Transcript Ch 11 Heart Anatomy and Circulation

Pages 356-363
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Includes the heart and the blood vessels
Functions:
◦ Deliver oxygen/nutrients to cells/tissues
◦ Remove carbon dioxide/waste products
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Blood is the transport vehicle
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Location
◦ Thoracic cavity
◦ between the lungs within the inferior mediastinum
(the central chamber of the thorax)
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Orientation
◦ Pointed apex directed toward left hip
◦ Base points toward right shoulder
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About the size of a human fist
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Superior
vena cava
Aorta
Pulmonary
trunk
Left lung
Pericardium
(cut)
Diaphragm
(a)
Apex of
heart
Midsternal line
2nd rib
Sternum
Diaphragm
(b)
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The heart is enclosed by the pericardium
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Pericardium—a double-walled (2 layered) sac
◦ Fibrous pericardium is loose and superficial
◦ Serous membrane is deep to the fibrous pericardium and
composed of two layers:
1. Parietal pericardium: outside layer that lines the inner
surface of the fibrous pericardium
2. Visceral pericardium: lies directly on heart; also known as the
epicardium
◦ Serous fluid fills the space between the layers of pericardium
 lubricates; prevents friction from the beating heart
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Pulmonary
trunk
Pericardium
Myocardium
Fibrous pericardium
Parietal layer of
serous pericardium
Pericardial cavity
Epicardium
(visceral layer
of serous
pericardium)
Heart
wall
Myocardium
Endocardium
Heart chamber
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Three layers comprise the walls of the heart:
1. Epicardium
 Most superficial; connective tissue
 (This is the visceral pericardium)
2. Myocardium
 Middle layer- the one that contracts
 Mostly cardiac muscle
 Desmosomes hold cells together
 gap junctions allow electrical wave to flow cell to cell
3. Endocardium
 Inner layer known as endothelium
 Endothelial cells are a layer of thin squamous cells with
vascularity
 A specialized type of epithelial cell
© 2015 Pearson Education, Inc.
Pulmonary
trunk
Pericardium
Myocardium
Fibrous pericardium
Parietal layer of
serous pericardium
Pericardial cavity
Epicardium
(visceral layer
of serous
pericardium)
Heart
wall
Myocardium
Endocardium
Heart chamber
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Right and left side are separate pumps
Four chambers:
 Atria -right and left (on top)
 Receiving chambers
 Ventricles -right and left (on bottom)
 Discharging chambers
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Left atrium
Right atrium
Right ventricle
(b) Frontal section showing interior chambers and valves.
Left ventricle
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Interventricular septum
◦ Separates the two ventricles
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Interatrial septum
◦ Separates the two atria
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Superior vena cava
Aorta
Left pulmonary artery
Right pulmonary
artery
Left atrium
Right atrium
Left pulmonary veins
Right pulmonary
veins
Fossa ovalis
Right atrioventricular
valve (tricuspid valve)
Right ventricle
Chordae tendineae
Pulmonary semilunar
valve
Left atrioventricular
valve (bicuspid valve)
Aortic semilunar valve
Left ventricle
Interventricular septum
Inferior vena cava
Myocardium
(b) Frontal section showing interior chambers and valves.
Visceral pericardium
(epicardium)
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Oxygen-poor blood flows from the right side
of the heart to the lungs
Oxygen-rich blood returns to the left side of
the heart from the lungs
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Oxygen-rich blood flows from the left side of
the heart (via the aorta) to body tissues
(oxygen is used at the cellular level; carbon
dioxide is returned to circulation via veins for
elimination from the body)
Oxygen-poor blood returns to the right side
of the heart via the superior vena cava
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Capillary beds
of lungs where
gas exchange
occurs
Pulmonary Circuit
Pulmonary
arteries
Pulmonary veins
Aorta and branches
Venae cavae
Left
atrium
Right
atrium
Left
ventricle
Heart
Right
ventricle
Systemic Circuit
KEY:
Oxygen-rich, CO2-poor blood
Oxygen-poor, CO2-rich blood
Capillary beds
of all body tissues
where gas exchange
occurs
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Four valves:
◦ Atrioventricular (AV) valves—between atria and
ventricles
 Bicuspid (mitral) valve (left side of heart)
 Tricuspid valve (right side of heart)
◦ Semilunar valves—between ventricle and artery
 Pulmonary semilunar valve
 Aortic semilunar valve
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Allow for unidirectional flow; prevent
backflow
Open/close in response to pressure
changes in heart
Leaky valves are ok… to a degree
 Valves that cannot close correctly cannot prevent
backflow
 Valves that are damaged (due to infection)
require more forceful contraction
 This leads to a weak heart and potential heart failure
This link shows a summary of the process of blood flow:
 http://highered.mheducation.com/sites/0072495855/student_vi
ew0/chapter22/animation__the_cardiac_cycle__quiz_2_.html
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This link shows a step by step process of flow:
http://www.sumanasinc.com/webcontent/anim
ations/content/humanheart.html
This link shows a valve replacement!! Very cool
https://www.youtube.com/watch?v=CsIdppyaPQ
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The heart has its own circulatory system
 Coronary arteries—branch from the aorta to supply
the heart muscle with oxygenated blood
 Cardiac veins—drain the myocardium of blood and
dump into the Coronary sinus (located posterior
and inferior)
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From the sinus, blood empties into the right
atrium and is returned to pulmonary
circulation for re-oxygenation at the lungs
© 2015 Pearson Education, Inc.
Superior vena cava
Right pulmonary artery
Aortic arch
Left pulmonary artery
Pulmonary trunk
Right pulmonary
veins
Left pulmonary veins
Left atrium
Right atrium
Right coronary artery
Anterior cardiac vein
Right ventricle
Left coronary artery
Left ventricle
Great cardiac vein
Small cardiac vein
Inferior vena cava
Apex