Ch 11: The Heart (Part 1)

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Ch 11 The Heart(Part 1)
Physiology of heart
Pumps blood and all of its contents respiratory
gases, nitrogenous wastes, plasma proteins,
nutrients, electrolytes, water in plasma, RBCs,
WBCs, platelets, and heat
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Anatomy
Located in mediastinum of thoracic cavity,
slightly to left of sternum
Surrounded and protected by rib cage, diaphragm
lungs
Size closed fist (less than 1lb)
Shape Triangular (Hollow cone)
Base (more broad, superior) Apex (pointed end,
inferior) tilted to the left hip
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Review
Serous Membrane around heart Pericardium
heart
Visceral pericardium
(Serous fluid for lubrication )
Parietal pericardium
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Heart membranes Heart wall
Epicardium- epithelial and connective attached
to pericardium, outermost
Myocardium- cardiac muscle for contraction, middle
Endocardium- endothelium (epithelial) forms
valves and chambers, innermost, very smooth for
easy blood flow
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Heart Chambers
(4 Total 2 ventricles and 2 atria)
2 ventricles discharge chambers, pump blood to
arteries (more muscular)
LV- pumps oxygen-rich blood out the aorta
(artery) to the body, most muscular
(thicker-walled) chamber
RV- pumps oxygen-poor blood out the pulmonary
trunk pulmonary arteries to the lungs (to get
oxygen)
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Heart Chambers
2 atria- receiving chambers, receive blood from
veins, (more elastic)
RA- receives oxygen-poor blood from the body (via
the superior and inferior vena cava), passes
blood to the right ventricle
LA- receives oxygen-rich blood from the lungs
(via the L R Pulmonary veins), passes blood
to the left ventricle
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External Heart (including chambers)
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Internal chambers
Thicker-walled ventricle!
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Septa
Interventricular septum separates RV and LV
Interatrial septum separates RA and LA
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4 Valves Help Prevent Backflow
2 AV valves each between an atrium and a
ventricle
1. Tricuspid valve 3 cusps, between RA and RV
2. Bicuspid (mitral) valve 2
cusps, between LA and LV
Chordae tendineae heart strings
attached to papillary muscles in ventricle,
prevent AV valves from swinging backwards
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Valves (the other 2)
2 Semilunar Valves- each is between a ventricle
and its respective artery
1. Aortic valve- 3 cusps, between LV and aorta
2. Pulmonary valve- 3 cusps, between RV and pulm.
Trunk (pulm artery)
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valves
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Great Vessels (assoc. with heart)
Aorta (Oxygen-rich) blood from LV ? body
Pulmonary Arteries/Pulmonary trunk (oxygen-poor)
blood from RV ? lungs
Pulmonary Veins (oxygen-rich) from lungs ? LA
Superior vena cava (SVC)- (oxygen-poor) blood
from upper body ? RA
Inferior vena cavs (IVC)- (oxygen-poor) blood
from lower body ? RA
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Great vessels
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Cardiac Circulation
FYI The heart is an organ and needs its own
supply of blood. Not only does the heart pump
blood to organs of the body it also pumps blood
to its own myocardium!
Cardiac Circulation circulation to from
myocardium (of the heart wall)
Coronary Arteries carry oxygenated blood from
aorta to myocardium of heart wall
Cardiac Veins drains deoxygenated blood from
myocardium to coronary sinus vein
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Cardiac Circulation
FYI - One special vein collects all the blood
from the cardiac veins!
Coronary Sinus Vein receives drainage from
cardiac veins, empties deoxygenated blood into
right atrium!
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Blood flow through the heart
Arteries carry blood away from heart, usually
oxygenated blood (except pulm. Arteries)
Veins blood toward heart, usually deoxygenated
blood (except pulm. Veins)
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Systemic vs Pulmonary Circulation
Pulmonary to and from lungs ( includes
pulmonary trunk, arteries, and veins)
Systemic to and from body (including aorta,
arteries, veins, and vena cava)
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Systemic vs Pulmonary Circulation
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Pathway of blood
RA
Tricuspid valve
RV
Pulm valve
IVC or SVC
Pulm. arteries
Body
Lungs
Aorta
Pulm. veins
Aortic valve
LV
LA
Bicuspid valve
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Video How the Heart Works?