure generated by the contraction of the heart chambers

lubb-dupp

can be heard with a stethoscope

both AV valves shutting

lubb sound caused by ________________ during ventricular systole

both semi-lunar valves shutting

dupp sound caused by __________________ during ventricular diastole

auscultation areas

where the heart sounds can be heard

atrial septal defect

Most commonly seen as a congenital defect in infants where the foramen ovale does not close properly.

atrial septal defect

Symptoms include: dyspnea, frequent respiratory infections in children, heart palpitations, and shortness of breath after light activity

angina pectoris

results from poor blood flow (usually due to atherosclerosis) in the coronary arteries

angina pectoris

the resulting lack of oxygen to the myocardium causes the following symptoms: chest pain (slightly left sternum), tightness that spreads down left arm, or severe indigestion or heartburn

myocardial infarction (MI)

caused by a clogged vessel, which leads to death or damage of the myocardium

myocardial infarction (MI)

symptoms are similar to Angina pectoris, just prolonged

arrhythmias

defects in the conduction system causing irregular heart rhythms.

arrhythmias

if not corrected, this can lead to uncoordinated atrial and ventricular contractions

fibrillation

rapid and irregular out of phase contractions where control of the heart rhythm is not in the SA node

fibrillation

during this, blood does not move from the heart

defibrillation

_____________________ must occur to prevent brain death due to lack of oxygen

heart block

most commonly caused by an interference of the impulse transmission from the atria to the ventricles through the AV node.

partial heart block

_______________________ is where only some of the atrial impulses reach the ventricles.

total heart block

_________________________ is where no impulses get through and the ventricles beat at their own rate, which is much too slow to maintain circulation.

artificial pacemakers

both total and partial heart blocks require __________________________ that recouple the atria to the ventricles

heart murmur

abnormal sound that can be detected using a stethoscope, not always fatal and not a defect

heart murmur

allows small amounts of blood or regurgitation (backflow) into the atria.