N1012 Lab 2 Student Handout (1)

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Memorial University of Newfoundland *

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1002

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Biology

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Feb 20, 2024

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docx

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N1012 Fall 2023 LAB 2: Anatomy of the Heart - Student handout (PLEASE PRINT AND BRING TO LAB) Lab Overview: This lab will focus on the content covered in content from chapters 18 (Heart) of the textbook and is designed to give you an opportunity to do ‘do’ some of the anatomy and physiology we have talked about in this chapter. How to prepare for the lab: Read through the lab before you attend and review any content that you are unsure of. This lab will focus heavily on bones and skeletal anatomy, so a review of the lectures on the axial and appendicular skeleton will be helpful. What to bring: Please print this document and bring it with you to the lab! You will also need your lab coat, your stethoscope , something to write with, your lecture notes, and a willingness to get involved and have some fun! Participating in labs is a great way to help solidify some of the course content – the more engaged you are the better! Lab 1 Objectives:  Describe the location of the heart  Name and describe the covering and lining tissues of the heart  Name and locate the major anatomical areas and structures of the heart when provided with an appropriate model, image, or dissected sheep hear, and describe the function of each.  Explain how the atrioventricular and semilunar valves operate  Distinguish blood vessels carrying oxygen-rich blood from those carrying carbon dioxide – rich blood, and describe the system used to color code them in images.  Explain why the heart is called a double pump, and compare the pulmonary and systemic circuits.  Trace the pathway of blood through the heart.  Trace the functional supply of the heart and name the associated blood vessels.  Describe the histology of cardiac muscle and state the importance of intercalated discs and the spiral arrangement of its cells. ACTIVITY 1: Using the Heart Model to Study the Heart Anatomy  Using the Heart models and posters provided locate the following structures: o Aorta o Pulmonary Arteries o Pulmonary Veins o Auricle of the Atrium o Left/Right Atrium o Left/Right Ventricle o Superior/Inferior Vena Cava

 Put the posters and notes away and identify the same structures without referring to notes or posters.  Describe the location of the heart in the thoracic cavity. ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Activity 2: Sheep Heart Dissection Dissecting a sheep’s heart is a valuable exercise because it is similar in size and structure to the human heart. Materials:  Sheep heart  Dissecting tray  Dissecting instruments  Gloves Observe the External Structures of the Heart: 1. In N 1002 we mimicked and discussed the linings of the body’s cavities. Remember the balloon activity? The Pericardial sac has been removed from your specimen the heart sits in a cavity of the body and sits in a covering called the pericardial sac. What function does this Pericardial sac provide? ______________________________________________________________________________

______________________________________________________________________________ ______________________________________________________________________________ 2. Examine the external surfaces of the heart. Notice the accumulation of adipose tissue, Carefully scrape away some of the fat with the scalpel to expose the coronary vessels. How do the coronary vessels different in function to the great vessels of the heart? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 3. Identify the Base and the Apex of the heart, and then identify the two wrinkled auricles, earlike flaps of tissue projecting from the atria. What are the function of these structures? ______________________________________________________________________________ ______________________________________________________________________________ 4. The remainder of the heart muscles is ventricular tissue. To identify the left ventricle compress the ventricles on each side. The Right side feels much thinner and somewhat flabby when compressed. The Left side feels thicker and more solid, why? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 5. Identify the pulmonary trunk and the Aorta extending from the superior aspect of the heart. The pulmonary trunk is more anterior, and you may see its division into the right and left pulmonary arteries if it has not been cut too closely to the heart. What is the difference in the walls of the aorta as compared to the pulmonary trunk? Which one has more stretch? Why? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 6. Cut through the wall of the Aorta until you see the aortic valve. Is this a semilunar or atrioventricular (AV) valve? _____________________________________________________ What are differences between the Semilunar valves and the AV Valves? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 7. Turn the heart to view its posterior surface. Try to identify the four thin-walled pulmonary veins entering the left atrium. Identify the superior and inferior vena cava . Compare the diameter of the vena cava with the diameter of the aorta. Which is larger? __________________________________ Which has thicker walls? ____________________________

Why do you suppose these differences exist? ______________________________________________________________________________ ______________________________________________________________________________ 8. Insert your probe tool into the superior vena cava, through the right atrium, and out the inferior vena cava. Use scissors to cut along the probe so that you can view the interior of the right atrium. Observe the tricuspid valve. How many cusps does it have? ________________________ 9. Return to the pulmonary trunk and cut through its anterior wall. You can see the pulmonary valve. How does its action differ from that of the tricuspid valve? ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ 10. Position the heart on its lateral side and cut the heart into anterior and posterior sections opening it like a book. Observe:  Four chambers of the heart.  Semilunar valves  Atrioventricular valves  Chordae tendineae  Papillary muscles  Intraventricular septum Using the rulers provided measure the thickness of the right and left ventricular walls in meters and record the numbers ____________________. Compare the shape of the left ventricular cavity to the shape of the right ventricular cavity. Are the papillary muscles and chordae tendineae observed in the right ventricle also present in the left ventricle? __________________ Count the number of cusps in the mitral valve. How does this compare with the number seen in the tricuspid valve? ____________________________________________________________ Which valves are anchored by the chordae tendineae? __________________________________ Which valves close when the cusps fill with blood? ____________________________________ With your lab mates, visualize and discuss the pathway of blood through the heart trying to recall the names of and identify each section of the heart as the blood would travel through. Dispose of organic heart tissue in the designated container, rinse the dissecting tray and metal instruments and dispose of green handled sharp scalpel in Big yellow sharps disposal container. Using an antibacterial wipe clean your lab table before proceeding with the remainder of your lab. Activity 3: The Cardiac Cycle

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