Download Introduction - Fullfrontalanatomy.com

Introduction
 The blood must stay in motion to maintain
homeostasis.
 The heart keeps blood moving.
 The volume of blood pumped by the heart can vary widely,
between 5 and 30 liters per minute.
An Overview of the Cardiovascular System
 The heart is a small organ; your heart is roughly the size of your clenched
fist.
 Two closed circuits:
 Pulmonary circuit carries carbon dioxide—rich blood from the heart to the lungs
and back
 Systemic circuit transports oxygen-rich blood from the heart to the rest of the body
and back
 The heart has four muscular chambers:
 Right and left atria collect blood returning to heart
 Right and left ventricles discharge blood into vessels to leave the heart
The Pericardium

The pericardium is the serous membrane lining the pericardial
cavity, which surrounds the heart
 Visceral pericardium (epicardium) covers the heart’s outer surface
 Parietal pericardium lines the inner surface of the pericardial sac
Structure of the Heart Wall
 Three distinct layers:
 Epicardium — covers the outside of the heart
 Myocardium — cardiac muscle
 Endocardium — lines the inside of the heart
Orientation and Superficial Anatomy of the Heart
 The heart lies slightly to the left of the midline.
 The heart sits at an oblique angle to the longitudinal axis of the
body.
 The heart is rotated slightly toward the left.
 The heart has external sulci that mark internal boundaries.
Internal Anatomy and Organization of the Heart
 Pulmonary circuit
 Right atrium
 Tricuspid valve
 Right ventricle
 Pulmonary valve
 Pulmonary trunk
 Systemic circuit
 Left atrium
 Mitral valve
 Left ventricle
 Aortic valve
 Aorta
Clinical Note
Internal Anatomy and Organization of the Heart
The Cardiac Cycle
 All of the electrical and mechanical events that take place
during one heart beat are referred to as one cardiac cycle.
 Systole — contraction
 Diastole — relaxation
The Electrocardiogram (ECG)
 The ECG is a recording of the electrical events in the heart.
 P wave — atrial depolarization
 QRS complex — ventricular depolarization
 T wave — ventricular repolarization