Transcript HEART DISSECTION LAB

HEART
DISSECTION
LAB
Procedure
1. Obtain a dissection pan and
dissecting kit.
Procedure
2. Obtain a heart
and rinse off
the excess
preservative
with tap water.
Pat the heart
dry.
3. Place the heart in a
dissection pan.
4.Observe the pericardium. If the
pericardial sac is intact then remove
the outer layer from its attachment
points.
5. Carefully pull the visceral
pericardium (epicardium)
away from the myocardium
6. Examine the
external surface
of the heart. Notice
the accumulation of
adipose tissue.
This adipose
usually accumulates
along the
boundaries of the
heart chambers and
along the coronary arteries.
Remove as much adipose as possible.
7. Now you should be
able to identify the
apex (bottom left
"point" of the heart)
and the auricles
(earlike flaps
projecting from the
atria).
8. Locate the pulmonary
trunk and the aorta on
the superior aspect of
the heart. Clear the
adipose away from
these arteries. The
pulmonary trunk
divides into the left
and right pulmonary
arteries. The aorta will
have a large branch
coming from beneath
the pulmonary trunk.
9. Starting at
the apex
and moving
towards the
base, …….
9. Make a
coronal
(frontal) cut
through the
heart. Stop
cutting when
your knife
reaches the
top portions of
the atria.
10.Notice that the heart is made up of
three histological layers: the
epicardium, the myocardium and the
endocardium
11.Locate the
side with the
thickest
myocardial
wall. This will
orient you to
the left side of
the heart
12.You should see
that there are
spaces (or
"chambers") on
the left and right
sides of the
lower heart.
These are the
left and right
ventricles
13.You should also
see a thick
structure dividing
the two
ventricles, the
bulk of which is
comprised of
cardiac muscle.
This is the
interventricular
septum.
14.The ventricles are divided from the
chambers directly above them by
atrioventricular (or "AV") valves.
These valves have flaps (or "cusps")
to which "heart strings" attach.
14.The left AV valve
has two cusps, so
it can be referred
to as being a
"bicuspid" valve.
The right valve
has three cusps,
so it can be
referred to as
being a
"tricuspid" valve.
15.The strings that
attach to the AV
cusps are called
chordae
tendinea.
16.The chordae tendineae are
anchored to the ventricular walls
via papillary ("nipple-like")
muscles.
17.Remove the right ventricular wall
and cut into the pulmonary trunk
in order to view the pulmonary
semilunar valve.
18.Remove
the left
ventricular
wall and cut
into the
aortic trunk
in order to
view the
aortic
semilunar
valve.
ANTERIOR
VIEW
ANTERIOR
VIEW
ANTERIOR
VIEW
POSTERIOR
VIEW
POSTERIOR
VIEW
LAYERS OF
THE HEART
WALL
LAYERS OF
THE HEART
WALL
1) Adipose
Tissue
2) Myocardium
of the
Interventricular
Septum
3) Myocardium
of the Left
Ventricular
Wall
4) Right Ventricle
(the space below
the right A.V.
valve)
5) Left Atrium (the
space above the
left A.V. valve)
6) Left Ventricle
(the space below
the left A.V. valve)
7) Aortic Valve (or
left semilunar valve)
8) Left
Atrioventricular
(AV) Valve (which
has two flaps, or is
"bicuspid";
sometimes also
called the mitral
valve)
9) Apex (point) of
the Heart
10) Ascending Aorta
(the tube above the
aortic valve)
11) Left Atrium (the
space above the left
A.V. valve)
12) Chordae Tendineae
(the "heart strings" that
run from the cusps of
the A.V. valves to the
papillary muscles)
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