Download heart - Yengage

Pericardium

Conical fibro serous sac

Situated in the middle
mediastinum

Encloses the heart and
roots of great vessels

Composed of two layers
 Fibrous layer
 Serous layer
Fibrous pericardium
 Conical sac made up of fibrous tissue
 Apex - tunica adventitia of great vessels
and continuous with pre-tracheal layer
 Base- central tendon of diaphragm
Both of them developed from the septum
transversum
 Anteriorly- attached to the posterior
surface of the sternum by superior and
inferior sterno - pericardial ligaments
 Behind related to the posterior mediastinum
 On each side related to mediastinal pleura
Serous pericardium
 Closed sac lies within fibrous pericardium
 Consist of visceral and parietal layers
 Parietal layer lines the fibrous pericardium
 Visceral layer (epicardium) covers the heart and
roots of great vessels
 Pericardial cavity contains serous fluid
 Lined by mesothelium
Sinuses of pericardium
 The continuity between parietal and visceral layers is
established in the form of two tubes
 Arterial tube
 Venous tube
Transverse sinus
 Transverse passage between
the arterial and venous ends of
heart tubes
 Developed from the
degeneration of central cells
of dorsal mesocardium
Boundaries
• Anteriorly
• Posteriorly
• Inferiorly
• On each side
Oblique sinus
Blood supply
Arterial supply:
 Fibrous and parietal layers – branches of
internal thoracic and descending
thoracic aorta
 Visceral layer – coronary arteries
Venous drainage:
 Fibrous and parietal layers – internal
thoracic and azygos veins
 Visceral layer – coronary sinus
Nerve supply
 Fibrous and parietal layer – phrenic
nerves
 Visceral layer – vagus and sympathetic
nerves
Applied anatomy
Surgical significance of transverse sinus:
Ligature may be passed through the
sinus around the aorta and pulmonary
trunk to control hemorrhage during
cardiac surgery
Surgical significance of transverse sinus:
Ligature may be passed
through the sinus around
the aorta and pulmonary
trunk to control
hemorrhage during cardiac
surgery
Pericarditis
 Inflammation of serous pericardium
 Causes chest pain
 Serous pericardium may become rough
Pericardial friction rub may be heard
with stethoscope over the left sternal border
Pericardial effusion
 Excess pericardial fluid compress the heart and
decreases the diastolic capacity
 Reduces cardiac output
Pericardial tamponade
Pericardiocentesis:
 Drainage of fluid from the pericardial cavity to
relieve cardiac tamponade
HEART
HEART
Muscular
Located
Placed
organ
in the middle mediastinum
obliquely behind body of
sternum,costal cartilages
HEART
Weighs
approx 300 g in males,
250 g in females

Has four chambers

Two atria

Two ventricles
EXTERNAL FEATURES

Atrioventricular groove (coronary
sulcus)

Interatrial groove

Interventricular groove

Auricles – extensions of each
atria
EXTERNAL FEATURES
APEX
 Formed by the left ventricle
 Located in the left 5th
intercostal space
 Just medial to the midclavicular
line
EXTERNAL FEATURES
BASE

Forms the posterior surface

Formed by the left atrium and a
small part of the right atrium

Openings of four pulmonary veins

Openings of superior and inferior
vena cavae
SURFACES AND BORDERS

Surfaces:


Anterior (Sternocostal)

Inferior (diaphragmatic)

Right

Left
Borders:

Superior

Inferior

Right

Left

Upper border- by two atria
Right
border- by the right
atrium

Inferior border- by the
right ventricle and left
ventricle

Left border- by the left
ventricle and partly by the
left auricle
BORDERS
STERNOCOSTAL SURFACE
Formed
mainly by the right
atrium and right ventricle

Partly by the left ventricle
and left auricle
Superficial
cardiac dullness
SURFACES
DIAPHRAGMATIC SURFACE

Rests on the central
tendon of the diaphragm

Formed by the right &
left ventricles
Posterior
groove
interventricular
SURFACES
SURFACES
LEFT SURFACE
Formed
by left ventricle
& left auricle

