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Lab 10
Blood and The Heart
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LAB 10
Blood and The Heart
Learning Objectives
•
Differentiate between red and white blood cells and describe the role of each
•
Describe the anatomy of the heart
•
Explain how blood travels through the heart
•
Describe how electricity is conducted through the heart
INTRODUCTION
All cells and organ systems in the human body require nutrients and oxygen. They
must also eliminate waste products as they accumulate. The circulatory and respiratory systems play a major role in these processes.
The circulatory system is driven by the heart (Figure 1), a muscular pump that moves
blood through the network of arteries, arterioles, capillaries, venules, and veins of the
body. It is a closed system in which blood remains in the vessels (arteries and veins),
and does not flow freely in organs. This mechanism allows the delivery of nutrients
and oxygen to all cells in the body, and also allows for waste removal.
TYPES OF BLOOD CELLS
Figure 1: Illustration of the heart.
Blood is a fluid tissue. It serves three main functions:
• Transports oxygen, carbon dioxide, nutrients, hormones, heat, and waste.
• Regulates pH, body temperature, and water content of cells.
• Protects against blood loss through clotting and against disease via the action of white blood cells and antibodies.
Blood is composed of a variety of cells and cell fragments suspended in a liquid called plasma (Figure 2). Plasma comprises the
largest portion of blood, accounting for 55% of the fluid. Plasma itself is nearly 90% water. Table 1 lists the cell types found in
blood and their corresponding functions.
The most abundant blood cells are erythrocytes and lymphocytes.
Erythrocytes transport respiratory gases such as O2 and, to a lesser degree, CO2 (although most CO2 is dissolved in plasma) to and from the
lungs and cell. This exchange of gases and nutrients is known as respiration. Erythrocytes contain hemoglobin, an iron-containing protein,
which binds and carries these gases. It is hemoglobin that gives blood
its characteristic red color; however, it also turns to a purple-blue hue
when deoxygenated. This is why veins look purple.
Leukocytes are one component of the immune system, contributing to
the body’s defense system. They attack foreign microorganisms and
produce antibodies. Platelets mediate blood clotting, and also contribute to immune defense.
HEMATOPOIESIS
Figure 2: Red and white blood cells. The white blood cells are fighting a pathogen.
The adult human body contains five liters of blood, accounting for
nearly 8% of a person’s weight. It is formed through hematopoiesis
(Figure 3). Hematopoiesis produces blood cells in the red marrow of
long bones, flat bones, vertebrae, and the pelvis. Within the red bone
marrow, hematopoietic stem cells divide into various “blast” cells. Each
of these cells mature and becomes a specific type of blood cell.
Blood and The Heart
Table 1: Types of Blood Cells
Erythrocytes
Also known as red blood cells; comprise approximately 45% of blood;
contain hemoglobin for oxygen and carbon dioxide transport.
Lymphocytes
Involved in the immune response; produce antibodies.
Monocytes
Thrombocytes
Phagocytic macrophages.
Also known as platelets; involved in blood clotting.
Neutrophils
Key to wound healing.
Eosinophils
Phagocytosis.
Basophils
Leukocytes
Release histamines.
Comprise approximately 1% of blood; involved in fighting disease and
foreign objects in the body as part of the immune system. Monocytes,
neutrophils, eosinophils, and basophils are types of leukocytes.
Figure 3: Hematopoiesis sequence.
Blood and The Heart
BLOOD TYPE
There are four types of blood: A, B, AB, and O (Figure 4). Each is characterized by the glycoproteins and
lipoproteins embedded in the surface of red blood cells
(RBCs). In addition to type, blood can be rhesus (Rh)
factor positive or negative. These proteins are inherited
and may differ from individual to individual. If, during a
transfusion, an individual receives blood with the incorrect RBC proteins (for blood type or Rh factor), these
proteins may be recognized as antigens. In this case,
antibodies will be produced that bind to the antigens and
cause agglutination (clumping), leading to the destruction of the foreign RBCs.
