Anatomy of the heart

1. ANATOMY AND PHYSIOLOGY OF
THE HEART
DR. SSEKAWU CHARLES

2. LOCATION OF THE HEART
• In the thoracic cavity
• Medially btn lungs in the mediastinum
• Separated from other structures by pericardium or
pericardial sac and sits in its own space called the
pericardial cavity
• Dorsal surface: lies near the vertebrae
• Interior surface: sits deep to sternum and costal
cartilages
• The base : at the level of 3rd costal cartilage
• Inferior tip (apex): lies just to the left of the sternum
btn the junction of 4th and 5th near the articulation
with costal cartilage

3. LOCATION OF THE HEART conti……
• Greater veins
– Superior venae cavae
– inferior vanea cavae
– Pulmonary veins
• Greater arteries
– Aorta
– Pulmonary trunk
• Attached to the surface of the heart called the Base of the
heart
• Right side: deflected anteriorly
• Left side: deflected posteriorly

5. CHAMBERS AND CIRCULATION THROUGH THE HEART
• Four chambers
– Right atrium and ventricle
– Left atrium and ventricle
• Upper chambers
– Right atrium
– Left atrium
• Act as receiving chambers and contracts
to push blood into the lower chambers
• Lower chambers
– Right ventricle
– Left ventricle
• Serves as primary pumping chambers of
the heart propelling blood to the lungs
or the rest of the body

6. CHAMBERS AND CIRCULATION THROUGH THE HEART
• Two distinct but linked circuits
– Pulmonary circuit : transport
blood from and to lungs
– Systemic circuit : transports
oxygenated blood to tissues
and return deoxygenated blood
• Right Ventricle
– Pumps deoxygenated blood
into pulmonary trunk to the
lungs and bifurcates into left
add right pulmonary arteries
– Pulmonary trunk and arteries
are the only arteries in post
natal body that carry relatively
deoxygenated blood
– Pulmonary veins are the only
veins in the body that carry
highly oxygenated blood
Left Ventricle
- Pumps oxygenated blood into
the aorta and many branches of
the systemic circuit .
- Superior vena cavea and inferior
venae returns blood to right
atrium which pumps blood into
right ventricle

7. Membranes of Heart
• Directly surrounds the heart and defines the pericardial
cavity called pericardium or pericardial sac.
• Also surrounds the root and the major vessels or areas of
closest proximity to the heart
• Consist of 2 distinct sub layers
– Outer fibrous pericardium
• Made up of tough, dense connective tissue
• Protects the heart and maintains its position in the thorax
• Avoid over expansion of the heart
• Inner serous pericardium (more delicate)
– Consist of 2 layers
• Parietal pericardium: fused to the fibrous pericardium
• Inner visceral pericardium (epicardium): fuse to heart and is part of
heart wall
• The pericardial cavity, filled with lubricating serous fluid,
lies btn the epicardium and the pericardium

9. Surface Features of the Heart
• Auricles
– Superficial leaf like extension of the atria near the
superior surface of the heart, one on each side
– Are relative thin walled structures that can fill with blood
and empty into the atria or upper chambers of the heart.
– Sometimes referred to as atrial appendages.
• Sulcus
– Series of fat filled grooves along the surface of the heart
– Where major coronary blood vessels located
– Examples
• Deep coronary sulcus – located btn atria and ventricles
• Anterior interventricular sulcus – visible in the anterior surface
of the heart
• Posterior interventricular sulcus – visible on posterior views of
surface of the heart

11. Layers of the heart
• Composed of three layers of unequal thickness
• From superficial to deep
– Epicardium
– Myocardium
– Endocardium
• Mycordium
– Middle and thickest layer
– Made largely of cardiac muscles cells
– Build upon a frame work of collagenous fibers, blood vessels that supply the
mycordium and nerve fibers that help regulates the heart.
– Its contraction pumps blood through the heart and into the major artery
– The muscle pattern is elegant and complex as, the muscle cell swiri and spiral
around the chambers of the heart
– They form a figure 8 pattern around the atria and around the bases of the
great vessels and around the ventricle
– They are more complex swirling pattern allows the heart to pump blood more
effectively
– Muscle of the left ventricles are much thicker and better developed than that
of the right in order to overcome the high resistance required to pump blood
into the long systemic circuit

12. Layers of the heart conti……
• Endocardium
– Inner layer
– Joined to mycordium with a thin layer of connective
tissue
– Lines the chambers where the blood circulates and covers
the heart values.
– It is made of simple squamus epithelium called
endothelium
– Its continuous with the endothelial lining of the blood
vessels
– Regulate the contraction of the muscle with in the
mycordium.
– Regulates the growth pattern of cardiac muscle cells
throughout life
– Creates env’t in surrounding tissue fluid that regulates
ionic concentrations and state of contractility

