Post on 24-Feb-2016
description
The Heart
Ch. 20
Circulation•Pulmonary
▫Eliminates carbon dioxide and oxygenates blood
▫Involves lungs•Systemic
▫Delivers blood to body cells and carries waste away
▫Involves the body
Heart• About the size of your fist• Rests on the diaphragm,
near the midline of the thoracic cavity▫ Surrounded by
pericardium (protects)• Lies in the mediastinum,
2/3 is to the left of the midline
Pericardium•Surround
s heart
Pericardium• 3 layers
▫Epicardium – external layer Thin, transparent layer;
makes heart smooth and slippery
▫Myocardium – middle layer Cardiac muscle, makes up
bulk of heart Responsible for pumping
action▫Endocardium – inner layer
Thin tissue, covers valves
Chambers of the Heart• Atria – superior chambers (receive blood from veins)• Ventricles – inferior chambers (pump blood out of
arteries)• Septum – separates right and left sides• Auricle – wrinkled, pouch-like structure on each atrium
▫ Increases volume of blood each atrium can hold• Sulci – grooves on surface of heart; contain blood
vessels and fat▫ Separates two chambers▫ Coronary sulcus – divides atria from ventricles▫ Anterior/posterior interventricular sulcus – divides
ventricles
Heart•Double
pump &double circuit
Heart Valves• Valves – allow one way flow of blood• 4 total valves• 2 atrioventricular (AV) valves
▫Left AV valve (bicuspid or mitral valve) – between LA and LV
▫Right AV valve (tricuspid valve) – between RA and RV• 2 semilunar valves
▫Aortic semilunar (aortic valve) – between LV and aorta
▫Pulmonary semilunar (pulmonary) – between RV and pulmonary artery
Heart Valves
Path of Blood Flow•From the body into heart through vena cava•Into RA•Into RV•Out to lungs through pulmonary arteries•Into heart from lungs through pulmonary
veins•Into LA•Into LV•Out to body through aorta
Path of Blood Flow
Path of Blood Flow
Name the Valves
Heart Actions•Cardiac Cycle – one complete heart beat•Contraction of heart chamber – systole•Relaxation of heart chamber – diastole
Contraction Cycle
Valve Control•Cusps (flaps) of
bicuspid and tricuspid valves are anchored to walls of ventricles by “cords” (heart strings) – chordae tendineae
•This prevents valves from being pushed up into the atria during ventricular systole
Heart Sounds•Lub-dup – opening and closing of the
valves•Sound byte
http://www.ilovewavs.com/Effects/People/Sound%20Effect%20-%20Heart%20Beat%2001.wav
Cardiac Conduction•SA node•Right and left
bundle branches
•AV node•AV bundle•Perkinje fibers
Cardiac Conduction
Name the Parts
Review•What are the two circulatory systems? What
do they do?•Where is the heart located?•What is the pericardium? What three layers
does it contain?•Describe the main structures of the heart.•Describe the valves of the heart.•What is the cardiac cycle?•What are the heart strings? What do they do?•Describe cardiac conduction.