anatomy and embryology of heart by dr pankaj bhosale

1. ANATOMY AND
EMBRYOLOGY OF THE
HEART
- DR PANKAJ BHOSALE
MBBS , DA, DNB , FIACTA
(Fellow in cardiothoracic anaesthesia)

3. 3
Heart in pericardial cavity
Figure 18.1

4. Gross Anatomy
• A conical hollow muscular organ approximately the
size of your fist
• Location :
Middle mediastinum behind sternum,
costal cartilages of 3,4,5 ribs
Superior surface of diaphragm
Left of the midline
Anterior to the vertebral column,
• Directed forward and to left .
• Anterior most is the apex.
• Average measurement: 12cm X9cm
• Weight: 325±75 g in men 275± 75 g in women

5. Pericardium
• Pericardial cavity is lined by the pericardium.
• Pericardium – a double-walled sac around the
heart composed of:
1. A superficial fibrous pericardium
2. A deep two-layer serous pericardium
a. The parietal layer lines the internal surface of the
fibrous pericardium
b. The visceral layer or epicardium lines the surface of the
heart
They are separated by the fluid-filled pericardial cavity.
Pericardial fluid acts as a lubricant reducing friction.

7. The Function of the
Pericardium:
Protects and anchors the
heart
Prevents overfilling of the
heart with blood
Allows for the heart to work
in a relatively friction-free
environment
The clear tissue being Lifted up by the
scalpel Is the pericardium

8. Applied anatomy- Pericarditis
• Various pathogens may infect the
pericardium.
• The inflamed pericardial surfaces rub
against one another.
• Makes a distinct scratching sound.
• Cardiac tamponade could occur due to the
increased pericardial fluid in the
pericardial cavity. This condition restricts
the movement of the heart.

9. External features
• Sulci:
1.Coronary (atrioventricular) sulci-
a) anterior
b) posterior
1.Interatrial groove visible posteriorly
2.Interventricular sulci/ groove
3.Crux is the posterior basal surface at junction
of coronary and posterior interventricular
sulci and internally atrial septum joins the
ventricular septum

10. Surfaces
• Diaphragmatic or inferior
• Anterior of sternocostal
• Left surface
Borders
• Right- SVC and RA
• Left- LV and La
• Inferior- RV and laterally LV

11. The anterior and posterior interventricular sulci are shallower
depressions that mark the boundary line between the left
and right ventricles.
These areas usually contain a large amount of fat. The sulci
contain the arteries and veins that feed the heart.
The heart has an attached base and a free apex.
The inferior tip is called the apex.
In a typical adult the heart measures approximately 12.5 cm
from the base to the tip.
The apex reaches to the fifth intercostal space, 7.5 cm to the
left of the midline.

12. 12
• Vessels returning blood to the heart include:
1. Superior and inferior venae cavae
2. Right and left pulmonary veins
• Vessels conveying blood away from the heart
include:
1. Pulmonary trunk, which splits into right and left
pulmonary arteries
2. Ascending aorta (three branches) –
a. Brachiocephalic
b. Left common carotid
c. Subclavian arteries
External Heart: Major Vessels of
the Heart (Anterior View)

13. • Arteries – right and left coronary (in
atrioventricular groove), marginal,
circumflex, and anterior interventricular
arteries
• Veins – small cardiac, anterior cardiac,
and great cardiac veins
External Heart: Vessels that
Supply/Drain the Heart (Anterior View)

14. Chapter 18, Cardiovascular System 14
External Heart: Anterior View
Figure 18.4b

15. • Vessels returning blood to the heart
include:
1. Right and left pulmonary veins
2. Superior and inferior venae cavae
• Vessels conveying blood away from the
heart include:
1. Aorta
2. Right and left pulmonary arteries
External Heart: Major Vessels of
the Heart (Posterior View)

