exam 2 terms: the heart

mediastinum

area within the thoracic cavity where the heart is located

apex

the inferior, pointed end of the heart

base

the superior, rounded end of the heart where the great vessels attach

endocardium

innermost layer of the heart wall composed of simple squamous epithelium

myocardium

the middle layer of the heart wall composed of cardiac muscle

epicardium

the outermost layer of the heart wall. synonymous with the visceral pericardium

annulus fibrosus (fibrous skeleton)

the fibrous connective tissue that supports the cardiac muscle and valves. separates the chambers electrically

atria

the 2 upper chambers of the heart (receiving chambers)

ventricles

the 2 lower chambers of the heart (discharging chambers)

fibrous pericardium

the outermost layer of the sac that surrounds the heart. anchors the heart

serous pericardium

the serous membrane that forms the sac around the heart. has a visceral and parietal layer

interatrial septum

the wall that separates the atria

interventricular septum

the wall that separates the ventricles

tricuspid valve

prevents back flow of blood from the right ventricle to the right atrium

mitral/bicuspid valve

prevents the back flow of blood from the left ventricle to the left atrium

fossa ovalis

depression in the interatrial septum that is a remnant of a hole in the fetal heart

trabeculae carne

the irregular ridges within the myocardium of the ventricles

papillary muscles

projections of muscle that the chord tendineae attach to

chordae tendineae

fibrous chords that extend off the flaps of the cuspid valves to attach to the flaps of the heart wall

aortic semilunar valve

prevents the back flow of blood form the aorta to the LEFT ventricle

pulmonary semilunar valve

prevents the back flow of blood from the pulmonary trunk to the RIGHT ventricle

superior vena cava

returns deoxygenated blood to the right atrium from structures ABOVE the armpits

inferior vena cava

returns deoxygenated blood to the right atrium from structures BELOW the armpits

pulmonary trunk

delivers deoxygenated blood from the right ventricle towards the lungs

Aorta

delivers oxygenated blood from the left ventricle towards the body

pulmonary veins

carry oxygenated blood from the lungs to the left atrium

coronary sinus

coronary veins on the posterior heart that collects blood from 3 coronary veins and drains to the right atrium

systole

the term for contraction of the heart muscle

diastole

the term for relaxation of the heart muscle

isovolumetric contraction phase

the brief moment at the beginning of ventricular systole when all valves are closed

isovolumetric relaxation phase

the brief moment at the beginning of ventricular diastole when all valves are closed

lub

heart sound made by closing of cuspid valves at beginning of ventricular systole

dup

heart sound made by closing of semilunar valves at the beginning of ventricular diastole

sinoatrial (SA) node

pacemaker of the heart. generates action potential that spreads throughout the atria

atrioventricular (AV) node

auto rhythmic cells that delay the impulse before relaying it to the Bundle of His

Bundle of His (AV bundle)

continuous with AV node and relay impulse through fibrous skeleton

bundle branches

autorhythmic cells that travel down the inter ventricular septum towards the apex

purkinje fibers

autorhythmic cells that branch and supply impulses to the papillary muscles and majority of ventricular wall

vagus nerves

parasympathetic nerve that supplies impulses to the SA node and AV node.

- releases ACH

cardiac nerves

sympathetic nerve that supplies impulse to the SA node, AV node and myocardium

- releases norepinephrine

chronotropic factor

factors that alter heart rate

inotropic factor

factors that alter strength of contraction of the heart

cardiac output

the amount of blood ejected from a ventricle in 1 minute

stroke volume

the amount of blood ejected from a ventricle in 1 contraction

ejection fraction

the %of the blood leaving the heart with each contraction

end diastolic volume (EDV)

the amount of blood in the ventricles at the end of diastole

end systolic volume (ESV)

the amount of blood in the ventricle at the end of systole

venous return

the amount of blood returning to the heart in the veins

preload

the amount of ventricular stretch before contraction

afterload

the pressure the heart has to work against to eject the blood

P wave

ECG deflection that represents atrial depolarization

QRS complex

ECG deflection that represents ventricular depolarization and atrial repolarization

T wave

ECG deflection that represents ventricular repolarization

heart block

a delay in conduction

bradycardia

a resting heart rate below 60 BPM

tachycardia

a heart rate above 100 BPM

fibrillation

an uncoordinated heart beat where patches of myocardium are beating independently

myocardial infarction (MI)

heart attack

beta blockers

medication for high blood pressure that binds beta receptors

calcium channel blockers

medication for high blood pressure that binds calcium channels