Chapter 20 - Cardiovascular System

What does the left atrium receive blood from?

From the four pulmonary veins.

Describe the mitral valve

Left atrioventricular valve, has leaf-like cusps attached to cone-shaped papillary muscles by tendons called chordae tendineae

Describe the aortic valve

Left semilunar valve from the left ventricle to systemic circulation.

Describe extrinsic regulation of the heart

Neural Control - Parasympathetic stimulation by the vagus nerve -Sympathetic stimulation by the cardiac nerves, releasing epi and norepi Hormonal Control -Adrenal medulla releases epi and norepi.

Describe the path of the heart's conduction system

Action potentials originate in the sinoatrial node, travel to the atrioventricular node, through the AV bundle (Bundle of His) that divides into the right and left bundle branches, then into the Purkinje fibers.

What is the heart skeleton?

Consists of plate of fibrous connective tissue between atria and ventricles. Fibrous rings around valves to support. Serves as electrical insulation between atria and ventricles, and site for muscle attachment.

Describe the location of the heart

Deep in the thoracic cavity between the lungs, located in the mediastinum. Apex is located to the left of midline.

What are the three layers of tissue in the heart wall?

Epicardium: Serous membrane, smooth outer surface of the heart Myocardium: Middle layer composed of cardiac muscle cell Endocardium: smooth inner surface of heart.

Describe intrinsic regulation of the heart

Results from normal functional characteristics, not on neural or hormonal regulation. Preload: The greater the stretch, greater the force of contraction (Starling's Law) Afterload: Pressure that the contracting ventricles must overcome to move blood into the aorta.

Describe the tricuspid valve

Right atrioventricular valve, has leaf-like cusps attached to cone-shaped papillary muscles by tendons called chordae tendineae.

Describe the basic anatomy of coronary arteries

Right coronary exits aorta just superior to point where aorta exits heart; lies in coronary sulcus. Extends to posterior aspect of heart. Branches into right marginal and posterior interventricular. Left coronary exits aorta near right coronary. branches into anterior interventricular artery, left marginal artery, and circumflex artery.

Describe the pulmonary valve

Right heart valve from the right ventricle to the pulmonary circulation. Semilunar, has a cusp shaped like a cup. If cup is full, valve is closed; if cup is empty, valve is open.

Describe cardiac muscle

Striated muscle with one or two nuclei. Connected to adjacent cells by intercalcated disks, which enhance physical and electrical connections between cells. Desmosomes hold the cells together, and gap junctions allow cytoplasm to flow freely between cells. Allows heart muscle cells to function as a single unit, with coordinated contractions.

What openings does the right atrium receive blood from?

Superior vena cava, inferior vena cava, and coronary sinus.

Describe the basic anatomy of coronary veins

The great cardiac vein and small cardiac vein drain the right margin of the heart. The coronary sinus is where all coronary veins meet and drain directly into the right atrium.

Where does the left side of the heart pump blood to?

The left side of the heart pumps blood through the systemic circulation, which delivers O2 and nutrients to all the remaining tissues of the body. From those tissues, CO2 and other waste products are carried back to the right side of the heart.

What is the pericardium?

The pericardial sac, with a outer fibrous pericardium and an inner serous pericardium. The serous pericardium has two parts: a parietal and visceral layer. The visceral layer is also called the epicardium. In between the layers is a pericardial cavity filled with pericardial fluid.

Where does the right side of the heart pump blood to?

The right side of the heart pumps blood through the pulmonary circulation, which carries blood to the lungs, where the CO2 diffuses from the blood into the lungs and O2 diffuses from the lungs into the blood.

Describe the external anatomy of the heart

The two atria, right and left, are located superiorly, and the two ventricles, right and left, and located inferiorly. The superior and inferior venae cava enter the right atrium. The pulmonary veins enter the left atrium. The pulmonary trunk (artery) exits the right ventricle, and the aorta exits the left ventricle