16. Chapter 18, Cardiovascular System 16
External Heart: Posterior View

17. OVERVIEW OF THE CARDIOVASCULAR
SYSTEM
• Pulmonary circuit
• Systemic circuit
• Arteries (Including the coronary arteries)
• Veins (Including the coronary veins)
• Capillaries (Arterioles & Venules)
• Four chambers of the heart

18. 18
Pathway of Blood Through the Heart
and Lungs
• Right atrium  tricuspid valve  right ventricle
• Right ventricle  pulmonary semilunar valve 
pulmonary arteries  lungs
• Lungs  pulmonary veins  left atrium
• Left atrium  bicuspid valve  left ventricle
• Left ventricle  aortic semilunar valve  aorta
• Aorta  systemic circulation

19. Heart Wall
• Epicardium – visceral layer of the serous
pericardium
• Myocardium – cardiac muscle layer
forming the bulk of the heart
• Fibrous skeleton of the heart –
crisscrossing, interlacing layer of
connective tissue
• Endocardium – endothelial layer of the
inner myocardial surface

20. Walls of the
Heart

21. Myocardial Thickness and Function
Thickness of myocardium varies according to the function of the
chamber
Atria are thin walled, deliver blood to adjacent ventricles
Ventricle walls are much thicker and stronger
– right ventricle supplies blood to the lungs (little flow
resistance)
– left ventricle wall is the thickest to supply systemic circulation

22. Thickness of Cardiac Walls
Myocardium of left ventricle is much thicker than the right.

23. DIFFERENCE FROM OTHER MUSCLE FIBRES

25. ORIENTATION OF FIBRES

27. Chambers
of the heart
• Right atrium RA
• Right ventricle RV
• Left Atrium LA
• Left Ventricle LV
• When not filled with blood, the outer portion of
each atrium deflates and becomes a lumpy,
wrinkled flap.
• This extension is called the auricle (looks like
an external ear).

28. Cardiac Chambers
• a) Right atrium Wide based blunt
appendage, crista terminalis separates
trabeculated from non-trabeculated
portion.
• b) Left atrium Long, narrow appendage,
smooth walls.
• c) Right ventricle Coarsely trabeculated
inlet/sinus, outlet portion.
• d) Left ventricle Fine trabeculations
inlet/sinus and outlet portions.

29. Chapter 18, Cardiovascular System 29
Gross Anatomy of chambers: Frontal Section
Figure 18.4e

30. • Atria - receiving chambers of the heartAtria - receiving chambers of the heart
– Receive venous blood returning to heartReceive venous blood returning to heart
– Separated by an interatrial septum (wall)Separated by an interatrial septum (wall)
• Foramen ovale - opening in interatrial septum in fetusForamen ovale - opening in interatrial septum in fetus
• Fossa ovalis - remnant of foramen ovaleFossa ovalis - remnant of foramen ovale
• Each atrium has a protruding auricleEach atrium has a protruding auricle
• Pectinate muscles mark atrial wallsPectinate muscles mark atrial walls
• Pump blood into ventriclesPump blood into ventricles
• Blood enters right atria from superior and inferiorBlood enters right atria from superior and inferior
venae cavae and coronary sinusvenae cavae and coronary sinus
• Blood enters left atria from pulmonary veinsBlood enters left atria from pulmonary veins
ATRIA OF THE HEARTATRIA OF THE HEART

31. Right Atrium
• SVC
- IVC
- Crista terminalis
- Coronary sinus
- Tricuspid valve
- Fossa ovalis
- Triangle of Koch
- Tendon of Todaro
- Inferior isthmus

32. Lecture on Anatomy of the Heart ( drnnamanisamuel@gmail.com)
Left auricleLeft auricle －－ projecting to theprojecting to the
right, pectinate muscles in wallright, pectinate muscles in wall
Four inletsFour inlets －－ fourfour orifices oforifices of
pulmonary veinspulmonary veins open through theopen through the
posterior wallposterior wall
One outletOne outlet －－ leftleft
atrioventricular orificeatrioventricular orifice, blood, blood
leaves through left atrioventricularleaves through left atrioventricular
orifice to left ventricleorifice to left ventricle

