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Heart Dissection

Background:

The heart is a four-chambered, hollow organ composed primarily of cardiac muscle tissue. It is located

in the center of the chest in between the lungs. It is the main organ of the circulatory system. It contracts

rhythmically, pumping blood into the arteries. After passing through tissues, blood returns to the heart by way

of the veins. Cardiac muscle is a type of involuntary striated muscle found within the heart. Its function is to

pump blood through the circulatory system through muscular contraction.

In this lab you will be dissecting a preserved pig heart. Preserved pig hearts are the most commonly

dissected mammalian heart. The pig heart is very similar to a human heart, in that they both contain four

chambers, and are similar in size. Since the pig heart and the human heart are so alike, you will be dissecting the

pig heart in this dissection lab.

Objectives:

 Learn about the heart as an important organ in our body

 Examine a pig heart through hands-on dissection

 Learn the many different structures associated with the heart including both external and internal

structures

 Learn the functions of the different structures inside of the heart

Materials:

 One pig heart

 Dissection Tools

 Dissection tray

 Gloves

Procedure: EXTERNAL

1. Go to the bucket and get yourself a pig heart. Rinse off the excess preservative with tap water and run water

into the larger blood vessels to force any blood clots out of the heart chambers. Pat the heart dry and place it

in your dissection tray.

2. It is important to know that the heart is usually covered in adipose tissue. Your specimen may have arrived

with the adipose tissue already having been removed.

3. Before cutting into the heart, carefully observe the external heart. Locate the thin membrane or

pericardium that still covers the heart. The pericardium or pericardial sac, is a double layered closed sac

that surrounds the heart and anchors it. The pericardium consists of two tissues layers which are continuous

with each other where the vessels enter or leave the heart. The slender gap between the parietal & visceral

surfaces is the pericardial cavity & is filled with fluid to reduce friction between the layers as the heart

pumps.

4. After examining the pericardium, carefully remove this tissue. Located below the pericardium is the muscle

of your heart called the called the myocardium. Most of the myocardium is located in the lower two

chambers of the heart called ventricles.

5. Locate the tip of the heart or the apex. Only the left ventricle extends all the way to the apex.

6. Place the heart in the dissecting pan so that the front or ventral side is towards you (the major blood vessels

are on the top and the apex is down). The front of the heart is recognized by a groove that extends from the

right side of the broad end of the heart diagonally to a point above & to your left of the apex.

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Heart Dissection

Background:

The heart is a four-chambered, hollow organ composed primarily of cardiac muscle tissue. It is located in the center of the chest in between the lungs. It is the main organ of the circulatory system. It contracts rhythmically, pumping blood into the arteries. After passing through tissues, blood returns to the heart by way of the veins. Cardiac muscle is a type of involuntary striated muscle found within the heart. Its function is to pump blood through the circulatory system through muscular contraction. In this lab you will be dissecting a preserved pig heart. Preserved pig hearts are the most commonly dissected mammalian heart. The pig heart is very similar to a human heart, in that they both contain four chambers, and are similar in size. Since the pig heart and the human heart are so alike, you will be dissecting the pig heart in this dissection lab.

Objectives:

 Learn about the heart as an important organ in our body  Examine a pig heart through hands-on dissection  Learn the many different structures associated with the heart including both external and internal structures  Learn the functions of the different structures inside of the heart

Materials:

 One pig heart  Dissection Tools  Dissection tray  Gloves

Procedure: EXTERNAL

Go to the bucket and get yourself a pig heart. Rinse off the excess preservative with tap water and run water into the larger blood vessels to force any blood clots out of the heart chambers. Pat the heart dry and place it in your dissection tray.
It is important to know that the heart is usually covered in adipose tissue. Your specimen may have arrived with the adipose tissue already having been removed.
Before cutting into the heart, carefully observe the external heart. Locate the thin membrane or pericardium that still covers the heart. The pericardium or pericardial sac, is a double layered closed sac that surrounds the heart and anchors it. The pericardium consists of two tissues layers which are continuous with each other where the vessels enter or leave the heart. The slender gap between the parietal & visceral surfaces is the pericardial cavity & is filled with fluid to reduce friction between the layers as the heart pumps.
After examining the pericardium, carefully remove this tissue. Located below the pericardium is the muscle of your heart called the called the myocardium. Most of the myocardium is located in the lower two chambers of the heart called ventricles.
Locate the tip of the heart or the apex. Only the left ventricle extends all the way to the apex.
Place the heart in the dissecting pan so that the front or ventral side is towards you (the major blood vessels are on the top and the apex is down). The front of the heart is recognized by a groov e that extends from the right side of the broad end of the heart diagonally to a point above & to your left of the apex.

