The document describes the structure and function of the cardiovascular system. It discusses the location of the heart in the thoracic cavity and its dimensions. It describes the layers of the heart wall, the cardiac muscle tissue, and the physiology of cardiac muscle. It explains the heart chambers and valves, blood flow through the heart, and the coronary circulation. It also discusses electrocardiography and various cardiovascular conditions like angina, myocardial infarction, thrombosis, and peripheral vascular disease.

1. Cardiovascular System
Structure and location
Cardiac tissue & ECG
Coronary blood flow
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2. Associated Terms
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Systemic circulation
Pulmonary circulation
Arteries
Arterioles
Capillary beds
• Venules
• Veins
• Electorcardiography
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3. Location of the Heart
• Lies in the mediastinum of the thoracic
cavity – 2/3 of the heart mass lies to the
left of the body‟s midline
• Rests on the diaphragm
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5. Dimensions of the Heart
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Hollow, cone shaped organ
About the size of a person‟s closed fist
Weighs 300g
12 cm long
9 cm wide at broadest part
6 cm thick
Inferior point of (L) ventricle - Apex
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8. Pericardium
• Triple-layered sac
– Fibrous pericardium
– Serous pericardium
• Parietal layer
• Visceral layer
• Surrounds the heart
• Provides protection and confines the heart
to its position in the mediastinum
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9. Pericarditis & Cardiac
Tamponade
• Pericarditis – inflammation of the
pericardium
• Cardiac tamponade – build up of
fluid/blood within the pericardial space.
– Life threatening
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10. Structure of the Heart Wall
• Three layers:
– Epicardium (external layer – visceral layer of the
serous pericardium)
– Myocardium (middle layer – muscle layer)
– Endocardium (internal layer – thin layer of
endothelial tissue) Endocardium covers the valves
and is continuous with the endothelial lining of the
large blood vessels.
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11. Cardiac Muscle Tissue
• Involuntary striated muscle
• Muscle fibres are:
– Shorter, fatter and squarish in shape
compared to other striated muscle
– Exhibits branching – Y shape
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12. Cardiac Muscle Tissue
• Sarcoplasm is more abundant in cardiac
muscle tissue
• Mitochondria are larger and more
numerous
• Has limited reserves of Ca++ (Ca++
enters the muscle fibres from extracellular
fluid during contraction)
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13. Cardiac Muscle Tissue
• Intercalated discs connect each fibre with
its neighbour
• Gap junctions allow muscle action
potentials to spread from one muscle fibre
to another
• This connection allows connected units to
function as one
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15. Physiology of Cardiac Muscle
• Under normal resting conditions, muscle
fibres contract and relax about 75 times
per minute
• Cardiac muscle is greatly dependant on a
constant supply of oxygen
• Reliant on aerobic system to generate ATP
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16. Physiology of Cardiac Muscle
• Cells are capable of autorhythmicity
• Contraction is maintained for 10-15 times
longer than that of skeletal muscle due to
prolonged Ca++ delivery
• Refractory periods of several 1/10ths of a
second allows time for the chambers to fill
between contractions
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17. Action Potential of Cardiac
Muscle
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18. Heart Chambers
• Four chambers
– 2 - Atria
– 2 – Ventricles
• Anterior wall of the atrium is rough due to
internal muscular ridges called pectinate
muscles. Posterior wall is smooth
• Atria have an appendage called an auricle
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19. Ventricles
• Located below the atria
• Grooves known as coronary sulci separate
atria from ventricles and separate
ventricles
• Sulci provide a cradle for the coronary
vessels and hold a variable amount of fat
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20. Heart Sulci
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21. Chamber Divisions
• Interatrial septum divides the atria
• Fossa ovalis – an oval depression is the
remnant of the foramen ovale
• Interventricular septum separates the
ventricles
• Irregular ridges on the internal surfaces of
the ventricles are called the trabeculae
carneae
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22. Wall Thickness
• Wall thickness depends on the function of
the area
• Atrial walls are thin
• Left ventricular wall is two to four times
thicker than right
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24. Valves of the Heart
Five valves
• Atrioventricular valves
– Tricuspid valve
– Bicuspid valve (Mitral valve)
• Semilunar valves
– Pulmonary valves (2)
– Aortic valve
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25. Papillary Muscles and Chordae
Tendineae
• Chordae tendineae – tendon like cords
connect the pointed ends and under
surfaces of the cuspid valves to the
papillary muscles.