33. Left atrium

34. Ventricles are the discharging chambers of the heartVentricles are the discharging chambers of the heart
Papillary muscles and trabeculae carneae muscles markPapillary muscles and trabeculae carneae muscles mark
ventricular wallsventricular walls
Separated by an interventricular septumSeparated by an interventricular septum
Contains components of theContains components of the conduction systemconduction system
Right ventricle pumps blood into the pulmonary trunkRight ventricle pumps blood into the pulmonary trunk
Left ventricle pumps blood into the aortaLeft ventricle pumps blood into the aorta
Thicker myocardium due to greater work loadThicker myocardium due to greater work load
Pulmonary circulation supplied by right ventricle is a much lowPulmonary circulation supplied by right ventricle is a much low
pressure system requiring less energy output by ventriclepressure system requiring less energy output by ventricle
Systemic circulation supplied by left ventricle is a higher pressureSystemic circulation supplied by left ventricle is a higher pressure
system and thus requires more forceful contractionssystem and thus requires more forceful contractions
))
VENTRICLE OF THE HEARTVENTRICLE OF THE HEART

36. Ventricular Differences
• The anatomical differences between the
right and left ventricles are as follows:
• The right ventricle is relaetively thin. The
left ventricle has a massive muscular wall.

37. • both the RV and the LV have been described as having three
components: the inlet, apical trabecular, and outlet portions
• The posterior (paraseptal) wall of the infundibulum is formed by a
prominent muscular ridge, known as the supraventricular crest
(crista supraventricularis or ventriculoinfundibular fold), which
separates the inlet and outlet components of the RV
• Septomarginal trabeculation:The septomarginal trabeculation is a
prominent Y-shaped muscular strap reinforcing the septal surface. It
bifurcates into anterosuperior and inferoposterior limbs
• Posterior limb: gives rise to medial papillary muscle
• Body: anterior papillary muscle and MODERATOR BAND

38. View from the right side of the heart.

39. 1 2
3
Chordae tendineae
Papillary muscle

40. Interatrial septumInteratrial septum
• Located between right and left atriaLocated between right and left atria
• Contains fossa ovalisContains fossa ovalis
Interventricular septumInterventricular septum Located between right and leftLocated between right and left
ventriclesventricles
• upper membranous partupper membranous part
• thick lower muscular partthick lower muscular part
Fibrous skeletonFibrous skeleton
• Fibrous rings that surround the atrioventricular,Fibrous rings that surround the atrioventricular,
pulmonary, and aortic orificespulmonary, and aortic orifices
• Left and right fibrous trigonsLeft and right fibrous trigons
Lecture on Anatomy of the Heart
( drnnamanisamuel@gmail.com)
SEPTUMS/FIBROUS SKELETONSEPTUMS/FIBROUS SKELETON

41. INTERATRIAL SEPTUM
.

42. Interventricular
septum

43. Left
Ventricle
Heart
Wall
Right Ventricle Heart Wall

44. Fibrous Skeleton Of The HeartFibrous Skeleton Of The Heart

45. 45
Heart Valves
• Heart valves ensure unidirectional blood flow
through the heart
• Atrioventricular (AV) valves lie between
the atria and the ventricles
– AV valves prevent backflow into the atria when
ventricles contract
• Chordae tendineae anchor AV valves to
papillary muscles

46. Atrioventricular Valves
• Prevent backflow of blood from the
ventricles back into the atria.
• Chordae tendineae and papillary muscles
play an important role in this process.
• Ventricular diastole the ventricles relax
and the ventricles refill.
• The chordae tendineae are loose and
offer no resistance to the flow of blood.