Coronary sulcus
RIGHT ATRIUM

Receives venous blood from
the whole body
 Pumps it to the right
ventricle through the tricuspid
orifice
RIGHT ATRIUM
Elongated vertically
Upper end is prolonged and forms
right auricle
 Shallow vertical groove – sulcus
terminalis
Corresponds to the internal
muscular ridge – crista terminalis
 Contains the sino-atrial node –
pacemaker of the heart
 Right atrioventricular groove
RIGHT ATRIUM
Right atrioventricular
orifice
 Called tricuspid
 Guarded by a valve with
three leaves/cusps
 Maintains the
unidirectional flow of blood
RIGHT ATRIUM

Inlets:
 Superior vena cava
 Inferior vena cava
 Coronary sinus
 Anterior cardiac veins
 Venae cordis minimi
RIGHT ATRIUM – INTERNAL FEATURES
 Divided into three parts
 Smooth posterior wall –
sinus venarum
 Rough anterior wall –
pectinate part
 Septal wall
 Most of the tibutaries open
into it
SVC – upper end
 IVC – lower end –
guarded by a rudimentary
valve
 Coronary sinus – between
the IVC and Rgt. AV
orifice – guarded by the
Thebesian valve
 Intervenous tubercle of Lower
SINUS VENARUM
 Transverse muscular ridges
– musculi pectinati
 Extends from crista
terminalis to RAVO
 Forms a comb-like
appearance
 Extends into the right
auricle to form a reticular
network
PECTINATE PART
Shallow oval depression – fossa
ovalis
Formed by septum primum
 Prominent upper border of the
fossa – limbus fossa ovalis
 Formed by the lower border
of septum secundum
 Remains of foramen ovale
SEPTAL PART
RIGHT
VENTRICLE
 Receives blood from the
right atrium
 Pumps it through the
pulmonary trunk to the lungs
 Forms the inferior border,
sternocostal surface, small part
of the diaphragmatic surface
RIGHT VENTRICLE-INTERNAL FEATURES
 Inflowing part – muscular ridges
- trabeculae carneae
 Outflow part (infundibulum) is
smooth-leads to pulmonary trunk
 Ridge separating the two parts
– supraventricular crest
 Two orifices:
 Right atrioventricular
 Pulmonary
RIGHT VENTRICLE
Trabeculae carneae- three
types
 Ridges (fixed)
 Bridges
 Papillary muscles
Anterior – largest
 Posterior/Inferior –
small and irregular
 Septal – small nipples
RIGHT VENTRICLE
Chordae tendinae – Strings
that connect the tips of the
papillary muscles to the cusps
Each papillary muscle is
attached to two contiguous
cusps
 Septomarginal trabecula
(moderator band)
 Wall is thinner than that of
the left ventricle
LEFT ATRIUM
 Forms the left 2/3 of the
base of the heart
 Receives oxygenated blood
from the lungs through four
pulmonary veins
 Pumps the blood into the
left ventricle through the left
atrioventricular orifice
LEFT ATRIUM INTERNAL FEATURES
 Anterior wall is formed by
the interatrial septum
 Posterior wall receives the
four pulmonary veins
Musculi pectinati are present
only in the left auricle
 Fossa lunata – formed by
septum secundum
LEFT VENTRICLE
Receives oxygenated blood
from the left atrium
 Pumps it out through the
aorta
Inflow part- trabeculae
carneae
 Smooth part – vestibule –
leads to the aorta

