Location & structure of the heart

1. By : V.Atputhavadivel
Reg. No : 09
Diploma in Teaching and Supervision -2006
Post Basic College of Nursing Colombo

2. General objective
By completion of this session the student
should be able to acquire knowledge in
position and structure of the heart
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3. 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
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4. 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.

6. ….
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

7. 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.

10. 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.

11. Pericardium
A double-layered membrane
Surrounds the heart like a sac.
The outer layer of the pericardium surrounds
the roots of the heart's 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,

12. 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.

13. 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.

14. Interior of the heart

15. 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.

16. 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.

17. The Left half of the Heart.
The half is responsible for the circulation
of oxygenated
blood to all parts of the body
The Left Atrium.
The left atrium is thin-walled like the
right atrium and it situated in the broad
end of the heart.
The Left Ventricle.
The left ventricle is characterized by its
exceptionally thick muscular wall.

18. The Valves of the Heart.

19. 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.

20. 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.

21. Thank you