14. Internal Structure of The Heart
• Septa of the heart
– Refers to a wall or partition that divides the heart
chambers
– Are physical extension of the myacardium lined with
endocardium
1. Inter- atrial septum
- Btn the atria
- Fossa ovalis – an Oval shaped depression in inter-atrial
septum
- A remnant of Foremen ovale ( opening of fetal heart)
- Foramen ovale- allow blood in the fatal heart to pass directly from
the right atrium to the left atrium, allowing blood to bypass the
pulmonary circuit and closed immediately after birth with septum
primum that previously acted as a valve closes the foramen ovale
to establish the typical cardiac circulation pattern

15. Septa of the heart
2. Inter-ventricular Septum :
- Btn two ventricles
- Thicker than inter-atrial
septum
3. Atrio- ventricular septum
- Btn atria and ventricles
- Marked by presence of four
openings that allows blood to
move from atria into ventricles
and from ventricles into
pulmonary trunk and aorta
- Each opening has valves (
specialized structure to ensure
one way blood flow )
- Valves btn atria and ventricles are
Antrio- Ventricular valves
- Valves at the openings that lead t
the pulmonary trunk and aorta –
Semilnar valves

16. Internal Structure of The Heart
3. Right atrium
– Serves as the receiving chamber for the blood returning to the heart from systemic
circulation
– Includes two major systemic vein
• Superior vanae cavae drain region superior to the diaphragm , the head, Thoracic region, neck
and upper limb
• Inferior vanae cavae drain blood from diaphragm, the lower limb, abdominal pelvic region
– Large coronary vein ( Coronary sinus that drain the heart myocardium )
4. Right ventricle
– Receives blood from right atrium through the tricuspid value
– Its contraction generates pressure that forces blood into pulmonary trunk and
atrium , to prevent backflow , papillary muscle also contracts, generating tension
on the chordae tendineae preventing the flaps of valves from being forced into
atria and regurgitation of the blood into the atria during vetricular contraction
– Trabeculae Corneae : ridges of cardiac muscles surrounded by endocardium that a
lines the walls of ventricles.
– Moderator band : band of cardiac muscle covered by endocardium that reinforce
the thin walls of the right ventricle, it also plays a role in cardiac conduction
– Contraction of right ventricles eject blood into pulmonary trunk which branches
into the left and right pulmonary arteries that carry blood to the lungd
– At the base of the pulmonary trunk is the pulmonary semilunar valve that prevent
back flow from the pulmonary trunk

17. Internal Structure of The Heart
5. Left Atrium
– Receive blood from pulmonary veins
– Contains no pectinate muscle , but has an auricle that
includes these pectinate ridge
– Opening between left atrium and ventricles is guarded by
the mitral valves
6. Left Ventricle
– Thicker than right ventricle
– Has trabeculae corneae but no moderator band
– Mitral valves connected to papillary muscle via chordae
tindineae
– There are two papillary muscles on the left ,i.e anterior
and posterior as opposed to three in the right ventricle
– It is a major pumping chamber for systemic circuit, it eject
blood into the aorta through the aortic semilunar valve

18. Internal Structure of The Heart
7. Heart valve, structure and functions
– Has four vales
– Ensure unidirectional blood flow through the heat

19. Heart valve, structure and functions
1. Right atrio- ventricular value / tricuspid valve
– Btn the right atrium and right ventricles
– Consist of three flaps or leaflets
– Made of endocardium reinforced with additional
connective tissue
– The flaps are connected by chordae tendineae to
the papillary muscle which control the opening
and closing of the valves
– There are 3 papillary muscles supporting the valve
: anterior, posterior and septal which corresponds
to the three sections of the valve

20. Heart valve, structure and functions
2. Pulmonary Semilunar valve/pulmonic valve or
Right semilunar valve
– At the emerging base of the pulmonary trunk from
the right ventricles
– Consist of three small flaps of endothelium reinforced
with connective tissue.
– When ventricles relaxes , the pressure differential
causes blood to flow back into the ventricle from
pulmonary trunk filling the pocket like flaps of the
pulmonary valve causing them to close and produce
an audible sound.
– There no papillary muscles or chordae tendineae

21. Heart valve, structure and functions
3. Mitral / Bicuspid / Left atrio- ventricular valve
– Located at the opening btn left atrium and left ventricle
– Consist of two cusps known as anterior medial cusp and
posterior medial cusp.
– Cusps are attached by chordae tendineae to two papillary
muscle that project from the wall of the ventricles
4. Aortic valve
– At the base of the aorta
– Prevents backflow from the aorta
– Composed of three flaps
– When ventricles relaxes and blood attempts to flow back
into the ventricles from the aorta, blood fill the cusps of
the valve causing it to close and producing an audible
sound.

22. • Two atrio ventricular valves are opened and 2
semilunar valves are closed
– Occurs when both atria and ventricles are relaxed and
when the atria contract to pump blood into the
ventricles .
• Atrio Ventricular valve closed while the two
semilunar valves open:
– Occurs when the ventricles contracts to eject blood into
the pulmonary trunk and aorta
– Closure of the two atrio-ventricular valves prevents
blood from being forced back into the atria

23. • When the ventricles begin to contract , pressure
with in ventricles rises and blood flow to words the
area of lowest pressure, which is initially in the
atria, the blood flow causes the cusps of triscuspid
and mitral value to close/