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Chapter 15
Cardiovascular System
Organs
• Heart - begins beating in the 4th week of development.– Pumps 7,000 liters of blood each day.– Contracts 2.5 million times in a lifetime.
• Closed Vessel System– Arteries - carry blood away from the
heart.– Veins - carry blood toward the heart.– Capillaries - attach arteries and veins.
Function
• Circulates blood to every cell in the body and removes waste.
The Heart
• Location and Size– Size of a man’s fist
(14 cm long and 9 cm wide)
– Lies within the mediastinum - behind sternum (rests on diaphragm).
– 2/3 of the heart is on the left side of the body.
– Apex is the lower, left “point” of the heart.
• Stethoscope is placed here to count the beats.
The Heart • Coverings
– Pericardium - sac around the heart - loose-fitting• Fibrous - tough white outer
covering, • Serous parietal - smooth
lining of the fibrous sac.– Epicardium - covers
surface of the heart - smooth• Also called serous visceral
pericardium– Pericardial space - area
between pericardium and epicardium• Contains fluid - pericardial
fluid• Lubricates beating heart• Pericarditis -
inflammation of pericardium due to infection - linings stick together, very painful.
The Structure of the Heart
• The wall of the heart:– Epicardium –
reduces friction.– Myocardium – thick
contractile middle layer, high in mitochondria.
– Endocardium – delicate inner layer.
The Structure of the Heart Continued
• Cavities– Upper – atria– Lower – ventricles
• Larger and thicker walled
• Carry heavier pumping burden
• Left is thickest – has to pump blood to all parts of the body
The Structure of the Heart Continued
• Valves and Openings• Blood flows in one
direction.– Cuspid valves – between
cavities(atria and ventricles)
• Bicuspid (mitral) valve - left cavities.
Valve has 2 cusps or leaflets. Also called the leftatrioventricular valve. • Tricuspid valve - right
cavities. Valve has 3 cusps or leaflets.Also called the rightatrioventricular valve.
The semi-lunar valve moves blood out of the heart to the aorta and pulmonary artery.
i.Cusps of valve are half moon shaped (‘lunar’)Found at the base of thepulmonary arteries (called thepulmonary valve) and at thebase of the aorta (called theaortic valve)
•Attached by fibrousstrings called chordaetendineae to the papillarymuscles.
Tricuspid valve repair
A murmer is an abnormal sound that identifies the leakage of blood though valves in the wrong direction
4 2
5
6
10
89 - Apex
12
11 – left coronary artery
13
14
15
16
(auricle)
(auricle)
Left auricle
Right auricle
Auricle = A small, earlike projectionthat extends anteriorly from the atrium.
18
1. Aortic arch
2 . SuperiorVena cava
3.RightPulmonaryArtery
4. Pulmonary trunk
5. Right Pulmonary Veins
6. PulmonaryValve
7. RightAtrium
8. Tricuspid valve
9. Right ventricle 10. InferiorVena cava
11. Aorta
12. InterventricularSeptum
13. Left ventricle
14. Bicuspid valve (Mitral valve)
15. Aortic valve
16. Left atrium
17. Left pulmonaryVeins18. Left pulmonaryartery12
13
45
67
89
10
11
13
14
15
16
172
The Structure of the Heart Continued
• Blood Supply– Ventricles get blood from the right and
left coronary arteries. – Atria get blood from the small branch
coronary artery. – Anastomosis is branching of the main
arteries (“detours”)– Myocardial infarction - death of the heart
muscles due to a clot (heart attack).
Blood Vessels
• Structure– Outer – fibrous tissue,
keeps firm– Middle – muscle,
constriction, and dilation.
– Inner – endothelium - capillaries
Blood Vessels Continued
• Function– Transportation of nutrients to cells
• Capillaries perform this function• Arteries = distributors arterioles
capillaries venules veins • Veins = carry and pool blood
Blood Vessels Continued
• Main Blood Vessels– ascending aorta– aortic arch– subclavian– common carotid – common iliac
Ascending
Aorta
Blood Vessels Continued
Blood Vessels Continued
• Portal Circulation– Organs that do not pour blood into
inferior vena cava.– Blood sent to the liver by the portal
vein.
Blood Vessels Continued
• Fetal Circulation– Gets oxygen and food from mother, not
own lungs and digestive tract.– Additional vessels
•Umbilical arteries (2) – carry fetal blood to placenta
•Placenta – exchanges oxygen and other substances between mother and fetus
•Umbilical vein – returns oxygenated blood to liver of fetus
•Foramen ovale – opening between right and left atria bypass lungs, closes with first breath.
Shed at birth