Heart Anatomy and Cardiac Circuit

pulmonary circuit

starts: right ventricle

ends: left

pumps oxygen poor blood to the lungs

systemic circuit

starts: left ventricle

ends: right atrium

pumps oxygen rich blood into the systemic tissues and removes CO2 waste

sulci

grooves separating chambers

contain important vessels that provide oxygen and nutrients to heart tissue and drains waste products and oxygen poor blood from heart tissue

coronary sulcus

yellow; atrioventricular sulcus

border between atria and ventricles

contain: coronary arteries and sinus

anterior interventricular sulcus

green; border between right and left ventricles on anterior surface

contain: anterior interventricular artery and great cardiac vein

posterior interventricular sulcus

white; border between right and left ventricles on posterior surface

contain: posterior interventricular artery and middle cardiac vein

coronary arteries

supply blood to heart

starts at base of aorta and encircle heart in atrioventricular groove

right coronary artery

feeds right atrium, majority of right ventricle, portion of left ventricle, portion of interventricular septum

splits into:

• posterior interventricular artery

• marginal arteries

left coronary artery

feeds left atrium, majority of left ventricle, portion of right ventricle, portion of interventricular septum

splits into:

• anterior interventricular artery

• circumflex artery

coronary veins

return blood to the circulation; empty into the coronary sinus and blood flows directly into the right atrium from the coronary sinus (via opening of coronary sinus)

middle cardiac vein

returns blood from posterior portion of heart (runs along posterior interventricular artery)

small cardiac vein

returns blood from right side of heart (runs along marginal artery)

great cardiac vein

returns blood from anterior portion of heart (runs along anterior interventricular artery)

widow maker

massive heart attack caused by blockage of the anterior interventricular artery

reperfusion

restoring blood flow to an organ from which it has been blocked

myocardial ischemia

blood flow to the heart is reduced from blockage of the coronary arteries

transient flow interruption = mid/mild occlusion

• angina pectoris- pain due to spasm of cardiac muscle

if flow blockage is complete and prolonged

• myocardial infarction

• death of tissue

• dead muscle can’t be replaced

• occlusion of R or L main coronary artery can mean instant death

fibrous skeleton

anchors heart valves

pectinate muscles

muscle arranged into ridges on anterior surfaces and in auricles

interatrial septum

separate left and right atria

internal structures of ventricles

conus arteriosus, trabeculae carneae, papillary muscles, chordae tendineae, interventricular septum

conus arteriosus

smooth region that directs blood out of right ventricle; no trabeculae

trabeculae carneae

ridges of myocardium in ventricle; prevent walls of ventricles from sticking together during contraction

papillary muscles

thickened extensions of trabeculae; numbers correcpond to leaflets in valve (each attaches to multiple leaflets)

chordae tendineae

attach valves to papillary muscles; prevent backflow of blood into atria when ventricles contract

what drives movement of blood

cardiac muscle contractions and pressure changes; valves prevent backflow

atrioventricular valves

open when ventricle is filling; close when ventricle is pushing blood out to body; moves from atria to valve

semilunar valves

open when ventricle is emptying; close when ventricle is filling; from ventricle to artery (push blood out of heart)

progression of blood flow through the heart

1. SVC + IVC → right atrium

2. right atrium → right ventricle (right atrioventricular valve)

3. right ventricle → pulmonary circuit (pulmonary trunk, pulmonary semilunar valve)

4. pulmonary veins → left atrium

5. left atrium → left ventricle (left atrioventricular valve)

6. left ventricle → systemic circuit (aorta, aortic semilunar valve)

heart murmur

occurs when a valve is slightly leaky; some blood regurgitates backward creating turbulence; some are innocent

diastolic murmur

heart is filling with blood (relaxed); right atrium

systolic murmur

heart is emptying; atrioventricular valve closed

continuous murmur

throughout the heartbeat; all the time

prolapse

occurs when valve is very leaky due to improper closure; blood regurgitates leading to congestion in circuit

stenosis

difficult to open a valve usually due to scar tissue formation

• valve tissue becomes stiff and is constricted by scar tissue making valve hard to open

• may lead to backup in circuit

• produce whistling sound