1. CIRCULATORY System
Structure of the Heart

2. Size, Shape, and Location
Size of closed fist
5 inches long and 3.5 inches wide, weighs less than 1 pound (12-13 oz.)
In _____________ cavity
Apex
Conical tip
Lies on the diaphragm and points to the left of the body
Where the heartbeat is most easily felt and heard
Four chambers
Which are what?
*SEE FIGURE 13.3 PG 263*

3. Layers FIGURE 13-2 pg 264 Pericardium Myocardium Surrounds the heart
Double layer of fibrous tissue
b/t the 2 layers is a space filled with _________ fluid
Thin inner layer called:
Tough outer layer called:
Myocardium
Cardiac muscle tissue
Makes up a major portion of the heart

4. Layers continued Endocardium Septum Smooth tissue
Covers the heart valves and lines the blood vessels
Provides a smooth transit for the flowing blood
Septum
Thick, muscular wall separating it into right and left halves
*SEE FIGURE 13-4a PG 265*

5. Structures to and from the Heart
Superior and inferior vena cava
Large venous blood vessels which bring deoxygenated blood to the right atrium from all parts of the body
Coronary sinus
From the heart muscle to the right atrium
Pulmonary artery and vein
Artery: takes blood away from the right ventricle to the lungs for oxygen
Vein: bring oxygenated blood from the lungs to the left atrium
Aorta
Takes blood away from the left ventricle to the rest of the body

6. Chambers Atria (atrium) Ventricles (ventricle)
Upper 2 chambers of the heart
Aka auricle
Ventricles (ventricle)
Have a right and left
Lower chambers of the heart
*See figure 13-4 pg. 265*

7. Valves 4 valves which allow the blood to flow in only one direction
Tricuspid valve
b/t the right atrium and right ventricle
3 points of attachment (cusps)
Chordae tendinae: small fibrous bands connecting the edges of the valve to the papillary muscle; prevents inversion of the tricuspid valve
Mitral (bicuspid) valve
Located b/t left atrium and left ventricle
2 points of attachment

8. Valves continued
Semilunar valves are located where the blood leaves the heart
Pulmonary semilunar valve
Found at the opening of the pulmonary artery
Allows blood to travel from right ventricle into the artery and then into the _____________.
Aortic semilunar valve
At the opening of the ___________.
Allows blood to pass from the left ventricle into the aorta