By : V.AtputhavadivelReg. No : 09Diploma in Teaching and Supervision -2006Post Basic College of Nursing Colombo
General objective By completion of this session the student should be able to acquire knowledge in position and structure of the heart gpujhdNehf;fk; ,g;ghlg;gFjpapd; Kbtpy; khztHfs; ,jaj;jpd; miktplk; kw;Wk; ,jaj;jpd; fl;likg;G vd;gdgw;wpa G+uz mwpit ngw;wpUj;jy; Ntz;Lk;
Specific objectives To write down the shape, size and weight of the heart. To identify the anatomicaiposition of the heart. To describe the structure of the heart gpuj;jpNafkhd Nehf;fq;fs;,g;ghlg;gFjpia khztHfs; fw;wgpd;G gpd;tUk; jfikfisngw;wpUj;jy; Ntz;Lk;• ,jaj;jpd; tbtk; gUkd; kw;Wk; epiw vd;gtw;iwFwpg;gpLjy;.• ,jaj;jpd; clypay;hPjpahd miktplj;ij milahsk; fhZjy;.• ,jaj;jpd; cs; ntsp mikg;ig tpghpj;jy;
The heart is a roughly cone –shaped hollow muscular organ. An adult human heart above 10 cm long, weighs between 200 and 350 grams and is slightly larger than a fist. Each day, the average heart beats 100,000 times, pumping about 7,600 liters (2,000 gallons) of blood.
…. Thoracic cavity, between the lungs, behind and slightly to the left of the sternum A base above, it is extends to the level of the 3nd rib. The apex below, it is about 9cm left away from midline, at the 5 th intercostals space
Inferiorly – The apex rests on the central tendon of the diaphragm Superiorly_ The great blood vessels ie; the aorta ,superior vena cava, pulmonary artery and pulmonary veins. Posteriorly- The esophagus, trachea, left and right bronchus, descending aorta , inferior vena cava and thoracic vertibrae . Laterally-The lungs the left lung overlaps the left side of the heart. Anteriorly-The sternum, ribs and intercostals muscles.
Three layers of tissue form the heart wall. The outer layer of the heart wall is the pericardium, The middle layer is the myocardium, The inner layer is the endocardium.
Pericardium A double-layered membrane Surrounds the heart like a sac. The outer layer of the pericardium surrounds the roots of the hearts major blood vessels and is attached by ligaments The inner layer of the pericardium is attached to the heart muscle. A coating of fluid separates the two layers of membrane,
Myocardium Specialized cardiac muscle found only in the heart. It is not under voluntary control but like skeletel muscle. Nuleus, intercalated disc, branching cell. The myocardium is thickest at the apex and thins out towards the base.
Endocardium. This forms the lining of the myocardium and the heart valve. It is a thin , smooth glistening membrane. It consist of flattened epithelial cell.
Interior of the heart…. A muscular septum divides the heart internally into a left and a right half. Each half is subdivided into two chambers, the atrium (reception) and the ventricle (pump chamber) . Internally all four chambers have a smooth membranous lining, the endocardium.
The Right half of the Heart. The right half of the heart is responsible for the circulation of deoxygenated (oxygen-poor) blood to the lungs so that it may be oxygenated. This circulation is called pulmonary circulation or lesser circulation.The Right Atrium.The right atrium is thin walled and is situated at the broad end of the heart.The Right Ventricle. The right ventricle receives the deoxygenated blood from the right atrium.
The Left half of the Heart.The half is responsible for the circulationof oxygenatedblood to all parts of the bodyThe Left Atrium.The left atrium is thin-walled like theright atrium and it situated in the broadend of the heart.The Left Ventricle.The left ventricle is characterized by itsexceptionally thick muscular wall.
We have learned from this section Shape, dimension, weight of the heart Location of the heart, Organ associated with the heart, Tissue composition and layers, Interior structure of the heart.
Assignment Describe the heart wall composed three layers of tissue.References : Anne Waugh, Allison Grant, Ross and Wilson Anatomy and Physiology in Health and Illness, (2001), Churchill Livingstone, Edinburgh London.