Chapter 13 – Cardiovascular System

13.1 Introduction

Systemic Circulation – delivers blood to all body cells and carries away waste
Pulmonary Circulation – eliminates carbon dioxide and oxygenates blood (lung pathway)

Arteries - carry blood away from the heart
Veins - return blood to the heart

13.2 Structure of the Heart

Heart Size – about 14 cm x 9 cm (the size of a fist)

Coverings of the heart

Pericardium encloses the heart (like a bag) (visceral, parietal)
Pericardial cavity – contains fluid for the heart to float in, reducing friction

Wall of the Heart

Epicardium – outer layer, reduces friction
Myocardium – middle layer, mostly cardiac muscle
Endocardium – inner layer, blood vessels and Purkinje fibers

13.3 Heart Chambers and Valves

Atria - top chambers

Ventricles - bottom chambers

Septum - divides left and right side

Atrioventricular Valve (AV) - these valves are located between the atrium and the ventricle

Tricuspid - right side AV

Bicuspid - left side AV, also called mitral valve

Superior Vena Cava - vessel the returns blood to the heart from the upper body

Inferior Vena Cava - vessel the returns blood to the heart from the lower body

Coronary Sinus - indentation on the front of the heart

Chordae tendinae / Papillary Muscles - muscles and tendons that hold the heart valves in place

Pulmonary Trunk/Arteries - large vessel that splits into the left and right pulmonary arteries, these are the only arteries that carry deoxygenated blood

Pulmonary valve - controls the flow of blood into the pulmonary trunk

Pulmonary Veins - returns oxygenated blood from the lungs

Aorta - large vessel that delivers blood to the body

Aortic Valve - controls the flow of blood into the aorta

Path of Blood Through the Heart

Quick Overview

1. Deoxygenated blood enters right atrium through the vena cava
2. Blood moves into the right ventricle
3. Blood goes out the pulmonary arteries and heads to the lungs
4. Blood returns from the lungs and enters the left atrium
5. Blood moves into the left ventricle
6. Oxygenated blood moves out of the left ventricle through the aorta and to the body

Labeling Practice - External Heart

heart