Download Practical class 3 THE HEART and more Exercises Cardiology in PDF only on Docsity!
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Practical class 3
THE HEARTHE HEARTHE HEARTHE HEARTHE HEARTTTTT
OBJECTIVESBy the time you have completed this assignment and any necessary further reading or study you
should be able to:-1. Describe the fibrous pericardium and serous pericardium, identify them on a suitable prosection, and explain their function.2. Describe the major gross features of an intact heart.
- Demonstrate the major features of the interior of the right atrium.4. Name and describe the main features of, and the differences between, the right and left ventricular interiors.5. Identify the heart valves in appropriate prosections and outline their functions.
- Describe the conducting system of the heart.7. Summarise the nerve supply to the heart and describe briefly the neurological basis of referred pain from the heart.8. Describe the origin, course and distribution of the coronary arteries and summarise the venous drainage of the heart.9. List the main areas of myocardium affected by occlusion of the major coronary arteries.
Background readingBackground readingBackground readingBackground readingBackground reading Rogers: Chapter 7; Cardiovascular System 37; The Heart and Pericardium
ANTERIOR
POSTERIOR
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Which chambers of the heart form part of:the pulmonary circulation? the systemic circulation? Examine the roots of the great vessels and identify the aortic and pulmonary valves. How would you describe these valves?
When do they close? What are the aortic sinuses?
BLOOD SUPPLY TO THE HEART
Arterial supply The arterial supply to the heart is provided by the rightrightrightrightright and left coronary arteriesleft coronary arteriesleft coronary arteriesleft coronary arteriesleft coronary arteries.
Where do the coronary arteries arise? Identify the right and left coronary arteries and study the distribution of their branches on aprosected heart and on the resin cast of the coronary circulation. Which coronary artery usually gives the greater supply to the specialised conducting tissue of theheart?
Draw and label the branches of the coronary arteries listed, on the following diagram (indicatethose arteries running on the posterior surface of the heart by broken lines): left and right coronary arteriesleft and right coronary arteriesleft and right coronary arteriesleft and right coronary arteriesleft and right coronary arteriescircumflex arterycircumflex arterycircumflex arterycircumflex arterycircumflex artery anterior and posterior interventricular arteriesanterior and posterior interventricular arteriesanterior and posterior interventricular arteriesanterior and posterior interventricular arteriesanterior and posterior interventricular arteriesleft and right marginal arteriesleft and right marginal arteriesleft and right marginal arteriesleft and right marginal arteriesleft and right marginal arteries
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the anterior interventricular artery What is: coronary thrombosis? myocardial infarction? angina pectoris?
VENOUS DRAINAGE OF THE HEARTAll the major arterial branches of the coronary circulation are accompanied by veins. Most
eventually drain into the largeposterior surface of the heart and opens into the coronary sinuscoronary sinuscoronary sinuscoronary sinuscoronary sinus , which lies in the right atriumright atriumright atriumright atriumright atrium. atrioventricular grooveatrioventricular grooveatrioventricular grooveatrioventricular grooveatrioventricular groove on the Look for: great, middle, small and anterior cardiac veinsgreat, middle, small and anterior cardiac veinsgreat, middle, small and anterior cardiac veinsgreat, middle, small and anterior cardiac veinsgreat, middle, small and anterior cardiac veins
Draw and label these vesels which drain the heart on the following diagram, again indicate those marginal veinmarginal veinmarginal veinmarginal veinmarginal vein on the posterior surface by dotted lines.
ANTERIOR
NERVE SUPPLY OF THE HEARTNerve fibres reach the heart from the cardiac autonomic plexuscardiac autonomic plexuscardiac autonomic plexuscardiac autonomic plexuscardiac autonomic plexus , which lies beneath the arch of
the aorta. Where do the fibres to the cardiac plexus arise?
Fibres are distributed from themyocardium and the coronary arteries. cardiac plexuscardiac plexuscardiac plexuscardiac plexuscardiac plexus to the sinu-atrialsinu-atrialsinu-atrialsinu-atrialsinu-atrial and atrio-ventricular nodesatrio-ventricular nodesatrio-ventricular nodesatrio-ventricular nodesatrio-ventricular nodes , the How is the action of the heart affected by: sympathetic stimulation? parasympathetic stimulation? Pain from the heart e.g in angina pectoris, is commonly experienced over the left side of the chestand medial aspect of the left arm. Classical angina (literally choking) is like a belt tightening around the chest and radiating to the left arm. It is often triggered by an increase in the heart ratewith critical coronary artery stenosis usually about 75% occlusion. How is the pattern of “cardiac referred pain” accounted for?
INTERIOR OF THE HEARTStudy a prosected heart which has flaps cut in the walls of its chambers.
Use the following table to indicate the flow of blood through the heart. Re ceivesbloodfro m Pumpsbloodto Rightatrium RLeigfhttavtreiunmtricle Leftventricle
What is the auricle of the atrium? The What was the function of this foramen? (^) fossa ovalisfossa ovalisfossa ovalisfossa ovalisfossa ovalis marks the position of the foetal foramen ovale.
When in life does it close? If you examine all the prosected hearts which are available you may find a specimen in which asmall opening persists in the upper part of the fossa ovalis. Do you think that such a defect is functionally significant? Why? Now examine the right ventricle. Identify the following structures: tricuspid valvetricuspid valvetricuspid valvetricuspid valvetricuspid valvechordae tendinaechordae tendinaechordae tendinaechordae tendinaechordae tendinae papillary musclespapillary musclespapillary musclespapillary musclespapillary musclestrabeculae carnaetrabeculae carnaetrabeculae carnaetrabeculae carnaetrabeculae carnae
Label these structures on the previous diagram where possible. moderator bandmoderator bandmoderator bandmoderator bandmoderator band What is the function of the moderator band?
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Read an account of the conducting system of the heart, then write a summary of this informationin the space below.
Ventricular contraction begins at the apex and progresses towards the outflow vessels. What is the functional advantage of this arrangement?
What is the function of the chordae tendinae? Congenital malformation or disease may lead to incomplete closure (opening ( stenosisstenosisstenosisstenosisstenosis ) of the heart valves. incompetenceincompetenceincompetenceincompetenceincompetence ) or incomplete What would be the effect on the right atrium of tricuspid valve incompetence? How might this defect manifest itself clinically? How is regurgitation of blood from the atria to the venous system prevented? Compare the left and right ventricles. Describe and comment on any differences in: the thickness of their walls
the atrioventricular valves. In which direction would blood tend to flow through a ventricular septal defect?