The heart is now in the pan in the position it would be in a body as you face the body. Locate the following chambers of the heart from this surface:

 Left atrium - upper chamber to your right  Left ventricle - lower chamber to your right  Right atrium - upper chamber to your left  Right ventricle - lower chamber to your left.

While the heart is still in this position in the dissecting pan, locate these blood vessels at the broad end of the heart:  Coronary artery - this blood vessel lies in the groove on the front of the heart & it branches over the front & the back side of the heart to supply fresh blood with oxygen & nutrients to the heart muscle itself.  Pulmonary artery - this blood vessel branches & carries blood to the lungs to receive oxygen & can be found curving out of the right ventricle (lower chamber to your left)  Aorta - major vessel located near the right atria & just behind the pulmonary arteries to the lungs. Locate the curved part of this vessel known as the aortic arch. Branching from the aortic arch is a large artery that supplies blood to the upper body.  Pulmonary veins - these vessels return oxygenated blood from the right & left lungs to the left atrium (upper chamber on your right)  Inferior & Superior Vena Cava - these two blood vessels are located on your left of the heart and connect to the right atrium (upper chamber on your left). Deoxygenated blood enters the body through these vessels into the right receiving chamber. Use your probe to feel down into the right atrium. These vessels do not contain valves to control blood flow.

9. Describe the function of all the external structures of the heart. Record you data in Data Table 1.

Procedure: INTERNAL

Use scissors to cut through the side of the pulmonary artery and continue cutting down into the wall of the right ventricle. Be careful to just cut deep enough to go through the wall of the heart chamber. (Your cutting line should be above & parallel to the groove of the coronary artery.)
With your fingers, push open the heart at the cut to examine the internal structure. If there is dried blood inside the chambers, rinse out the heart.
Locate the right atrium. Notice the thinner muscular wall of this receiving chamber.
Find where the inferior & superior vena cava enter this chamber & notice the lack of valves.
Locate the valve between the right atrium and right ventricle. This is called the tricuspid valve. The valve consists of three leaflets & has long fibers of connective tissue called chordae tendinae that attach it to papillary muscles of the heart. This valve allows blood flow from the right atrium into the right ventricle during diastole (period when the heart is relaxed). When the heart begins to contract ( systole phase), ventricular pressure increases until it is greater than the pressure in the atrium causing the tricuspid to snap closed.
Use your fingers to feel the thickness of the right ventricle and its smooth lining. Also note the network of irregular muscular cords on the inner wall of this chamber.
Find the septum on the right side of the right ventricle. This thick muscular wall separates the right & left pumping ventricles from each other.

Name: ______________________ Date: Period:_

DATA:

Table 1: External Heart

Structure

Make a checkmark in this column if you found the structure

Function

(2 points each)

Left Atrium

Left Ventricle

Right Atrium

Right Ventricle

Coronary Artery

Pulmonary Artery

Aorta

Pulmonary Vein

Superior & Inferior Vena Cava

Table 2: Internal Heart

Structure

Make a checkmark in this column if you found the structure

Function

(2 points each)

Tricuspid Valve

Mitral Valve (bicuspid valve)

Aortic Semilunar Valve

Septum

Data Analysis and Conclusions

1. Why are the walls of the left ventricle thicker than the walls of the right ventricle? (8 points)

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2. Pulmonary circulation carries blood between the heart and the lungs. Systemic circulation carries blood to the rest of the body. In what chambers of the heart does pulmonary circulation begin and end? In what chambers does systemic circulation begin and end? (8 points)

Lab result and lab answer dissection, Study Guides, Projects, Research of Anatomy

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Partial preview of the text

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Heart Dissection

Background:

Objectives:

Materials:

Procedure: EXTERNAL

9. Describe the function of all the external structures of the heart. Record you data in Data Table 1.

Procedure: INTERNAL

Name: ______________________ Date: Period:_

DATA:

Table 1: External Heart

Structure

Function

Table 2: Internal Heart

Structure

Function

Data Analysis and Conclusions

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___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

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Lab result and lab answer dissection, Study Guides, Projects, Research of Anatomy

Related documents

Partial preview of the text

Download Lab result and lab answer dissection and more Study Guides, Projects, Research Anatomy in PDF only on Docsity!

Heart Dissection

Background:

Objectives:

Materials:

Procedure: EXTERNAL

9. Describe the function of all the external structures of the heart. Record you data in Data Table 1.

Procedure: INTERNAL

Name: ______________________________ Date:____________ Period:_____

DATA:

Table 1: External Heart

Structure

Function

Table 2: Internal Heart

Structure

Function

Data Analysis and Conclusions

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Name: ______________________ Date: Period:_