CIRCULATORY SYSTEM AND THE HEART
Heart Anatomy 4 chambers of the heart
Right and Left Atrium (enters heart) Right and Left Ventricles (leaves the heart)
2 atria contract simultaneously and shortly after 2 ventricles contract
REAL THING!!! Minus the Pericardium
Posterior Surface View
Frontal section (interior chambers)
Heart ValvesKnow this and not what is in your text!
Atrioventricular valves Tricuspid valve (Right A.V. valve) Bicuspid valve (Left A.V. valve)
ALSO Mitral valve
Semilumar valves Aortic semilunar valve (aorta) Pulmonary semilunar valve (pulmonary trunk)
Heart Valves
Superior/ Inferior Vena Cava
Right Atrium
Right Ventricle
Pulmonary Artery
Lungs
Pulmonary Veins
Left Atrium
Left Ventricle
Aorta
Body Tissue
Sinoatrial (S-A) Node (Pacemaker)
Specialized muscle tissue, located in the wall of the R. atrium, stimulates the muscle fibers to contract and relax rhythmically
Atrioventricular (AV) Node As atria contract, impulse reaches A-V
node Transmits electrical impulse over the
walls of the ventricles to start ventricular contraction
Cardiac Intrinsic Conduction System
(ECG) Electrocardiogram Records electrical activity P = atrial depolarization QRS = ventricular depolarization T = ventricular repolarization
When does the atrial repolarization occur?
ELECTROCARDIOGRAPH (ECG)
Chemical Regulators Noradrenaline – makes the S-A node fire
more rapidly (during exercise or “fight or flight”)
Acetylcholine – slows the firing of the S-A node
Cardiac output and Fitness Cardiac output – amount of blood
pumped by the heart Affected by:
1) Heart Rate 2) Stroke volume – amount of blood forced
out of heart with each heart beat.Cardiac output = stroke volume X heart rate
Homework Page 311 # 1, 3, 7
Quiz tomorrow
Anterior Aspect (front)
Heart Anatomy cont’d Which heart chamber has the thickest
walls? Left Ventricle What is the significance of this structural
difference? Pumps blood to entire body (systematic
circuit)