ANATOMY OF THE HEART
Figure 4: ABO blood type diagram.
The heart pumps blood throughout the body. As the heart contracts and relaxes, it circulates blood through arteries, capillaries, and veins to every cell. The heart is located in the mediastinum, the cavity between the lungs, and is tilted so that the apex
(pointed end) points toward the left hip and the base (broad end) points toward the right shoulder. The heart is surrounded by
the pericardium, a sac with an outer fibrous layer that anchors the heart to the surrounding structure and an inner serous layer that consists of an outer parietal layer and inner visceral layer. A thick layer of serous fluid, called the pericardial fluid, lies
between these two layers to provide lubrication during heart contractions.
The muscular wall of the heart consists of three layers:
1. Epicardium – The visceral layer of the serous pericardium.
2. Myocardium – The muscular part of the heart, consisting of cardiac muscle and non-contracting Purkinje fibers that conduct nerve impulses.
3. Endocardium – The thin, smooth endothelial inner lining of the heart, which is continuous with the inner lining of the
blood vessels.
As blood travels through the heart, it passes through four chambers regulated by four valves (Figure 5). The two upper chambers, the right and left atria, are separated longitudinally by the interarterial septum. The two lower chambers, the right and left
ventricles, are the pumping machines of the heart and are separated longitudinally by the interventricular septum. A valve follows each chamber and prevents the blood from flowing backward into the chamber from which the blood originated. Two prominent grooves, the coronary sulcus and the anterior interventricular sulcus, are visible on the surface of the heart.
BLOOD PATHWAYS
Deoxygenated blood from the systemic circulation
enters the right atrium through three veins: the superior vena cava, the inferior vena cava, and the coronary
sinus. Blood is temporarily stored in the right atrium,
located in the upper-right side of the heart, as well as
the right auricle. During the interval when the ventricles
are not contracting, blood passes down through the
right atrioventricular (AV) valve into the next chamber,
the right ventricle. The AV valve is also called the tricuspid valve because it consists of three flexible cusps,
or flaps.
Figure 5: The anatomy of the heart.
The right ventricle pumps blood to the lungs. The right
ventricle has thicker and more muscular walls than
the right atrium, which are used to generate a forceful
contraction that pumps blood through the three-cusped
pulmonary semilunar valve and into the pulmonary
trunk. The pulmonary trunk branches into two pulmonary arteries, leading to the right and left lungs. When
the right ventricle contracts, the right AV valve closes
and prevents blood from moving back into the right
atrium. Chordae tendineae are attached to papillary
Blood and The Heart
muscle on the opposite bottom side of the ventricle to restrict AV valve
movement. In contrast, when the right ventricle relaxes, the initial backflow of blood into the pulmonary artery closes the pulmonary semi-lunar
valve and prevents the return of blood to the right ventricle.
The left atrium and left auricle receive oxygenated blood from the lungs
through the pulmonary veins. Like the right atrium, it is a reservoir for
blood awaiting movement into the left ventricle. When the ventricles relax, blood leaves the atrium and passes through the left AV valve into the
left ventricle. The left AV valve is also called the mitral valve or bicuspid
valve, and is the only heart valve with two leaflets.
The left ventricle is the pumping chamber for systemic circulation. BeFigure 6: An electrocardiograph of a typical heartbeat.
cause a greater blood pressure is required to pump blood through the
much more extensive systemic circulation, there is more muscle in the left ventricle than the right ventricle. This results in the
left ventricle being larger than the right ventricle. When the left ventricle contracts, it pumps oxygenated blood through the aortic
semilunar valve into the aorta. From there, blood can travel throughout the body.
It is important to note that, when the left ventricle contracts, the left AV valve closes and prevents blood from moving back into
the right atrium. Similar to the right AV valve, the chordae tendineae prevent hyperextension of the left AV valve. When the left
ventricle relaxes, the initial backflow of blood in the aorta closes the aortic semilunar valve, preventing the return of blood to the
left ventricle.
