CHAPTER 18 exam prep.html - CHAPTER 18 The Cardiovascular...

This preview shows page 1 - 3 out of 7 pages.

CHAPTER 18The Cardiovascular System: HeartI. Anatomy of the HeartA. Physical Characteristics1. Situated snugly between the lungs in the mediastinum.2. About the size of a clenched fist.3. Shaped like an inverted cone with the apexdown and tilted to the left.4. The baseis broad and flat and is directed toward the right shoulder.B. Coverings of the Heart1. The heart is enclosed in a doubled walled sac called the pericardium.2. The pericardium is divided into two major layers:a. Fibrous pericardium=loose outer layer that protects the heart anchorsit to surrounding structures and prevents the heart from over filling.b. Serous pericardium=a thin slippery inner membrane composed of two layers.i. Parietal layerlines the internal surface of the fibrous pericardium.ii. Visceral layer(or epicardium) is the layer next to the heart itself.c. Pericardial cavityis the space between the parietal and visceral layers which contains a film of serous fluidthat lubricates the layers so they glide smoothly against each other.C. Wall of the Heart1. Epicardium= (or visceral layer of serous pericardium) outermost layer.2. Myocardium=middle layer composed mainly of cardiac muscle and responsible for contractions.3. Endocardium=inner layer composed of squamous epithelium lines the cavities of the heart and blood vessels and covers the valves.D. Chambers of the Heart1. Two upper atria(R and L) which serve as receiving chambers are covered by the external flaps called auricles. Because the walls look as if they were raked with a comb, the muscle within these
.2. Two lower ventricles(R and L) which serve as distribution chambers.
3. The chambers are separated by septa:

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture