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9. (a) (i) Cardiac muscle may be described as a **contractile** tissue - Leaving Cert Biology - Question 9 - 2004
Question 9
9. (a) (i) Cardiac muscle may be described as a **contractile** tissue. Explain the meaning of the underlined term. (ii) Which chamber of the heart has the greates... show full transcript
Worked Solution & Example Answer:9. (a) (i) Cardiac muscle may be described as a **contractile** tissue - Leaving Cert Biology - Question 9 - 2004
Step 1
Explain the meaning of the underlined term.
Answer
Cardiac muscle can be described as a contractile tissue because it has the ability to shorten or contract. This unique property allows the heart to pump blood effectively throughout the body, facilitating circulation. The contraction of cardiac muscle cells enables them to generate the force needed to propel blood during each heartbeat.
Step 2
Which chamber of the heart has the greatest amount of muscle in its wall?
Answer
The left ventricle has the greatest amount of muscle in its wall. This is because it must generate a substantial amount of force to pump oxygenated blood to the entire body, unlike the other chambers which pump blood only to nearby structures.
Step 3
Describe how you dissected a mammalian heart in order to investigate the internal structure of atria and ventricles.
Answer
To dissect a mammalian heart, first, identify the anterior and posterior sides. Begin by placing the heart on a cutting board with the ventral side facing up. Use scissors to make an incision along the atria and ventricle walls to observe the internal structure. Be sure to maintain safety procedures by wearing gloves and goggles throughout the dissection.
Step 4
Draw a labelled diagram of your dissection to show the location and structure of the bicuspid and tricuspid valves.
Answer
A clear diagram should be drawn to depict the four chambers of the heart, indicating the bicuspid valve located between the left atrium and left ventricle, as well as the tricuspid valve situated between the right atrium and right ventricle. Ensure both valves are clearly labelled for identification.
Step 5
State the procedure that you followed to expose a semilunar valve.
Answer
To expose a semilunar valve, first cut the aorta or the pulmonary artery. This incision allows for easy access to the base of the heart where these valves are located. Be cautious to follow anatomical landmarks during this procedure.
Step 6
Step 7