The heart sounds associated with the beating of the heart can be heard by listening to the thorax with a stethoscope. While
many people assume that this sound is the result of the physical heart contractions, it actually originates from blood turbulence
generated by the rhythmic opening and closing of two pairs of heart valves. The mitral and tricuspid heart valves cause the “lub”
sound as they close, preventing blood from flowing from the ventricles back into the atria. The corresponding “dub” sound occurs when the aortic and pulmonary valves close after blood exits the left ventricle and leaves the heart. Abnormal heart sounds,
called murmurs, are usually caused by improperly functioning valves.
ELECTRICAL CONDUCTANCE IN THE HEART
The microscopic anatomy of cardiac muscle cells allows them to be electrically excitable. Unlike skeletal muscle cells, cardiac
muscle fibers are linked by intercalated discs, areas where the plasma membranes overlap. Within the intercalated discs, the
adjacent cells are structurally connected physically by desmosomes, tight seals that connect the plasma membranes together.
They are also electrically coupled by gap junctions, ionic channels that allow for the transmission of a depolarization event. As
a result, the entire myocardium functions as a single unit with a single contraction of the atria followed by a single contraction of
the ventricles. This contraction originates in autorhythmic cells. These highly specialized cells are able to automatically generate an action potential without input from a nerve cell. These cells serve as the natural pacemaker for the heart, generating the
rhythmic contraction known as the heartbeat.
Willem Einthoven received the Nobel Prize in Physiology and Medicine in 1924 for his work that led to the discovery of the electrocardiogram. This test detects the electrical activity of the heart and provides useful clinical information regarding the strength
and frequency of the heart’s contractions. The typical graph generated
from an electrocardiogram has characteristic P, Q, R, S, and T waves that
correspond to the depolarizing events of the cardiac cycle. The electrical
currents generated by the contraction of the heart muscle can be monitored through 12 electrodes placed strategically on the body and an electrocardiograph. Figure 6 shows the distinctive pattern of a typical electrocardiogram. The P wave is a small wave that represents the depolarization
of the atria. During this wave, the muscles of the atria are contracting. The
QRS complex is a rapid down-up-down movement. The upward movement produces a tall peak, indicated by R. The QRS complex represents
depolarization of the ventricles. The T wave represents the repolarization
of the ventricle. Electrical activity generated by the repolarization of the
atria is concealed by the QRS complex.
Figure 7: Electrical conduction of the heart is controlled by the
SA node, the AV node, and the bundle of His.
Physiologically, this is accomplished through the electrically excitable cells
and special nodes that initiate those signals. The sinoatrial (SA) node,
located in the upper wall of the right atrium, initiates the cardiac cycle by
generating an action potential that spreads through both atria via the gap
junctions of the cardiac muscle fibers (Figure 7). The atrioventricular (AV)
node, located near the lower region of the interatrial septum, receives the
action potential generated by the SA node. The electrical transmission is
Blood and The Heart
slightly delayed here, allowing the atria to fully contract before the action potential is passed on to the ventricles. The AV bundle
(bundle of His) receives the action potential from the AV node and transmits the impulse to the ventricles via the right and left
bundle branches. Except for the AV bundle, which provides the only electrical connection, the atria are electrically insulated from
the ventricles. The Purkinje fibers are large-diameter fibers that conduct the action potential from the interventricular septum,
down the apex, and then upward through the ventricles. These mechanics allow the heart to beat more than two billion times
during a person’s lifetime, providing the nutrients that cells need to exist on a daily basis.
Did You
?
Know
Complete blood count, or CBC, tests are one of the first procedures taken when working with
healthcare patients. CBCs provide a quick, yet comprehensive, assessment of a patient’s
health by measuring a glossary of blood constituents such as red blood cell levels, white blood
cell levels, and platelet levels. It also checks hemoglobin levels, which indicate the amount of
oxygen carrying proteins present in the blood, and hematocrit levels, which indicate the ratio
of red blood cells to plasma in the blood.
