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1. DR MUMA
*
11/08/2020
DR MUMA

2. *
*By the end of this class students should be able
to describe
*Location of the heart and its orientation
*Structure of the heart
*Pathway of blood through the heart
*Cardiac muscle tissue
*Conducting system and innervation
*Blood supply to the heart
*Disorders of the heart (common)
11/08/2020
DR MUMA

3. *
*Cardiovascular system consist of the HEART,
BLOOD VESSELS and blood.
*The system helps to circulate blood with its
contents throughout the body (CIRCULATORY
SYSTEM)
*Circulation is achieved through TWO circuits
*Pulmonary circuit
*Systemic circuit
11/08/2020
DR MUMA

4. *
A= HEART
B= LUNGS
C= BODY TISSUES
• PULMONARY CIRCUIT
• Blood moves from the right side of the
heart to the lungs and back to the left side
of the heart
• SYSTEMIC CIRCUIT
• Blood moves from the left side of the heart
to the body tissues and back to the right
side of the heart
A
B B
C
right
left
11/08/2020
DR MUMA

5. *
*Heart average size is about the size of a fist
*About 250 to 350grams
*It is located in the thorax (mediastinum)
posterior to sternum and costal cartilages and
rests on superior surface of the diaphragm
*Assumes an oblique position
11/08/2020
DR MUMA

6. *Superior right border- lies behind
costal cartilage of third rib joins
the sternum
*Superior left border- lies at the
costal cartilage of the second rib
*Inferior right border- lies at the
costal cartilage of sixth rib
*Apex – lies in fifth intercostal
space at midclavicular line
11/08/2020
DR MUMA

7. 11/08/2020
DR MUMA

8. *Heart is surrounded by a sac called
PERICARDIUM
*It protects it, helps create a frictionless
environment for the heart to contract and
relax
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DR MUMA

9. *
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DR MUMA

10. *
*Triple layered sac
*It has an outer layer of
strong dense
connective tissue
called fibrous
pericardium
Heart chamber
myocardium
Pericardial cavity
11/08/2020
DR MUMA

11. *
*Deep to fibrous
pericardium is a double
layered serous
pericardium
*The layer which adheres
to fibrous pericardium is
called the parietal
pericardium
*Visceral layer
(Epicardium) adheres to
myocardium
myocardium
Pericardial cavity
Heart chamber
11/08/2020
DR MUMA

12. *
*Wall of the heart has
three layers
*Epicardium (viseral
pericardium)
*Myocardium (cardiac
muscle)
*Fibrous cardiac
skeleton
*Endocardium
(endothelium)
11/08/2020
DR MUMA

13. *
*Heart has four chambers
*Two atria and two ventricles
*Divided by septum
*Atria are receiving chambers
*Ventricles are pumping
chambers
*Four valves( one way flow of
blood)
*Two semilunar valves and
two AV valves
RA
RV
LA
LV
11/08/2020
DR MUMA

14. *
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15. * 11/08/2020
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16. *
• Short branched cells
• One or two large central
nucleus
• Striated
• Have intercalated discs
connects adjacent cells
by cell junctions
• Fasciae adherens
(desmosomes-like)
• Gap junctions
• Involuntary
• Highly resistant to
fatigue
11/08/2020
DR MUMA

17. *
*Specialised cardiac
muscle cells
*Sinoatrial (SA) node
*pacemaker
*Atrioventricular node
*AV bundle (Of His)
*Left and right bundle
branches
*Purkinje fibers
11/08/2020
DR MUMA

18. *
*Nerves to the heart consist
of
*Visceral sensory
*Parasympathetic
*From vagus nerve
*Decreases HR
*Sympathetic
*Cervical and thoraci
sympathetic chain
*Increases the HR
11/08/2020
DR MUMA

19. *
*Arterial supply is by
coronary arteries
(Coronary circulation)
*Left and right coronary
arteries
*Left coronary artery is
short and divides into
anterior
interventricular artery
and circumflex artery
11/08/2020
DR MUMA

20. *
Venous drainage of the
heart
*Largest is coronary
sinus which returns
almost all the venous
blood from the heart
to the right atrium
11/08/2020
DR MUMA

21. *Cardiac veins carry
deoxygenated blood from
the wall into the right
atrium
*Coronary sinus (largest)
*Great cardiac vein
*Small cardiac vein
*Middle cardiac vein
*Anterior cardiac vein
11/08/2020
DR MUMA

22. * 11/08/2020
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23. * 11/08/2020
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24. *
*Inflammation (Pericarditis, myocarditis,
endocarditis)
*Pericardial effusion
*Valvular heart diseases
*Arrhythmias
*Congenital heart diseases
*Myocardial Infarctions
*Heart failure
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DR MUMA

25. * END OF PART 1
*
11/08/2020
DR MUMA