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The Cardiovascular System (I)The Cardiovascular System (I)The HeartThe Heart
MediastinumMediastinum
MediastinumMediastinum
• The space between the 2 lungs
Sup.: FIRST RIB
Inf.: diaphragm
Ant.: sternum
Post.: VERTEBRAL COLUMN
Heart SurfacesHeart Surfaces
1. Anterior (sternocostal):
2. Inferior (diaphragmatic):
3. Base:
mostly Lf. Atrium
Posterior surface of the heart
4. Apex:
tip of Lt ventricle
Inferior Surface
Posterior Surface
Anterior Surface
Site for posterior surface of the heart (Base)
Site for inferior surface of the heart (Diaphragmatic)
Heart Borders
• Right border:
From inferior
surface to base
• Left Border
Pulmonary border
From apex to base
Surface projection• Determined by 4 points- Superior right point
3rd Rt CC- Superior left point
2nd Lt CC- Inferior left point
5th intercostal space- Inferior right point
6th Rt CC
Covering of the Heart
Coverings of the HeartCoverings of the Heart
• Covering fibroserous sac of 2 layers of tissues that encloses the heart
• Outer: fibrous (fibrous pericardium)
• Inner: serous (serous pericardium)
• Fxn.: 1. Protection 2. Lubrication (friction)
Fibrous PericardiumFibrous Pericardium
• Strong single layer of dense CT
• fuse to great vessels
• Prevent overstretching
• Protection and anchorage
Serous PericardiumSerous Pericardium
• 2 layers of mesothelial cells that are continuous with each other
• Outer (Parietal):
lines fibrous pericardium
reflects around the roots of large vessels
to become continuous with
• Inner (Visceral):
closely attached to the heart
Epicardium (outer heart layer)
Layers of the Heart wall• 3 layers:
1. Epicardium: visceral layer of serous pericardium
2. Myocardium: cardiac muscle
3. Endocardium: thin layer of endothelial cells supported by thin layer of CT
Myocarditis: inflammation of myocardium
Endocarditis: inflammation of endocardium
Fibrous Skeleton of the Heart4 rings of dense CTSurround the valvesFuse with one another
Chambers of the heart4 chambers:-2 atria
-2 ventricles
Rt ½ of Heart:Pulmonary pump
Lt ½ of Heart:Systemic pump
Right AtriumRight Atrium
- Receives deO2 bld. From the body
- Forms Rt. Border of the heart
- Composed of:smooth walled chamber &rough out pouch (auricle)
Rough = pectinate muscle
- Border between:crista terminalis
Outside:sulcus terminalis
- Atrial septum (fetal remnants): Fossa ovalis Anulus ovalis
Openings of Rt. AtriumOpenings of Rt. Atrium1. SVC:
bld. from upper body
2. IVC:
bld. From lower body / larger
4. Coronary Sinus:
Between IVC & A-V orifice
Bld form heart wall
3. A-V orifice:
Ant. to IVC
Guarded by tricuspid valve
Rt. VentricleRt. Ventricle
muscular projections:
1. Papillary muscles:
-Cone-shaped projections
-Attach the cusps of A-V valve via Chordae tendineae
2. Trabeculae carneae:
-prominent muscular ridges
OpeningsOpenings
• A-V orifice:guarded by tricuspid valve
• Pulmonary opening:opens into pulmonary trunk
guarded by pulmonary valve
Lf. AtriumLf. Atrium• Most of the base of Heart
• Inner wall:
Smooth anteriorly and posteriorly
Pectinate muscles are confined to Lt auricle
• 4 openings for P. V.: blood from lungs
• 1 opening for mitral valve
Left VentricleLeft Ventricle
• Thickest part of the Heart
• Forms apex of Heart
• papillary m.
• Chordae tendineae
• Opens into Ascending Aorta
** Ductus arteriosus
Heart ValvesHeart Valves
• 4 valves:
- 2 semilunar:
Aortic & Pulmonary
- 2 A-V:
Tricuspid & Mitral
Semilunar ValvesSemilunar Valves
• Pulmonary: 3 Crescent moon-shaped cusps
Cusp: folding of endocardium with C.T. inside
Sinus: space behind each cusp
• Aortic : similar to pulmonary
2 post. & 1 ant. Cusps
Ensures one way blood flow from ventricles into arteries
Atrioventricular ValvesAtrioventricular Valves1. Tricuspid
-Rt. A-V orifice
-3 cusps:
2. Mitral Valve:
-Left A-V orifice
-2 cusps (bicuspid)
• Cusps are Attached to papillary m. through Chordae tendineae
• Valves ensure one way flow of blood from atria to ventricles
Conducting SystemConducting System
Sino-Atrial node (SA node)
Atrio-Ventricular node (AV node)
Atrio-Ventricular Bundle & branches
(bundle of His)
Purkinje fibers
(subendocardial plexus)
Arterial Supply of the HeartArterial Supply of the Heart
• Coronary arteries:
Right Coronary artery
Left Coronary artery
• From ascending aorta
Right Coronary ArteryRight Coronary ArteryBetween pulmonary trunk & Rt. Auricle
Rt. AV groove
(Posteriorly) anastomose with
Lf. Coronary
Branches:
1. Rt. Marginal artery
2. Post. interventricular
Left Coronary ArteryLeft Coronary Artery
• Larger but shorter
• Arises between pulmonary trunk
& Lt Auricle
• Divides to:
1. ant. interventricular a.
2. circumflex a
Venous DrainageVenous Drainage
• 3 main veins Coronary Sinus
1. Great: Ant2. Middle: Post3. Small: Rt. Margin
-Anterior cardiac veinsOpen directly into Rt atrium
Blood circulation
• Pulmonary Circulation:
Rt ventricle
Lungs
Lt atrium
• Systemic Circulation:
Lt ventricle
Entire Body
Rt atrium