Experiment 1
Introduction to Science
Lab 10
Heart Valves and Pumps
Experiment Inventory
Materials
(2) Balloons (Only 1 balloon is required; an extra is provided in case the first balloon is compromised during the procedure)
(1) Canning Jar
(2) Straws
(1) Skewer
(1) Ruler
(1) Waste Beaker (any volume)
Tape
*Scissors
*Water
*You must provide
EXPERIMENT 1: HEART VALVES AND PUMPS
The heart beats an average of 100,000 times and pumps approximately 7,571 liters of blood through its chambers daily. This is
made possible by the intricate network of vascular pathways, arterial canals, and heart valves. This architecture is coupled to the
heart’s electrochemical pumping system and a nest of cardiac muscle that contracts to pump blood toward the lungs and other
organs.
Heart valves are flexible membranes that influence the directionality of blood through the heart. They expand when fluid is present and collapse when fluid departs. This dynamism prevents blood from retracing its route. In this experiment, you will explore the
function of the heart valves and their role in pumping blood.
PROCEDURE
1. Use scissors to cut off the neck of the balloon. Remove almost 100% of the neck, but do not remove the main, circular section of the balloon. Set the balloon and neck aside.
2. Fill the canning jar with water until it is approximately halfway full.
3. Fasten the circular section of the balloon around the top of the jar. The goal is to create a tight seal.
4. Use the skewer to poke two small holes in the balloon on the jar. These holes should be approximately 2.0 cm apart from
each other.
5. Position one straw in each hole. This should create a tight fit and should not compromise the sealed environment.
Note: It is important that the holes the straws are inserted into are not so large that air can pass through the
holes outside of the straw canal. If the holes are too large, repeat Steps 1 – 5 with the second balloon.
6. Rotate the end of one of the exposed straws by pulling on the accordion folds at the top of the straw and pressing down.
7. Retrieve the balloon neck (cut off in Step 1). Position the neck over the down-pointing straw.
8. Tape the neck to the straw to seal the connection. The neck should hang limp, forming a flap on the top of the straw. This
constitutes your “valve.”
9. Position the waste beaker (any volume) beneath the valve.
10.Use your index finger to press on the balloon stretched over the jar. Continue to press and release the balloon until water
moves through the straws. Record what happens in Table 2. If possible, record the amount of water that is displaced into the
waste beaker.
11.Remove the tap and neck from the straw, and pour out the water from the waste beaker.
12.Remove the balloon neck and repeat Step 10. Record what happens in Table 2.
Data Sheet
Lab 10
Experiment 1 Data Sheet
Table 2: Experimental Observations
Observations (with valve) and mL
H2O Displaced?
Observations (without valve) and mL H2O
Displaced?
Experiment 2
Introduction to Science
Lab 10
Effect of Chelation Therapy on Arterial Plaque Levels
Experiment Inventory
Materials
Labware
(1) Bottle of 4% EDTA Solution
(3) 250 mL Beakers
(1) Bottle of 8% EDTA Solution
(1) 100 mL Graduated Cylinder
(1) Permanent Marker
*Water
*(2) Uncooked Eggs
*You must provide
EXPERIMENT 2: EFFECT OF CHELATION THERAPY ON ARTERIAL PLAQUE LEVELS
Chelation is a widely accepted treatment to remove heavy metals from the human body. Chelation therapy relies on a chelating
agent such as ethylenediaminetetraacetic acid (EDTA) to bind and remove heavy metals from a surface.
Chelation therapy has been used to treat lead poisoning, and evidence suggests that additional health concerns could also be
treated with chelation therapy. For example, atherosclerosis, an arterial disease that causes white blood cell and low-density lipoprotein deposits on the interior surface of arteries, may be minimized through chelation therapy. Studies using chelation therapy to
treat psoriasis, Alzheimer’s disease, angina, and other diseases have also shown positive results. However, these reports are less
definitive, and further research is needed to draw widespread conclusions. In this experiment, you will observe the effect of EDTA
on eggshells and draw conclusions about the efficacy of chelation therapy as an atherosclerosis treatment.
