Download 4. Anatomy of Heart... - College of Pharmacy at Howard University

Jessica Pinchinat 2016
Howard University College of Pharmacy
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The cardiovascular system consists of the
blood, the heart, and blood vessels
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Length: ~12cm (5 inches)
Width [widest point]: ~9cm (3.5 inches)
Thickness: ~6cm (2.5 inches)
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The heart is located in the mediastinum:
 This is a region between the lungs and between
the sternum and vertebral column. The heart is
located near the midline of the thoracic cavity.
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About 2/3rds of the mass of the heart lies to
the left of the body’s midline
Apex – formed by the left ventricle of the
heart
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A membrane that surrounds and protects the
heart.
It confines the heart to its position in the
mediastinum
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It consists of two principal parts.
It consists of:
 Fibrous pericardium
 Serous pericardium
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Fibrous pericardium – prevents overstretching
of the heart, provides, protection, and anchors
the heart in the mediastinum
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Serous pericardium – a thinner more delicate
membrane that forms a double layer around
the heart.
 Parietal layer (outer) of the serous pericardium is
fused to the fibrous pericardium
 Visceral layer (inner) of the serous pericardium
adheres tightly to the surface of the heart. Also
known as the epicardium.
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Pericardial cavity – the area between the
parietal and visceral layers of the serous
pericardium.
 Contains the pericardial fluid – a slippery
lubricating secretion of the pericardial
membranes that reduces friction between the
serous pericardial membranes as the heart moves
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The wall of the heart is composed of three
layers.
 Epicardium – gives a smooth slippery texture to
the outermost surface of the heart.
 Myocardium – makes up approximately 95% of
the heart wall and is responsible for the pumping
action.
 Endocardium – provides a smooth lining for the
heart chambers and covers the heart valves
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The heart contains four chambers.
The upper two receiving chambers are the
atria (entry halls or chambers)
The lower two pumping chambers are the
ventricles (little bellies)
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Vein – blood vessels carry blood to the heart
Artery – blood vessels carry blood away from
the heart
The atria receive blood from the veins while
the ventricles eject blood from the heart into
the arteries.
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Right atrium – receives blood from three
veins: superior vena cava, inferior vena cava,
and coronary sinus.
Right ventricle – sends deoxygenated blood
to the lungs for oxygenation
 Pulmonary circulation
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Left atrium – receives oxygenated blood from
the lungs
Left ventricle – the thickest chamber of the
heart and forms the apex of the heart. It
sends oxygenated blood to the body via the
aorta.
 Systemic circulation
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Each of the four valves helps to ensure the
one-way flow of blood by opening to let
blood through and then closing to prevent its
backflow.
As the walls of each chamber contract and
relax, resulting pressure differences across
the heart valves force valves to open and
close.
Atrioventricular valves (AV) are located between
the atrium and ventricle. There is a right and left
atrioventricular valve.
 The right atrioventricular valve is also known as
the tricuspid valve.
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 This valve has three flaps/cusps
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The left atrioventricular valve is also known as
the bicuspid valve or mitral valve
 This valve has two flaps/cusps
Semilunar Valves (SL) are located between the
ventricles and the arteries leaving the heart.
 (lunar = moon-shaped (because they are made up of
three crescent moon-shaped cusps)
 The pulmonary valve is known as the right semilunar
valve. Blood travels to the lungs via the pulmonary
valve into a large artery, the pulmonary trunk.
 The aortic valve is known as the left semilunar valve.
Blood travels into the systemic circulation via the
aortic valve into the large artery the aorta.
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Chordae tendineae are tendon like cords that
are connected to the valves.
The chordae tendineae are then connected to
cone-shaped trabeculae carneae called
papillary muscles.
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There are two closed circuits in which the
heart pumps blood.
There is the pulmonary circulation, carrying
blood to the air sacs (alveoli) of the lungs, and
the systemic circulation carrying blood to the
rest of the body.
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The right sides of the heart receives all of the
dark deoxygenated blood.
The left side of the heart receives the bright
red oxygen rich blood from the lungs.
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The right side of the heart receives blood via
three veins superior vena cava, inferior vena
cava, and the coronary sinus (vein).
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A vascular sinus is a thin-walled vein
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The pulmonary trunk artery leads
deoxygenated blood to the lungs.
The trunk branches out into the left and right
pulmonary artery.
 Note the color
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The right and left pulmonary trunk vein then
returns oxygenated blood into the left
atrium.
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The left ventricle of the heart then ejects
blood into the aorta.
The aorta then separates into smaller
systemic arteries.
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Three blood vessels branch out from the
aorta:
 Left common carotid artery
 Left subclavian artery
 Brachiocephalic trunk
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The coronary (cardiac) circulation is the flow
of blood through the many vessels that pierce
the myocardium.
The left and right coronary arteries branch
from the ascending aorta.
The left coronary artery divides into the
anterior interventricular and circumflex
branches
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The circumflex branch lies in the coronary
sulcus
 Left atrium, left ventricle
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The anterior interventricular branch lies in the
anterior interventricular sulcus
 Both ventricles
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The posterior interventricular branch lies in
the posterior interventricular sulcus
 Both ventricles
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Marginal branch extends beyond the
coronary sulcus and runs along the right
margin of the heart
 Right ventricle
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The coronary sinus carries most of the
deoxygenated blood from the myocardium. It
lies on the posterior surface of the heart.
It is divides into the great cardiac vein, middle
cardiac vein, small cardiac vein, anterior
cardiac veins
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The source of the electrical activity is a
network of specialized cardiac muscle fibers
called autorhythmic fibers.
They are self-excitable
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Sinoatrial (SA) node – is located in the right atrial wall
inferior to the opening of the superior vena cava
Atrioventricular (AV) node – located in the interatrial
septum just anterior to the opening of the coronary
sinus
Atrioventricular (AV) bundle (Bundle of His) – this is
the only site where action potentials can conduct
from the atria to the ventricles.
Right and Left bundle branches – within the
interventricular septum
Purkinje fibers
Jenkins, Gail W., Christopher P. Kemnitz, and
Gerard J. Tortora. Anatomy and Physiology:
From Science to Life. Hoboken, NJ: Wiley,
2007. Print.
Morton, David A., K. Bo Foreman, and Kurt
H. Albertine. The Big Picture Gross
Anatomy. New York: McGraw Hill Medical,
2011. Web.