Chapter 1 - The Heart & Its Functions Flashcards
The Heart [thoracic cavity]
top = base / bottom = apex
Muscle that accepts DEOXYGENATED blood from the body, pumps it to the lungs where it OXYGENATED, and then pumps the oxygenated blood to all parts of the body.
Five Great Vessels
1) superior vena cava (returns blood from upper torso & head to right atrium)
2) inferior vena cava (returns blood from lower extremities of body)
3) pulmonary arteries
4) pulmonary veins
5) aorta
Right side of the heart is a _______ system that pumps ________ to the lungs.
low-pressure; deoxygenated
Left side of the heart is a _______ system that pumps ________ to the systemic circulation.
high-pressure; oxygenated
Four Chambers of the Heart
Upper chambers: atria (separated by the interatrial septum)
Lower chambers: ventricles (separated by the interventricular septum)
Four Valves
Two sets of atrioventricular valves (AV valves)
1) tricuspid valve (b/w RA & RV)
2) mitral valve (b/w LA & LV)
Two sets of semilunar valves (prevent backflow of blood into the ventricles)
1) pulmonic valve (b/w RV & pulmonary artery)
2) aortic valve (b/w LV & trunk of aorta)
Chordae Tendinae (“heart strings”)
Thin strands of fibrous, connective tissue which are attached to papillary muscles in the wall of the ventricles; work together to prevent cusps from fluttering back into atrium and disrupting blood flow through the heart.
Epicardium/Visceral Pericardium
External layer that includes: blood capillaries, lymph capillaries, nerve fibres, & fat.
Myocardium (muscle)
Thickest layer of the heart; responsible for the heart’s ability to contract (composed of cardiac muscle cells).
Endocardium
Innermost layer lining the heart’s chambers, valves, chordae tendineae, & papillary muscles (contains the cardiac conduction system).
BLOOD FLOW THROUGH THE HEART
superior/inferior vena cava (deoxygenated) –> right atrium –> tricuspid valve (AV valve) –> right ventricle –> pulmonary valve (SLV) –> pulmonary artery —> LUNGS (oxygenated) –> pulmonary vein –> left atrium –> mitral valve (AVV) –> left ventricle –> aortic valve (SLV) –> aorta (descending aorta) –> rest of the body
Systole
Phase of the cardiac cycle where the atria & ventricles contract.
Diastole
Atria & ventricles relax between contractions & blood enters these chambers.
Atrial Diastole
Atria are relaxed, blood flows into them from body & lungs.
Atrial Systole
Atria filled & atrial pressure higher than ventricle, tricuspid valves open –> atria contract & ventricles fill. (also the beginning of ventricular diastole)
Ventricular Diastole
Ventricles fill with blood until pressure of the atria & ventricles are equal (when equal av valves close)
Ventricular Systole
Ventricles contract & increase pressure in ventricles forcing aortic & pulmonary valves to open –> blood propelled through systemic & pulmonary circulation
Coronary Arteries
Supply the heart with blood rich in oxygen & nutrients
Right Coronary Artery
Supplies blood to the right atrium, right ventricle, & part of the left ventricle. RCA also supplies blood to the Bundle of His & the AV node. (In 50% of population, this artery supplies blood to the sinoatrial node)
Left Anterior Descending Artery (LAD)
LAD runs down the surface of the left ventricle towards the apex & supplies blood to the anterior wall of the left ventricle, the interventricular septum, the right bundle branch, & the left anterior fascicles of the left bundle branch.
Circumflex Artery
Supplies blood to the lateral (side) wall of the left ventricle, left atrium, & left posterior fascicle of the left bundle branch.