Note: The EDTA provided in your kit should not under any circumstances be consumed. Gloves should be
worn when working with eggshells. Wash hands and all labware with warm, soapy water when finished with
the experiment.
PROCEDURE
1. Label three 250 mL beakers 1, 2, and 3 with the permanent marker.
2. Use the 100 mL graduated cylinder to measure and pour approximately 150 mL of water into Beaker 3.
3. Carefully pour all of the 4% EDTA solution into Beaker 1.
4. Carefully pour all of the 8% EDTA solution into Beaker 2.
5. Standing over a sink or trash receptacle, carefully crack each uncooked egg in half to create four equally sized domeshaped pieces. Rinse the yolk and egg whites down the drain with running water. Discard one piece of eggshell in the trash;
you will need only three for this experiment.
6. Gently rinse the eggshells in warm water, being careful not to break the shell. Place one shell into Beaker 1, Beaker 2, and
Beaker 3 with the dome side down.
Note: It is best to fill each dome with EDTA or water. This will cause the eggshell to sink toward the bottom of
the beaker, rather than float at the top, and will create greater solution coverage.
7. Observe the eggshells over the next 7 – 14 days. Record daily observations of the shells in Table 3.
8. Dispose of all eggshells in the trash when you have completed the experiment.
Data Sheet
Lab 10
Experiment 2 Data Sheet
Table 3: Eggshell Observations
Beaker 1 Observations
(4% EDTA Solution)
Day
Beaker 2 Observations
(8% EDTA Solution)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Beaker 3 Observations
(Pure H2O)
Experiment 3
Introduction to Science
Lab 10
Microscopic Anatomy of Blood
Experiment Inventory
Materials
Sickle Cell Digital Slide Images
Blood Cell Digital Slide Images
EXPERIMENT 3: MICROSCOPIC ANATOMY OF BLOOD
In this experiment you will visualize the microscopic anatomy of blood cells to better understand the blood.
PROCEDURE
1. Observe the following digital slide images. Then, answer the post-lab questions.
Figure 8: Red blood cells, 1000x. Red blood cells (RBCs) are typically circular in shape. Individuals with sickle cell anemia produce blood cells
with atypical cell shapes. These tend to appear elongated or suckered near the middle of the cell.
Figure 9: Sickle cell blood, 1000x. Note that the normal and atypically shaped red blood cells are intermingled. Sickled blood cells can clog the
capillaries and cause a blood flow crisis.
Figure 10: Blood smear, 1000x. Blood cell types shown include erythrocytes (red blood cells), lymphocytes (the sparse, large, pale pink
circles), and neutrophils.
Experiment 4
Introduction to Science
Lab 10
Blood Typing Experiment
Experiment Inventory
Materials
Labware
(1) Permanent Marker
(1) 12-Well Plate
Blood Sample A
Blood Sample B
Blood Sample C
Anti-A Serum
Anti-B Serum
Anti-Rh Serum
(9) Toothpicks
EXPERIMENT 4: BLOOD TYPING EXPERIMENT
Blood typing is an important part of medicine. Antigens, which are specific glycoproteins on the surface of red blood cells, can
agglomerate when a foreign antibody is present in the circulatory system. Agglutination can occur when multiple blood types are
mixed if RBCs with different antigens are in the same environment because their respective antibodies will react to the foreign antigens. In this experiment, you will view this reaction by mixing simulated blood samples and antibodies. Agglutination will occur if
the antibody and corresponding foreign antigen are mixed.
PROCEDURE
1. Use the permanent marker and Figure 11 to label the 12-well plate. The fourth column (on the far right side of the plate) will
not be used in this experiment.
