1. Cardiovascular System Notes:
The Heart

2. The human heart creates enough pressure to squirt blood 30 feet.
Interesting Cardiovascular System Facts
The human heart creates enough pressure to squirt blood 30 feet.

3. NOTES – THE HEART
Location:
cavity between the lungs, 2/3 left of midsagittal
roughly the size of a fist

4. Figure 18.2b Location of the heart in the mediastinum.
Left lung
Body of T7
vertebra
Posterior
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5. Figure 18.2c Location of the heart in the mediastinum.
Superior
vena cava
Aorta
Parietal pleura
(cut)
Pulmonary
trunk
Left lung
Pericardium (cut)
Apex of heart
Diaphragm
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6. Heart Anatomy
PERICARDIUM
outer membrane of the heart
2 layers
1. Parietal pericardium: external (outer) layer
2. Visceral pericardium (epicardium): part of the heart wall

7. Functions:
protection – physical barrier
anchors heart to other structures
provides lubrication to reduce friction – allows the heart to beat easily

8. THE HEART WALL
3 layers
1. Epicardium: outer portion (visceral pericardium)
EPICARDIUM

9. 2. Myocardium: middle layer consists of twisted cardiac muscle
THIS IS THE LAYER THAT ACTUALLY CONTRACTS
MYOCARDIUM

10. 3. Endocardium: inner layer made of epithelial tissue

11. Figure 18.3 The pericardial layers and layers of the heart wall.
Pulmonary
trunk
Fibrous pericardium
Parietal layer of serous
pericardium
Pericardium
Myocardium
Pericardial cavity
Epicardium (visceral
layer of serous
pericardium)
Heart
wall
Myocardium
Endocardium
Heart chamber
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12. Homeostatic Imbalance
Pericarditis
Inflammation of pericardium
Roughens membrane surfaces  pericardial friction rub (creaking sound) heard with stethoscope
Cardiac tamponade
Excess fluid sometimes compresses heart  limited pumping ability
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13. The Pulmonary and Systemic Circuits
Receiving chambers of heart:
Right atrium
Receives blood returning from systemic circuit
Left atrium
Receives blood returning from pulmonary circuit
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14. The Pulmonary and Systemic Circuits
Pumping chambers of heart:
Right ventricle
Pumps blood through pulmonary circuit
Left ventricle
Pumps blood through systemic circuit
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15. Figure 18.1 The systemic and pulmonary circuits.
Capillary beds of
lungs where gas
exchange occurs
Pulmonary Circuit
Pulmonary
arteries
Pulmonary veins
Aorta and branches
Venae
cavae
Left
atrium
Left
ventricle
Right
atrium
Heart
Right
ventricle
Systemic Circuit
Capillary beds of all
body tissues where
gas exchange occurs
Oxygen-rich,
CO2-poor blood
Oxygen-poor,
CO2-rich blood
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16. Cardiac muscle bundles
Figure The circular and spiral arrangement of cardiac muscle bundles in the myocardium of the heart.
Cardiac
muscle
bundles
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17. HEART CHAMBERS
4 chambers
Atrium (left/right atria)
divided by the INTERATRIAL SEPTUM
Function of Atria: receives blood from veins
(pig heart)

18. RIGHT ATRIA
receives blood from superior & inferior vena cava
blood that’s been used
oxygen poor – high in CO2

19. LEFT ATRIA
receives blood from pulmonary veins
coming from lungs
rich in oxygen

20. Ventricles (left/right)
muscular pumps – divided by INTERVENTRICULAR SEPTUM
(pig heart)

21. RIGHT VENTRICLE
receives blood from the right atria (O2 poor)
pumps blood to the lungs through the PULMONARY ARTERIES

22. LEFT VENTRICLE
receives blood (O2 rich) from the left atrium
pumps blood to the body through the AORTA

23. Left Right ventricle Interventricular septum
Figure Anatomical differences between the right and left ventricles.
Right
ventricle
Interventricular
septum
Left
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24. Systemic Circulation
heart – lungs – heart – body – heart

25. HEART VALVES (4)
allow for “one way” circulation
2 Atrioventricular Valves (AV valves)
1. Tricuspid Valve: between right atria and right ventricle

26. 2. Bicuspid or Mitral Valve: between left atria and left ventricle
heavier & stronger of the two