LEFT VENTRICLE
Two orifices
 Left atrioventricular
(mitral)
 Aortic
 Two papillary muscles
 Anterior
 Posterior
 Walls are three times thicker
than right ventricle
 Two parts – lower
muscular, upper membranous
Bulges into the cavity of
the right ventricle
INTERVENTRICULAR
SEPTUM
VALVES OF THE HEART
 Maintain unidirectional
flow of blood
 Prevents regurgitation
 Two pairs of valves
 Atrioventricular
 Semilunar
ATRIOVENTRICULAR VALVES
TRICUSPID
VALVE
 Three cusps – anterior, posterior and septal
BICUSPID
VALVE
 Two cusps – anterior and posterior
SEMILUNAR
VALVES
 Shape of the cusps
 Each has 3 cusps, attached to
the walls of the vessel
SEMILUNAR
VALVES
 Each cusp forms a small pocket
 Free margin contains a central nodule
 From each side of the nodule, a thin smooth
margin – lunule
HISTOLOGICAL STRUCTURE OF THE HEART
Three layers
 Endocardium – endothelium and subendothelial
connective tissue
 Myocardium – Thickest layer of the wall
 Epicardium – visceral layer of serous pericardium
NERVE SUPPLY TO THE HEART
 Cardiac plexus – can be divided into superficial
and deep
 SYMPATHETIC
 Preganglionic passing through T2-T5 ganglia
 Postganglionic passing through the cervical and
upper thoracic ganglia
 Cardio-acceleratory
NERVE SUPPLY TO THE HEART
 PARASYMPATHETIC
 Vagus
 Cardio inhibitory
NERVE SUPPLY TO THE HEART
 Superficial cardiac plexus
 Below the arch of aorta, in front of right
pulmonary artery
 Superior cervical cardiac branch of left
sympathetic chain
 Inferior cervical cardiac branch of left vagus
NERVE SUPPLY TO THE HEART
 Deep cardiac plexus
 Behind the arch of aorta, in front of
bifurcation of trachea
 Cardiac branches derived from cervical and
thoracic ganglia of sympathetic chain
 Cardiac branches from vagus and recurrent
laryngeal nerves
CONDUCTING SYSTEM OF THE HEART
ARTERIAL SUPPLY TO THE HEART
 Two arteries – right and left
coronary arteries
 Inner (100 µm) endothelial
surface by blood in the
chambers
 Anatomically- not end-arteris
 Functionally- end-arteries
RIGHT CORONARY ARTERY
 Arises from the right anterior
aortic sinus
 Emerge on surface of heart b/w
pulmonary trunk and right auricle
 Runs in right anterior coronary
sulcus
 Winds around inferior border to
reach posterior coronary sulcus
 Terminates by anastomosing with
leftcoronary artery
Course
Branches
 Marginal branch
 Posterior interventricular
branch
 Nodal branch- 60% cases
 Right atrial
 Infundibular
 Terminal
Distribution
 Right atrium
 Greater part of right ventricle
 Small part of left ventricle
 Posterior part of interventricular
septum
 Whole conducting system of the
heart except left branch of AV
bundle
LEFT CORONARY ARTERY
 Arises from the left posterior
coronary sinus
 Passes between the left
auricle and pulmonary trunk
 Gives anterior interventricular
artery
 Continues as circumflex
artery in posterior coronary
sulcus
Course
Branches
 Anterior interventricular
branch
 Large diagonal branch
 Left atrial
 Pulmonary
 Terminal
Distribution
 Left atrium
 Greater part of left ventricle
 Small part of right ventricle
 Anterior part of interventricular
septum
 Left branch of AV bundle
Cardiac dominance
 90% cases posses right
coronary predominance
 10% posses left coronary
predominance
VENOUS DRAINAGE OF THE HEART
 Venous blood from the
heart drained by
 Coronary sinus
 Anterior cardiac veins
 Venae cordis minimi
 Largest vein
Present in the left
posterior coronary sulcus
Drains into posterior wall
of the right atrium
 Guarded by a thebesian
valve
CORONARY SINUS
Tributaries:

Great cardiac vein - accompanies
anterior interventricular artery
 Middle cardiac vein- accompanies
posterior interventricular artery
 Small cardiac vein- accompanies
the right coronary artery
 Oblique vein of the left atrium
Posterior vein of left ventricle
Right marginal vein
CORONARY SINUS
ANTERIOR CARDIAC VEINS
 Begin over the anterior
surface of the right
ventricle
 3-4 in number
 Usually open in the right
atrium
VENAE CORDIS MINIMI
 Smallest cardiac veins
 Open directly into all the
chambers
 Numerous on the right side
LYMPHATIC DRAINAGE
 Accompany the coronary arteries and form two
trunks
 Right trunk- brachiocephalic nodes
 Left trunk- tracheobronchial nodes
Applied anatomy
Coronary heart disease
 Sudden and complete occlusion (block) of
branches of coronary arteries lead to
necrosis of the cardiac muscle-myocardial
infarction
 Caused by thrombosis and chronic
atherosclerotic narrowing of lumen
Frequency of occlusion
 Anterior interventricular artery- 40-50%
 Right coronary artery- 30-40%
 Circumflex artery- 15-20%
Angina pectoris
 Incomplete
occlusion of branches
of coronary arteries- Cardiac
pain
 Pain fibres conveyed by
sympathetis cardiac nerves-
T1-T5 spinal segments
Precordium
Tachycardia
Bradycardia
Arrhythmia
Myocarditis, endocarditis, pericarditis
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