2. Place one drop of anti-A serum in wells A1 – A3.
3. Place one drop of anti-B serum in wells B1 – B3.
4. Place one drop of anti-RH serum in wells C1 – C3.
5. Place one drop of blood sample A into wells A1, B1, and C1.
6. Place one drop of blood sample B into wells A2, B2, and C2.
7. Place one drop of blood sample C into wells A3, B3, and C3.
Figure 11: Labeling diagram for the 12-well plate.
8. Use a clean toothpick to mix the blood sample and typing sera in each well.
9. Wait 2 minutes. Then, observe each well for agglutination, which indicates a positive result. Note that agglutination will be
observable as a precipitate when working with simulated blood samples.
10.Record your observations in Table 4. Determine the blood type of each sample based on the results.
Data Sheet
Lab 10
Experiment 4 Data Sheet
Table 4: Blood Typing Results
A
(Blood Sample A)
1 (Anti-A Serum)
2 (Anti-B Serum)
3 (Anti-Rh Serum)
Blood Type
B
(Blood Sample B)
C
(Blood Sample C)
Experiment 5
Introduction to Science
Lab 10
Virtual Model - The Heart
Experiment Inventory
Materials
Virtual Model
*Internet Access
*Computer Access
*You must provide
EXPERIMENT 5: VIRTUAL MODEL - THE HEART
The heart is located in the mediastinum, a cavity located between the lungs. The primary function of the heart is to accept deoxygenated blood from the body, pump this blood toward the lungs for oxygenation, and deliver the oxygenated blood back out of the
heart to be circulated throughout the body. In this experiment, you will use the virtual model to better understand the structure of
the heart.
PROCEDURE
1. Open the virtual model website .
2. Familiarize yourself with the virtual model. Navigate the model by using the commands below:
a. Select the body system of interest from the box in the lower left-hand corner of the model. Note that some body systems may have multiple options for viewing (e.g., for the nervous system, you can select either the general
anatomy or the brain).
b. Hover your cursor over different areas on the model to display labeled terms.
c. Click on any component of the body to view a description of its function.
d. In the upper left-hand corner of the model, you will see a box containing an overview of the system you are currently viewing (Figure 17). As you zoom in and out, a box will appear over the system overview showing you what
portion of the model is on your screen.
e. To the right of the system overview, you will see a vertical line with a “+” at the top and a “–“ at the bottom. Click
and drag the button on this line to zoom in and out of the virtual model.
f. When zoomed in, there are three ways to navigate to areas of interest:
• Use your cursor to click and drag the virtual model to the area of interest.
• Use your cursor to click on the box in the system overview of the left-hand side of the screen. Then, drag the
box to the area of interest.
• Click on the four arrows to the right of the system overview. These arrows will allow you to move up, down,
right, or left.
Figure 12: How to navigate the virtual model.
g. Below the system overview, there are five buttons that will allow you to change the orientation of the virtual mo el.
From left to right, these buttons will allow for an anterior view, posterior view, lateral view, superior view, and inferior view of the virtual model. Note that not all options may be available for each system.
h. Some systems may have multiple layers to explore. When this occurs, the word “Depth” will appear below the orientation buttons. Click on the word “Depth” to access a deeper layer of the system of interest.
i. To view multiple layers at once or to view two different systems at once, click the “Interactive Navigation” button to
the left of the system overview. Note that this option is not available for every system or for every orientation of a
system. You will see a box appear over half of the virtual model. When the box appears, you will see several options within the top bar:
• The hand button will allow you to move the box to any location on the virtual model.
• The “Menu” option will allow you to pick a second system to overlay on the virtual model.
• The “Depth” button will appear if a system has multiple layers that can be observed.
• The “Transparency” button will allow you to alter the transparency of the two systems you are viewing. Move
the button to the bottom to see only the system of interest. Move the bottom to the top to see only the second system.
• The button containing two boxes will create a smaller box for you to move around the screen.
• The “X” button will allow you to stop the Interactive Navigation.