47. 47
Heart Valves

48. Heart Valves

49. During ventricular systole the ventricles begin to contract
blood moving back towards the atria swings the cusps
together closing the valves.
The chordae tendineae and papillary muscles stops the
cusps from swinging into the atria.
If those two structures are cut or damaged the valves act
as swinging doors, and there is backflow, or
regurgitation.
Mitral valve damage can especially occur in women
after pregnancy.
Chordae tendinae and papillary muscles

50. Mitral valve -Anatomy

53. Mitral Valve Prolapse

54. Tricuspid Valve

56. Tricuspid valveTricuspid valve
• Guards right atrioventricular orificeGuards right atrioventricular orifice
• Three triangular cusps: anterior, posterior andThree triangular cusps: anterior, posterior and
septal, the base of cusps are attached to fibrousseptal, the base of cusps are attached to fibrous
ring surrounding the atrioventricular orificering surrounding the atrioventricular orifice
• Chordae tendineaeChordae tendineae －－ fine, white, connectivefine, white, connective
tissue cords, attach margin of cusps totissue cords, attach margin of cusps to papillarypapillary
musclesmuscles
Mitral valveMitral valve
Guards left atrioventricular orificeGuards left atrioventricular orifice
• Two triangular cuspsTwo triangular cusps －－ anterior and posterioranterior and posterior
with Similar structures to those of rightwith Similar structures to those of right
Lecture on Anatomy of the Heart
( drnnamanisamuel@gmail.com)

57. 57
Semilunar Heart Valves
• Semilunar valves prevent backflow of
blood into the ventricles
• Aortic semilunar valve lies between the
left ventricle and the aorta
• Pulmonary semilunar valve lies between
the right ventricle and pulmonary trunk

58. Chapter 18, Cardiovascular System 58
Semilunar Valve Function
Figure 18.10

59. Chapter 18, Cardiovascular System 59
Atrioventricular Valve Function
Figure 18.9

60. Aortic valve – Anatomy

61. The AORTIC ROOT has four anatomic components:
• The aortic sinuses or sinuses of Valsalva
• The aortic annulus or aortoventricular junction
• The leaflets
• The sinotubular junction
SINGLE
FUNCTIONAL
UNIT
Aortic Root - Anatomy

62. Sinotubular
Junctinon
MyocardiumFibrous tissue
Anterior leaflet of the mitral valve
Membranous septum
Normal: 55% 45%
Marfan/Bicuspid aortic valve: 65% 35%
N L R
Histology:
The aortic root is in fibrous continuity with
the anterior leaflet of the mitral valve and
the membranous septum; connective
tissue (fibrous strands) unites the aortic
root to the interventricular septum.
Aortic Annulus (aortoventricular junction

63. Sinuses of ValsalvaSinuses of Valsalva
The segment of the arterial wall
of the aortic root delineated by a
leaflet proximally and by the
sinotubular junction distally is
called the aortic sinus or sinus
of Valsalva.
They are 3 elliptical inlets that
have a very important role in the
dynamics of circulation :
• Guaranteeing coronary artery
perfusion during systole;
•Creating eddies to close the
aortic leaflets during diastole

64. It represents the terminal edge of the aortic root and it
is constituted by the imaginary line that connects
together the 3 commissures.
Young
adults
AA>STJ
Adults
AA =
STJ
Elderly
AA<STJBASE = Aortic Annulus (AA)
Sinotubular
Junction

65. CONDUCTION SYSTEM

66. Conduction System
• Sinoatrial node - anterolateral RA
• Interatrial conduction pathways - not well defined and
somewhat controversial
• Inferior isthmus (right atrium) anterior Bachman's bundle (left
atrium), middle Wenkebachs, posterior Thorel
• Atrioventricular node - triangle of Koch
• Bundle of His - AV node to membranous septum, usually
located on the inferior/posterior wall of the membranous
septum
• Left bundle branch - left ventricular septal surface into multiple
branches
• Right bundle branch - below medial papillary muscle via
septal and moderator bands to anterior papillary muscle

