HEART STRUCTURE
Location: Anterior Mediastinum
Visceral pericardium
cardiac notch
diaphragm
parietal pleura
Location: Anterior Mediastinum
Parietal pericardium
Right Side: Pulmonary Circuit
Left Side: Systemic Circuit
• Deoxygneated blood returned
• Oxygenated blood distributed
Layers
• Outer Epicardium
• Middle Myocardium
• Inner Endocardium
Epicardium - Outermost layer
Myocardium - Middle layer
endocardium - Inner layer
ANTERIOR EXTERNAL STRUCTURES
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D
E
C
F
B
A
A
B
C
D
H
E
A
F
G
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Flow Through the Heart: Annotated
RIGHT ATIRUM
deoxygneated blood enters the RIGHT ATRIUM from
the SUPERIOR and INFERIOR VENA CAVAE
Anatomical features:
• contains thin walls with very little muscle
• contains pectinate muscles
• on medial wall a small opening called the CORONARY
SINUS that serves to drain the CORONARY VEINS
Passively and through atrial contraction blood will move
into the RIGHT VENTRICLE after passing through the
TRICUSPID VALVES
Between the atria and ventricles there are ATRIOVENTRICULAR VALVES
RIGHT ATIRUM
Pectinate Muscle
Flow Through the Heart: Annotated
RIGHT VENTRICLE
blood passes from the RIGHT ATRIUM through the
TRICUSPID VALVES into the RIGHT VENTRICLE
The inferior aspect of the three cusps of the valves are
connected to a series of long tendinous structures called the
CHORDAE TENDINEAE.
These in turn are anchored and attached to muscles in the
ventricular walls called the PAPILLARY MUSCLES.
The chordae tendineae and the papillary muscles
PREVENT the tricuspid valves from everting during
ventricular contraction and ensure that the blood does not
move backwards
Flow Through the Heart: Annotated
RIGHT VENTRICLE
The walls of the right ventricle are THIN, since this chamber
will pump blood, under pressure, to the lungs
The myocardial walls are perforated with small columns of
muscle called the TRABECULAE CARNEAE. Their function
is to increase ventricular surface area and to PREVENT
suction during contraction
Flow Through the Heart: Annotated
RIGHT VENTRICLE
One additional structure in the right ventricular chamber is
the presence of the MODERATOR BAND.
This structure prevents overdistention of the ventricle during
contraction
Another function of the moderator band is connected to the
electrical conduction system of the heart
Flow Through the Heart: Annotated
RIGHT VENTRICLE
During ventricular contraction
the tricuspid valve is closed and
anchored by the chordae
tendineae and papillary
muscles.
Blood is then forced out under
pressure through the
PULMONARY SEMILUNAR
VALVES
These valves contain no
chordae or papillary muscles
but function with a reverse
vacuum effect.
Blood passing through the
pulmonary semilunar valves
enters the PULMONARY
TRUNK to the PULMONARY
ARTERIES to the lungs where
exchange of oxygen and carbon
dioxide occur
Flow Through the Heart: Annotated
Pulmonary Trunk
The PULMONARY TRUNK is used as a
landmark to identify the anterior aspect of the
heart
Terminology SNAFU:
We generally think of arteries carrying
oxygenated blood and veins carrying
deoxygenated blood.
What type of blood is the PULMONARY
TRUNK/ARTERIES CARRYING???
Foundation:
Vessels leaving the heart are called arteries
vessels going towards the heart are called veins
regardless of the type of blood
Flow Through the Heart: Annotated
LEFT ATRIUM & VENTRICLE
A
Blood returns from the lungs via 4 PULMONARY VEINS - 2
from the right; 2 from the left. There are 4 portals entering
into the LEFT ATRIUM
Structurally the LA is similar to the Right Atrium, except the
walls are a little thicker.
The LA contains PECTINATE MUSCLES (A)
The left atrium DOES NOT contain a coronary sinus
Blood in the LA will passively and actively move into the
LEFT VENTRICLE before and during atrial contraction.
In doing so the blood will pass through the BICUSPID or
MITRAL VALVES - so named because it contains 2 cusps
The BICUSPID VALVE like the tricuspid valve is anchored by
chordae tendineae and HUGE papillary muscles in the
ventricular chamber, and is also endowed with
TRABECULAE CARNEAE
Flow Through the Heart: Annotated
LEFT ATRIUM & VENTRICLE
The OUTER left ventricular wall is VERY thick compared to
the right ventricle. This is becuase the LV will pump blood
out to the body, whereas the RV pumpped blood to the lungs
- rightly at the same plane as the heart.
The force of contraction in the LV is about 4x - 5x greater
than the RV
When the LV contracts blood is forced out through the
AORTIC SEMILUNAR VALVE. This valve is similar in
construction to the pulmonary semilunar valve.
Blood passing through the valve will move into the elastic
ASCENDING AORTA to the AORTIC ARCH and then be
distributed throughout the body
CHAMBER DIFFERENCES
IDENTIFY
A
D
B
C
A
interventricular septum
B
Ascending aorta
C
right ventricle
D
Mitral valve
CHAMBER DIFFERENCES
D
IDENTIFY
A
E
B
C
A
Ascending Aorta
B
right ventricle
C
left ventricle
D
E
pulmonary trunk
interventricular septum
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