• To resize the Interactive Navigation box, click the button in the lower right hand corner and drag it to create
the desired size.
3. After you are comfortable with the Virtual Model interface, select the Cardiovascular System. Then select the Heart.
4. Click through the heart.
Note: Zoom in on the heart to reveal all elements. Some components are only
visible when you zoom in. Remember that you will need to reorient the virtual
model to observe the entirety of the heart.
5. Hover the cursor over different components to view the name. Click on each component to
view a description of it.
Hint: Review the post-lab questions as you work through the heart.
Figure 13: Work your way through
the heart to better understand its
anatomical placement and func-
6. Click the “Depth” button to view the second layer of the heart. Note that the second layer can
tion.
only be seen when the virtual model is in the anterior view (Figure 13).
7. As you move through the model, take a screenshot or use your cell phone to take a picture of the heart components listed
below. Submit these images to your instructor along with your post-lab questions.
a. Myocardium
b. Mitral Valve
Hint: Be sure to hover your mouse over the heart component to reveal its label in the image.
15.Once you have completed your overview of the heart, complete the post-lab questions.
Experiment 6
Introduction to Science
Lab 10
Sheep Heart Dissection
Experiment Inventory
Materials
Sheep Heart
Dissection Tool Kit
Dissection Tray
EXPERIMENT 6: SHEET HEART DISSECTION
Sheep hearts share structural and functional characteristics with human hearts. In this activity, you will explore the anatomy of the
sheep heart to identify major heart features.
PROCEDURE
1. To begin, lay down your underpad and place your dissecting tray on top of it. Be sure you have all of your safety equipment
on before beginning.
2. Once prepared, gently open the bag your sheep heart is in.
3. Lay your sheep heart onto the dissecting tray.
4. Examine the anterior surface of the heart. Identify the following structures:
• Pericardium
• Epicardium
• Base
• Apex
• Right Auricle
• Left Auricle
• Right Ventricle
• Left Ventricle
• Pulmonary Trunk
5. Examine the posterior surface of the heart. Identify the following structures:
• Coronary Sulcus
• Left Auricle
• Left Ventricle
• Right Auricle
• Right Ventricle
6. Insert a blunt probe into the collapsed superior vena cava and into the right atrium. Find the opening for the inferior vena
cava, and push the probe into this vessel.
7. Make a coronal cut in the sheep heart with a scalpel. Start at the apex and cut toward the base, slicing through both auricles, but not all the way through the base (do not completely separate the two halves).
8. Identify the following internal structures:
• Myocardium
• Endocardium
• Right Atrium
• Right Auricle
• Pectinate Muscle
• Opening of the Superior and Inferior Vena Cava
• Tricuspid Valve
• Opening of the Coronary Sinus
• Right Ventricle
• Chordae Tendineae
• Papillary Muscles
• Pulmonary Semilunar Valve
9. Insert a blunt probe into the right atrium, and find the opening of the coronary sinus (this will be inferior to the opening of the
inferior vena cava). Insert the probe into this region, and observe its movement.
10.While still in the right atrium, use the blunt probe to explore the pulmonary trunk, pushing the probe to the superior end of
the vessel.
11.Remove the probe, and make a longitudinal incision across the pulmonary trunk with a scalpel. This will expose the pulmonary semilunar valve.
12.Identify the following structures on the left side of the heart:
• Left Atrium
• Left Auricle
• Bicuspid Valve
• Left Ventricle
• Aortic Semilunar Valve
• Aorta
13.Observe the heart valves and note if there are chordae tendineae or papillary muscles.
14.Identify the openings to the right and left coronary arteries, just anterior to the flaps of the aortic valve.
15.Upon completing the sheep heart dissection, clean off your dissecting tray and dissecting tools with soap and water. Biological scraps should not be thrown into the garbage. Securely store the biological scraps until the end of the term so that they
can be properly disposed of at one time.
16.Clean the area in which you worked with soap and water. As long as the underpad has not been damaged, keep it for future
experiments.