Chapter 18 Study Guide

Name the coverings of the heart and describe the functions of the fibrous pericardium.

Pericardium - Double wall

1. Fibrous Pericardium - Protects, anchors the heart, and prevents overfilling

2. Serous Pericardium - Double sac

   • Parietal layer - internal surface

   • Visceral (epicardium) -

   • Serous Cavity - The fluid

Describe the three layers of the heart wall. What is the function of the myocardium?

1. Epicardium - external surface

2. Myocardium - Cardiac muscle that functions as the layer that contracts

3. Endocardium - sheet of squamous epithelium

Name the 3 veins which return blood to the right atrium

1. Superior Vena Cava

2. Inferior Vena Cava

3. Coronary Sinus

Name the heart valves and describe their location, function, and mechanism of operation.

Atrioventricular Valves - Between the Atriums and Ventricles; keeps blood unidirectional; Opens when pressure builds in Atriums, but closes and balloons once Ventricular pressure increases.

• (1)Tricuspid Valve - Between right Atria and right ventricle; deoxygenated

• (3) Mitral Valve - Between left Atria and left ventricle; oxygenated

Semilunar Valves - Between Ventricles and the main arteries; keeps blood from back flowing into Ventricles after contraction; Pops open to release blood into Aortic SL and Pulmonary SL, but shuts once pressure in arteries build.

• (2) Pulmonary Valve - Between right ventricle and Pulmonary artery; leaves to get deoxygenated

• (4)Aortic Valve - Between left ventricle and Aorta; leaves to supply body

What is the function of the chordae tendineae?

Anchors the AV valves to prevent them from collapsing

Trace the pathway of blood through the heart. (Flip to see correct pathway)

True or False? Veins always carry oxygen-poor blood, and arteries oxygen-rich blood.

False

Name the major branches and describe the distribution of the coronary arteries. What is their function?

• Left coronary artery

  • Anterior interventricular artery - supplies interventricular

    sulcus, interventricular septum and anterior walls of both

    ventricles

  • Circumflex artery - supplies the left atrium and the posterior

    walls of the left ventricle

• Right coronary artery

  • Right marginal artery - supplies the myocardium of the

    lateral right side of the heart

  • Posterior interventricular artery - supplies the posterior ventricular walls

What is the result of coronary artery blockade?

Myocardial infarction (heart attack)

What is the coronary sinus?

Vein

How does the structure and function of cardiac muscle cells differ from skeletal muscle fibers?

Cardiac muscles has less, but thicker t-tubules and their SR is less convoluted. Because it can contract without neural stimulation, has many more mitochondria.

What structures can you find in the intercalated discs of cardiac cells? What is their function?

Desmosomes - Gap junctions

Allow electrical signals to go throughout the cells

What is a functional syncytium? Which structures of the intercalated discs allow the myocardium to function as a functional syncytium?

Functional Syncytium means the entire heart works together

Ca2+ is needed for muscle contraction. What is the source of Ca2+ for skeletal and cardiac muscle fiber contraction?