68. Sinuatrial nodeSinuatrial node (SA node)(SA node)
• Called the pacemaker cell (P cell)Called the pacemaker cell (P cell)
• Located at the junction of right atrium andLocated at the junction of right atrium and
superior vena cava, upper part of the sulcussuperior vena cava, upper part of the sulcus
terminalis, under the epicardiumterminalis, under the epicardium
Lecture on Anatomy of the Heart
( drnnamanisamuel@gmail.com)

69. Atrioventricular nodeAtrioventricular node (AV node)(AV node)
• Located in the lower part of interatrial septum justLocated in the lower part of interatrial septum just
above the orifice of coronary sinus, under theabove the orifice of coronary sinus, under the
endocardiumendocardium
• Lower part related to membranous part ofLower part related to membranous part of
interventricular septuminterventricular septum
Atrioventricular bundleAtrioventricular bundle (AV bundle)(AV bundle)
• Passes forward through right fibrous trigon to reachPasses forward through right fibrous trigon to reach
inferior border of membranous partinferior border of membranous part
• Divides into right and left branches at upper borderDivides into right and left branches at upper border
of muscular part of interventricular septumof muscular part of interventricular septum
Lecture on Anatomy of the Heart
( drnnamanisamuel@gmail.com)

70. Heart Blood Supply
• Coronary circulation demands high
oxygen and nutrients for the cardiac
muscle cells.
• Coronary arteries originate at the base of
the ascending aorta.
• Interconnections between arteries called
anastomoses ensure a constant blood
supply.

72. • Coronary artery dominance[edit]
• The artery that supplies the posterior third of interventricular septum
(PDA)[2]
determines the coronary dominance.[3]
• If the posterior descending artery is supplied by the
right coronary artery (RCA), then the coronary circulation can be
classified as "right-dominant".
• If the posterior descending artery is supplied by the circumflex
artery (CX), a branch of the left artery, then the coronary circulation
can be classified as "left-dominant".
• If the posterior descending artery is supplied by both the right
coronary artery and the circumflex artery, then the coronary
circulation can be classified as "co-dominant".

73. Chapter 18, Cardiovascular System 73
Coronary Circulation: Venous
Supply
Figure 18.7b

74. • VENOUS DRAINAGE 2 systems:
• 1) Superficial system: which drains LV. It
is formed of coronary sinus and anterior
cardiac veins that open into the RA.
• 2) Deep system: which drains the rest of
the heart. It is formed of thebasian veins
and arterio-sinusoidal vessels that open
directly into the heart chamber

77. Great, Posterior, small,
Anterior, Middle Cardiac
Veins carry blood from
The coronary capillaries
To the coronary sinus.
Left coronary artery supplies
The left ventricle. Circulflex
Curves left meeting with
The right coronary artery.
Left anterior decending
Supplies the posterior
Decending artery
(interventricular).

78. 78
Microscopic Anatomy of Heart
Muscle
• Cardiac muscle is striated, short, fat,
branched, and interconnected
• The connective tissue endomysium acts as
both tendon and insertion
• Intercalated discs anchor cardiac cells
together and allow free passage of ions
• Heart muscle behaves as a functional
syncytium
InterActive Physiology®
:
Cardiovascular System: Anatomy Review: The Heart

79. Chapter 18, Cardiovascular System 79
Microscopic Anatomy of Heart
Muscle
Figure 18.11

80. • Striation[edit]
• Cardiac muscle has cross striations formed by rotating segments
of thick and thin protein filaments. Like skeletal muscle, the primary
structural proteins of cardiac muscle are myosin and actin.
• The actin filaments are thin, causing the lighter appearance of the I
bands in striated muscle, whereas the myosin filament is thicker,
lending a darker appearance to the alternating A bands as observed
with electron microscopy.
• However, in contrast to skeletal muscle, cardiac muscle cells are
typically branch-like instead of linear.

