Heart's Function:
Pump enough blood to meet the body's metabolic needs.
Heart has three layers name them:
Epicardium- outermost layer- ehre coronary arteries lie.
Myocardium-middle muscular layer- does the work of contracting- damaged during a heart attack.
Endocardium- innermost layer-watertight-lines the chambers and forms the hurt valves. The conduction sy
Heart has four chambers name them:
Right Atrium- receiving chamber for deoxygenated blood returning to heart from body.
Right Ventricle-pumps deoxygenated blood to lungs so it can be oxygenated.
Left Atrium-revieving chamber for oxygenated blood coming from lungs.
Left ventricle-major pump
Interventriular septum
band of tissue that separates right and left ventricles.
Intreratrial septum
separates right and left atria.
Four heart valves
job is to proven back flow of blood. Valves open in direction of blood flow-AV valves open downward, semilunar valves open upward.
Pulmonic valve
semilunar valve between right ventricle and pulmonary artery.
Aortic Valve
semilunar valve between left ventricle and aorta.
Tricuspid valve
AV valve between right atrium and right ventricle.
Mitral valve
AV valve between left atrium and left ventricle.
Superior vena cava
(SVC)-large vein-returns deoxygenated blood from upper body to the heart.
Inferior vena cava
(IVC)-large vein-returns deoxygenated blood from lower body to the heart.
Pulmonary artery
(PA)-takes deoxygenated blood from right ventricle to lungs-only artery in the body that carries deoxygenated blood.
Pulmonary veins
takes oxygenated blood from lungs to left atrium-only veins that carries oxygenated blood.
Aorta
(Ao)-main artery of the body-carries oxygenated blood to the body.
Blood flow through the heart
Superior/inferior vena cava-right atrium-tricuspid valve-right ventricle-pulmonic valve-pulmonary artery-lungs-pulmonary veins-left atrium-mitral valve-left ventricle-aortic valve-aorta-body.
Cardiac Cycle
mechanical events that occur to pump blood.
Diastole
ventricles relax and fill with blood
Systole
ventricles contract and expel blood
Diastole/Rapid filling
Atria full of blood, ventricles empty. Pressure differential causes AV valves to pop open-blood rapidly fills ventricles.
Diastole/Diastasis
Pressures equalize between atria and ventricles-flow into ventricles slows.
Diastole/Atrial Kick
Atria contracts to squeeze remainder of blood into the ventricles.
Systole/Isovolumetic contraction
Ventricles contracting,no blood flow occurring because the aortic and pulmonic valves are still closed. Huge expenditure of myocardial oxygen consumption.
Systole/Ventricular ejection
valves open-blood pours out of ventricles into pulmonary artery and aorta.
Systole/Protodiasole
Pressures equalize between ventricles and pulmonary artery and aorta-blood flows slows.
Systole/Isovolumetric relaxation
ventricles relax-pulmonic and aortic valves close.
Blood flow through the systemic circulation
Aorta-arteries-arterioles-capillaries-venules-veins- vena cava
Coronary arteries
Supply blood flow to myocardium.
Coronary artery/Left anterior descending
(LAD)-branch off left main coronary artery-provides blood flow to anterior wall of left ventricle.
Coronary artery/Circumflex
Also a branch off the left main coronary artery-provides blood flow to lateral wall of the left ventricle.
Coronary artery/Right coronary artery
Provides blood flow to right ventricle and interior wall of left ventricle.
Contractile cells
Cause the heart to contract, resulting in a heartbeat
Conduction system cells
create and conduct electrical impulses to tell the heart when to beat.
Sympathetic
(SNS)-Mediated by hormone norepinephrine- causes fight-or-flight response- speeds up heart rate, increases blood pressure, dilates pupils, and slows down digestion.
Parasympathetic
(PNS)- Mediated by acetylcholine-causes rest-and-digest response. Slows heart rate, lowers blood pressure, enhances digestion.