27. (left atrioventricular) valve
Figure 18.6a Heart valves.
Pulmonary valve
Aortic valve
Area of cutaway
Mitral valve
Tricuspid valve
Myocardium
Mitral
(left atrioventricular)
valve
Tricuspid
(right atrioventricular)
valve
Aortic valve
Pulmonary valve
Cardiac
skeleton
Anterior
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28. (left atrioventricular) valve
Figure 18.6b Heart valves.
Pulmonary valve
Aortic valve
Area of cutaway
Mitral valve
Tricuspid valve
Myocardium
Mitral
(left atrioventricular)
valve
Tricuspid
(right atrioventricular)
valve
Aortic valve
Pulmonary valve
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29. Chordae tendineae attached to tricuspid valve flap Papillary muscle
Figure 18.6c Heart valves.
Pulmonary valve
Aortic valve
Area of cutaway
Mitral valve
Tricuspid valve
Chordae tendineae attached
to tricuspid valve flap
Papillary
muscle
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30. Pulmonary valve Aortic valve Area of cutaway Mitral valve
Figure 18.6d Heart valves.
Pulmonary valve
Aortic valve
Area of cutaway
Mitral valve
Tricuspid valve
Opening of inferior
vena cava
Mitral valve
Chordae
tendineae
Tricuspid valve
Myocardium
of right
ventricle
Interventricular
septum
Papillary
muscles
Myocardium
of left ventricle
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31. CHORDAE TENDINAE and papillary muscles stop valves from being folded backwards

32. 3. Pulmonary Semilunar Valve: between the pulmonary artery and right ventricle

33. 4. Aortic Semilunar Valve: between aorta and left ventricle

34. Animation
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35. Homeostatic Imbalance
Two conditions severely weaken heart:
Incompetent valve
Blood backflows so heart repumps same blood over and over
Valvular stenosis
Stiff flaps – constrict opening  heart must exert more force to pump blood
Valve replaced with mechanical, animal, or cadaver valve
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36. Pathway of Blood Through the Heart
Pulmonary circuit
Right atrium  tricuspid valve  right ventricle
Right ventricle  pulmonary semilunar valve  pulmonary trunk  pulmonary arteries  lungs
Lungs  pulmonary veins  left atrium
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37. Pathway of Blood Through the Heart
Systemic circuit
Left atrium  mitral valve  left ventricle
Left ventricle  aortic semilunar valve  aorta
Aorta  systemic circulation
PLAY
Animation: Rotatable heart (sectioned)
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38. Functional blood supply to heart muscle itself
Coronary Circulation
Functional blood supply to heart muscle itself
Delivered when heart relaxed
Left ventricle receives most blood supply
Arterial supply varies among individuals
Contains many anastomoses (junctions)
Provide additional routes for blood delivery
Cannot compensate for coronary artery occlusion
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39. Coronary Circulation: Arteries
Arteries arise from base of aorta
Left coronary artery branches  anterior interventricular artery and circumflex artery
Supplies interventricular septum, anterior ventricular walls, left atrium, and posterior wall of left ventricle
Right coronary artery branches  right marginal artery and posterior interventricular artery
Supplies right atrium and most of right ventricle
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40. Figure 18.11a Coronary circulation.
Aorta
Superior
vena cava
Anastomosis
(junction of
vessels)
Right
atrium
coronary
artery
ventricle
marginal
Posterior
interventricular
Anterior
Left
Circumflex
Left atrium
Pulmonary
trunk
The major coronary arteries
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41. Homeostatic Imbalances
Angina pectoris
Thoracic pain caused by fleeting deficiency in blood delivery to myocardium
Cells weakened
Myocardial infarction (heart attack)
Prolonged coronary blockage
Areas of cell death repaired with noncontractile scar tissue
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42. Microscopic Anatomy of Cardiac Muscle
Cardiac muscle cells striated, short, branched, fat, interconnected, 1 (perhaps 2) central nuclei
Connective tissue matrix (endomysium) connects to cardiac skeleton
Contains numerous capillaries
T tubules wide, less numerous; SR simpler than in skeletal muscle
Numerous large mitochondria (25–35% of cell volume)
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43. Figure 18.12a Microscopic anatomy of cardiac muscle.
Intercalated
discs
Cardiac
muscle cell
Nucleus
Gap junctions
Desmosomes
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44. Microscopic Anatomy of Cardiac Muscle
Intercalated discs - junctions between cells - anchor cardiac cells
Desmosomes prevent cells from separating during contraction
Gap junctions allow ions to pass from cell to cell; electrically couple adjacent cells
Allows heart to be functional syncytium
Behaves as single coordinated unit
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