81. • T-tubules[edit]
• Another histological difference between cardiac muscle and skeletal
muscle is that the T-tubules in the cardiac muscle are bigger and wider
and track laterally to the Z-discs.
• There are fewer T-tubules in comparison with skeletal muscle.
The diad is a structure in the cardiac myocyte located at
the sarcomere Z-line.
• It is composed of a single T-tubule paired with a terminal cisterna of
the sarcoplasmic reticulum. The diad plays an important role
in excitation-contraction coupling by juxtaposing an inlet for the action
potential near a source of Ca2+
ions.
• This way, the wave of depolarization can be coupled to calcium-
mediated cardiac muscle contraction via the sliding filament mechanism.
Cardiac muscle forms these instead of the triads formed between
the sarcoplasmic reticulum in skeletal muscle and T-tubules. T-tubules
play critical role in excitation-contraction coupling

82. • The cardiac syncytium is a network of cardiomyocytes connected to each
other by intercalated discs that enable the rapid transmission of electrical
impulses through the network, enabling the syncytium to act in a
coordinated contraction of the myocardium
• Intercalated discs are complex adhering structures that connect the single
cardiomyocytes to an electrochemical syncytium (in contrast to the skeletal
muscle, which becomes a multicellular syncytium during mammalian
embryonic development). The discs are responsible mainly for force
transmission during muscle contraction. Intercalated discs consist of three
different types of cell-cell junctions: the actin filament anchoring adherens
junctions, the intermediate filament anchoring desmosomes, and gap
junctions. They allow action potentials to spread between cardiac cells by
permitting the passage of ions between cells, producing depolarization of
the heart muscle.

83. Extrinsic Innervation of the Heart
• Heart is
stimulated by the
sympathetic
cardioaccelerator
y center
• Heart is inhibited
by the
parasympathetic
cardioinhibitory
center

84. Embryology of the heart

85. Cardiovascular System is derived
from Mesoderm

86. Vascular system appears in the
middle of third week

87. Steps in the embryology of the
vascular system
• ESTABLISHMENT OF THE HEART FIELD
• FORMATION AND POSITION OF THE HEART TUBE
• FORMATION OF THE CARDIAC LOOP
• MOLECULAR REGULATION OF CARDIAC DEVELOPMENT
• DEVELOPMENT OF THE SINUS VENOSUS
• FORMATION OF THE CARDIAC SEPTAE
• FORMATION OF THE CONDUCTING SYSTEM OF THE HEART
• VASCULAR DEVELOPMENT

88. PRIMARY HEART FIELD
Progenitor heart cells lie in the epiblast, immediately adjacent to the cranial end of the
primitive streak. From there, they migrate through the streak and into the splanchnic layer o f
lateral plate mesoderm where some form a horseshoe-shaped cluster of cells called the
primary heart field (PHF) cranial to the neural fold

89. FORMATION AND POSITION
OF THE HEART TUBE

90. 2 processes responsible for
positioning of the heart
1. Folding of the embryo in a
cephalocaudal direction
2. Simultanous folding laterally

91. Initially, the central portion of the
cardiogenic area is anterior to
the oropharyngeal membrane
and the neural plate. With
closure of the neural tube and
formation of the brain vesicles,
however, the central nervous
system grows cranially so rapidly
that it extends over the central
cardiogenic region and the future
pericardial cavity. As a result of
growth of the brain and cephalic
folding of the embryo, the
oropharyngeal membrane is
pulled forward, while the heart
and pericardial cavity move first
to the cervical region and finally
to the thorax.

92. Figures showing effects of the rapid growth of the brain on positioning
of the heart. Initially the cardiogenic area and the pericardial cavity are
in front of the oropharyngeal membrane. A. 18 days. B. 20 days. C. 21
days. D. 22 days

93. Lateral folding apposes paired heart tube primordia
and brings dorsal aorta to midline
Heart primordia fuse to form tubular heart

94. Rest of the steps follow this video:link below
https://www.youtube.com/watch?v=RpZHiwkFUM4

95. Thank you