Name ____________________________ Date _________________ Period _____ Score out of 10 _____
Corrected by ___________________________
Sheep Heart Dissection
What are the chambers, valves, and blood vessels of the heart?
What path does blood take through the heart?
The heart is a fist-sized muscle located to the left of the center of the chest. The heart contains four
chambers. The upper chambers are called atria. The lower chambers are called ventricles. Between
each chamber, there are valves that prevent the backflow of blood.
Blood is carried away from the heart by blood vessels called arteries and carried back toward the
heart by blood vessels called veins. Arteries and veins are connected by capillaries. Arteries have
muscular, elastic walls to help move the blood through the body. Veins have one-way valves to prevent
the backflow of blood on its return to the heart.
Oxygen-poor blood from cells of the body enters the heart through the right atrium and is pumped
into the right ventricle. The blood then travels into the pulmonary artery, which goes into the lungs.
In the lungs, the blood gives off carbon dioxide and picks up oxygen. The oxygen-rich blood returns to
the heart by way of the pulmonary vein.
The blood enters the left atrium and is pumped into the left ventricle. The blood is pumped out of the
heart through the aorta to cells in the rest of the body.
The muscular wall of the left ventricle is thicker than the wall of the right ventricle because it has to
pump the blood to the entire body. Blood leaving the right ventricle only goes to go to the lungs.
Each time the ventricles contract, blood is forced through the arteries. This force causes a beat, or
pulse, that is felt in arteries at the wrist, neck, and temple. The pulse is exactly the same as the
heartbeat.
In this investigation you will examine the chambers, valves, and blood vessels of the heart. You will also
trace the path of blood through the heart. Use the above information, your PowerPoint notes, and the
textbook to help you answer the questions in this lab.
Materials
• sheep heart
• dissecting tray
• probe
• metric ruler
• scissors/scalpel
• tweezers
Procedure (Day 1) You will not cut the heart open today!
You do NOT need to write in complete sentences.
Identify the right and left sides of the heart
Obtain a sheep heart and place the heart in a dissecting tray. Imagine the heart in the body of a
person facing you. The left side of their heart is on their left, but since you are facing them, it is on
your right. Position your heart in the tray so that it matches the diagram below.