• Papillary muscles lie on the inner surface
of the ventricles
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28. Tricuspid Valve
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29. Blood Flow through the Heart
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30. (R) Atria to (R) Ventricle
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31. (R) Ventricle to Pulmonary Artery
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32. Lungs to (L) Atrium
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33. (L) Atrium to (L) Ventricle
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34. (L) Ventricle to Aorta
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35. Coronary Blood Flow
• The walls of the heart have their own
blood supply – coronary vessels
• The arteries of the coronary circulation
encircle the heart like a crown
• Little blood flows through these vessels
during contraction
• Coronary circulation takes place during
diastole
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36. Coronary Blood Flow
• The entrance of the coronary arteries is
located directly behind the leaves of the
aortic valve
• During systole, the arteries are occluded
by the open valve
• When valve closes, blood flows into the
coronary arteries
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37. Coronary Circulation
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38. (L) Coronary Artery Angiogram
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39. (R) coronary Artery Angiogram
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40. Coronary Veins
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41. Conduction System
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42. ECG
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43. ECG Lead Placement
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44. Wave forms
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45. 12 Lead ECG
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46. Angina
• Reduced O2 / blood supply to an area of
myocardium
– Discomfort in the chest (often but not always)
– Heavy, pressing, squeezing, “couldn‟t get my
breath”, “not really a pain”
– Cold sweat
– Onset with exercise (or not)
– Offset with rest +/- medication
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47. Myocardial Infarction
• Lack of blood supply to an area of
myocardium
– Symptoms similar to angina but more severe
– Ongoing, not relieved by rest +/- nitrate
medications
– Cold sweat, pallor
– Change to conscious state
– Life threatening
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48. Thrombosis
• Stationary clot
– May occur in any vessel where blood flow is
impeded (arterial or venous)
– Symptoms depend on location
• Deep Vein Thrombosis (leg)
– Pain on walking or standing
– Heat or swelling of the limb
– Pain reduced when leg elevated
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49. Clot Embolus
• Pulmonary
– Sudden
– Breathless, hypoxic, disorientated
– Death
• Cerebral
– Sudden
– Slurring speech, weakness on one side,
change in conscious state, coma, death
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50. Peripheral Vascular Disease
• Narrowing of the arteries in the arms and
legs
– Mild – no symptoms
– Progressive – claudication, rest pain or
vascular ulceration
– Cold limb
– Painful when elevated
– Commonly associated with diabetic patient
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51. Vascular Ulcer
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52. References
• Tortora, GJ & Grabowski, SR (1996) Principles of
Anatomy and Physiology (8th ed). New York.
HarperCollins Publishers Inc. (580-589)
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www.firearmstactical.com/images/Wound%20Profiles/Cardiovascular%20St
ructures.jpg
www.abe.msstate.edu/…/03/cva_struc_funct.html
www.info.med.yale.edu/intmed/cardio/imaging/findings/normal_heart/graphi
cs/rad1.gif
www.bami.us/CardiacAnatomy.html
www1.shimadzu.com/…/angio/app_data.html
www.womensfitness.net/reena_img/coronaryartery.gif
connection.lww.com/Products/porth7e/Ch26.asp
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53. References
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www.numed.co.uk/electrodepl.jpg
www.merck.com/media/mmhe2/figures/fg021_1.gif
www.fammed.wisc.edu/pcc/ecg/axis.html
www.gonzaga.k12.nf.ca/…/biology/biology.html
http://www.diabetes.usyd.edu.au/foot/Pvdx1.html
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