1. The Heart & Circulation
Lab Activity #7.1
The Heart & Circulation

2. Most simply stated, the major function of the cardiovascular system is TRANSPORTATION.

3. Substances carried in the blood include…
Oxygen
Carbon Dioxide
Nutrients
Cell wastes
Hormones

4. The Heart Size of a fist Weighs less than a pound
Apex directed toward left hip, and rest on diaphragm
Bulk of mass between 2nd and 6th rib
About 2/3 of heart is left of median

6. Interesting facts… The heart beats 100,000 times a day
Approximately 35 million times a year
2.5 billion times during the average life span
Your 6 quarts (1.5 gallons) of blood pumped through your body 1,000 times per day
That’s 6000 quarts (1,500 gallons) of fluid that your heart pumps every day

7. Pericardium Double sac of serous membrane around the heart
Visceral pericardium (epicardium)
Next to heart
Actually part of heart wall
Parietal pericardium
Outside layer
Anchors heart to surrounding structure
Serous fluid fills the space between the layers of pericardium; eliminates friction

8. Heart Wall Three layers Epicardium Outside layer
AKA visceral pericardium
Connective tissue layer

9. Heart Wall Three layers Myocardium Middle layer Mostly cardiac muscle
Layer that contracts

10. Heart Wall Three layers Endocardium Inner layer
Thin sheet of Endothelium (simple squamous membrane)

11. Four Chambers of the Heart
Atria – on top
Receiving chambers
Atrium is singular!
Auricle is lateral “pouching” of each atrium
Ventricles – on bottom
Discharging chambers
Left ventricle has thickest wall because it pumps blood to rest of body!
Lined with endocardium to help blood flow smoothly through

12. Heart Supporting Structures
Superior Vena Cava: carries oxygen-poor blood from body to heart (right atrium)
Inferior Vena Cava: carries oxygen-poor blood from body to heart (right atrium)

13. Heart Supporting Structures
Pulmonary trunk: carries oxygen-poor blood from heart (right ventricle) to pulmonary arteries
Pulmonary arteries: carries oxygen-poor blood from pulmonary trunk to lungs
Only artery to carry O2 poor blood!

14. Heart Supporting Structures
Pulmonary Veins: carries oxygen-rich blood from lungs to heart (left atrium)
Only vein to carry O2 rich blood!
Aorta: carries oxygen-rich blood from heart (left ventricle) to body
Largest artery in body

15. The heart does 2 types of circulation…
Pulmonary Circulation
Leaves from right side of heart
Delivers CO2 waste to lungs, and picks up O2 to take back to heart
Returns to left side of heart
Systemic Circulation
Leaves from left side of heart
Delivers O2 and nutrients to body, and picks up CO2 to take back
Returns to right side of heart

18. The Valves The heart is equipped with four valves…
Allow blood to flow in only ONE direction through the heart chambers
Have cusps (flaps) that open & close

19. The Valves
Have CHORDAE TENDINEAE (“heart strings”) which hold the cusps in place
Prevent backflow of blood

21. Atrioventricular (AV) Valves
Located between the atrial and ventricular chambers
Left AV Valve:
Bicuspid (Mitral) valve
2 cusps
Right AV Valve:
Tricuspid valve
3 cusps
OPEN during heart relaxation and CLOSED when ventricles contracting

22. FYI: Why the special name for the bicuspid valve?
Early anatomists thought that the bicuspid (mitral) valve looked like a bishop’s miter (their funny hat)

24. Semilunar Valves
Guards the bases of the two large arteries leaving the ventricular chambers
Pulmonary Semilunar Valve (right)
Aortic Semilunar Valve (left)
Both have THREE cusps
CLOSED during heart relaxation and OPEN when ventricles contracting

29. Blood Supply to Heart
The blood supply that oxygenates and nourishes the heart itself (myocardium) is provided by the right & left CORONARY ARTERIES, which branch from the base of the AORTA and encircle the heart in the ATRIOVENTRICULAR GROOVE.

30. Coronary arteries branch off from the base of the aorta
Right Coronary Artery breaks into…
Posterior interventricular (on back side of heart)
Marginal
Left Coronary Artery breaks into…
Anterior interventricular
Circumflex

33. Blood Supply to Heart
The heart (myocardium) is drained by several CARDIAC VEINS, which empty into the CORONARY SINUS, which in turn, empties into the RIGHT ATRIUM.

34. Cardiac Veins include…
Great cardiac vein
Anterior cardiac vein
Small cardiac vein
Middle cardiac vein (on posterior side of heart)

38. Labeling The Heart A: Aortic Arch (Aorta) B: Superior Vena Cava
C: (Right) Pulmonary Veins
D: Right Atrium
E: Tricuspid Valve
AB: Right Ventricle
AC: Inferior Vena Cava

39. Labeling The Heart AD: (Left) Pulmonary Artery AE: Left Atrium
BC: Bicuspid (Mitral) Valve
BD: Aortic Semilunar Valve
BE: Left Ventricle
CD: Aorta

40. Labeling The Heart Let’s Also Label… Pulmonary Trunk
Pulmonary Semilunar Valve
Septum
Apex