1. Biology 212 Anatomy & Physiology I
The Heart

3. Heart:
Mass: g
Located in center of
thorax (mediastinum)
Anterior to vertebrae
Posterior to sternum &
2nd through 6th rib
Superior to diaphragm
Surrounded by lungs
All vessels, nerves, etc. enter or leave superior end ("base")

4. Layers of Heart:
(Outer Surface) Epicardium - Thin, connective tissue
Myocardium - Thick, cardiac muscle
(Inner Surface) Endocardium - Thin, connective tissue
Simple squamous epithelium
lines inner surface, next to blood

5. Myocardium: Cardiac Muscle

6. Heart surrounded by double-layered pericardium
Visceral Layer
Parietal Layer
Serous Pericardium
Visceral Layer
Parietal Layer
Heart
Pericardial
Cavity

7. Heart surrounded by double-layered pericardium
Fibrous Pericardium
Serous Pericardium
Visceral Layer
Parietal Layer
Heart
Pericardial
Cavity

9. Anterior View
Left Atrium
Right Atrium
Left Ventricle
Right Ventricle

11. Anterior View Aorta Superior Vena Cava Pulmonary Trunk
Inferior Vena Cava

12. Anterior View Left Atrioventricular Sulcus
Right Atrioventricular Sulcus
Anterior Interventricular Suclus

13. Posterior View
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle

14. Posterior View Left Atrioventricular Sulcus
Right Atrioventricular Sulcus
Posterior Interventricular Suclus

15. Posterior View Superior Vena Cava Aorta Pulmonary Arteries
Inferior Vena Cava
Pulmonary Veins

17. Left Coronary Artery
Circumflex Coronary Artery
Right Coronary Artery
Anterior Interventricular Coronary Artery
Marginal Coronary Artery

18. Circumflex Coronary Artery
Right Coronary Artery
Posterior Interventricular Coronary Artery

20. Anterior Cardiac Veins
Great Cardiac Vein
Small Cardiac Vein

21. Great Cardiac Vein
Small Cardiac Vein
Middle Cardiac Vein
Coronary Sinus

23. Valves of the Heart:
Right Atrioventricular Valve
(Tricuspid valve)
Right Atrium to Right Ventricle

24. Valves of the Heart:
Right Atrioventricular Valve
Pulmonary Valve
(Right semilunar valve)
Right Ventricle to
Pulmonary Trunk

25. Valves of the Heart:
Right Atrioventricular Valve
Pulmonary Valve
Left Atrioventricular Valve (Bicuspid or Mitral valve)
Left Atrium to Left Ventricle

26. Valves of the Heart:
Right Atrioventricular Valve
Pulmonary Valve
Left Atrioventricular Valve
Aortic Valve
(Left semilunar valve)
Left Ventricle to
Ascending Trunk

27. Valves of the Heart:
Right Atrioventricular Valve
Pulmonary Valve
Left Atrioventricular Valve
Aortic Valve
Note: There are no valves controlling movement of blood
a) From superior or inferior vena cavae into right atrium
b) From pulmonary veins into left atrium

29. Sinoatrial Node
Atrioventricular
Node
Atrioventricular
Bundle (of His)
Bundle Branches
Purkinje fibers

30. Cardiac myocytes spontaneously depolarize:
Na+ constantly leaks into the cells, decreasing the voltage until threshold voltage is reached
Thereafter: contraction similar to what we discussed for skeletal muscle:

31. Cardiac myocytes spontaneously depolarize:
Na+ constantly leaks into the cells, decreasing the voltage until threshold voltage is reached
Thereafter: contraction similar to what we discussed for skeletal muscle:
Na+ / Ca++ gates open
Na+ and Ca++ flow into myocyte
K+ flows out of myocyte
Sarcoplasmic reticulum
releases Ca++ which binds onto thin myofilaments
Actin binding sites uncovered, form cross bridges with
myosin of thick myofilament
Action potential moves along sarcolemma and into the cell through transverse tubules

32. Contraction of the heart (or any one of its chambers) is Systole
Relaxation of the heart (or any one of its chambers) is Diastole
One systole followed by one diastole is one Cardiac Cycle

36. Flow of blood through the heart is controlled entirely by changes in pressure.
Blood always flows along its pressure gradient, from the area of higher pressure to an area of lower pressure.
The open or closed position of a valve depends entirely on the difference in pressure from one side to the other:
The higher pressure pushes the valve open or closed,

38. Assume the chambers of the heart and vessels have the following pressures:
Left ventricle = 115 mm Hg
Right ventricle = 5 mm Hg
Pulmonary trunk = 22 mm Hg
Superior vena cava = 2 mm Hg
Inferior vena cava = 2 mm Hg
Left atrium = 20 mm Hg
Right atrium = 10 mm Hg
Aorta = 125 mm Hg
Which valves of the heart will be open?
Which valves of the heart will be closed?

39. Terms to know:
Heart rate: The number of cardiac cycles per minute
Stroke volume: Volume of blood ejected from a
ventricle during a single systole.
Cardiac Output: Volume of blood pumped by a ventricle
in one minute
= (Heart rate) x (Stroke volume)
Cardiac Index: Volume of blood pumped by a ventricle per
minute per square meter of body surface

40. Given the following information:
a) Dr. Thompson's total blood volume is 5.8 liters
b) His heart ejects 75 ml of blood per contraction
c) His kidneys produce 320 ml of urine per hour
d) All of his wisdom teeth have been removed
e) His heart contracts 70 times per minute
f) His systolic blood pressure is 130 mmHg
g) His diastolic blood pressure is 80 mmHg
h) The pressure in his left ventricle changes between
1 mmHg and 133 mmHg during each cardiac cycle
Calculate his Heart Rate
Stroke Volume
Cardiac Output

41. Therefore: You can regulate your cardiac output, and
therefore your cardiac index, by:
a) Increasing or decreasing your heart rate
b) Increasing or decreasing your stroke volume
In fact: Your ventricles modify both heart rate and stroke
volume on a beat-by-beat basis.
This depends on how much the cardiac muscle cells are stretched during the preceding diastole, which itself depends on the volume of blood in the chamber
= Frank-Starling Law of Cardiac Contraction