Transcript Left ventricle

Angiology
Composition
• Cardiovascular system
• Lymphatic system
The Cardiovascular System
Ⅰ.Introduce
Ⅰ) The organization
— heart central pump
— arteries carry blood away from the heart
— capillaries
— veins transport blood from the capillaries
Blood circulation
• Systemic circulation
• left ventricle→aorta and its
branches→capillaries of
body→superior and inferior
vena cava→right atrium
• Systemic circulation
• Here, the substance exchange between the blood and
tissue cells through capillary wall takes place. The
exchange includes oxygen, carbon dioxide, nutrients,
water and inorganic ions, vitamins, hormones,
metabolic products, antibodies, and defensive cells of
various kinds. Then the arterial blood(rich in oxygen
and nutrients) becomes venous blood(rich in carbon
dioxide and metabolic products ) ,go through superior
vena cava, inferior vena cava, coronary sinus, and the
tributaries of them toward the right atrium.
• Consequentially, this blood enters to the right ventricle.
2.The pulmonary (lesser)
circulation right ventricle
pulmonary trunk
right and left pulmonary
Arteries
pulmonary
capillaries(in lungs)
pulmonary veins
left atrium
• blood gives off carbon dioxide and
acquires oxygen. Thus, the venous blood
becomes arterial blood, go through the
pulmonary veins to the left atrium.
•
Heart
Position
and
relation
External morphology
Cardiac chambers
Conduction
Vessels
Pericardium
Position
• Lies within the
pericardium in middle
mediastinum
• Behind the body of
sternum and coastal
cartilages 2 to 6
• In front of thoracic
vertebrae 5 to 8
• A third of it lies to the
right of median plan and
2/3 to the left
Surface markings of heart
• Right border－corresponds to
a line running from the upper
border of right third costal
cartilage ±1.2cm from the
margin of sternum, downwards
to sixth sternocostal joint
• Apex－in the fifth left
intercostal space 7~9cm from
the midline
• Left border－represented by a
line running from apex
upwards and medially to a
point on lower border of left
second costal cartilage
±1.2cm from sternal margin
• Lower border－represented
by a line joint the lower end of
right border to apex
External
morphology
one apex,
one base,
two surfaces
three borders
three grooves
the apex
formed by the left ventricle
the base
faces backward,upward and to
the right. Formed mainly by the left
atrium and partly by the right atrium.
two surfaces: sternocostal and
diaphragmatic surfaces
three borders: right,left and inferior
borders
*the cardiac apecial incisure is on the
inferior border and right to the apex
*atrioventricular crux is a point of
the coronary and posterior
interventricular grooves. It is a
important superficial mark
three grooves: coronary groove
ant. interventricular groove
post. interventricular groove
•Interatrial sulcus －separates the two atria and is hidden by
pulmonary trunk and aorta in front
External characteristics－a
hollow muscular organ,
pyramidal in shape , somewhat
larger than a closed fist; consists
of four chambers (right and left
atria, right and left ventricles)
• Cardiac apex is formed by left
ventricle and is directed
downwards and forwards to the
left. It lies at the level of the fifth
left intercostal space, 1~2cm
medial to the left midclavicular
line (9cm from the midline)
• Cardiac base is formed by the
left atrium and to a small extent
by the right atrium. It faces
backward, upward and to the
right
Two surface
• Sternocostal surface
is
formed mainly by the right
atrium and right ventricle,
and a lesser portion of its
left is formed by the left
auricle and ventricle. It is
directed forwards and
upwards
• Diaphragmatic surface is
formed the ventricles－
chiefly the left ventricle,
directed backwards and
downwards, and rest upon
the central tendon of the
diaphragm
Three borders
• Right border－vertical,
is formed entirely by right
atrium
• Left border－round, is
mainly formed by the left
ventricle and partly by the
left auricle
• Inferior border－
horizontal, is formed by
the right ventricle and
cardiac apex
Three grooves
• Coronary sulcus (circular sulcus)
which marks the division between
atria and ventricles, contains the
trunks of the coronary vessels and
completely encircles the heart
• Interventricular grooves －
anterior and posterior, mark the
division between ventricles
(which separates the RV from the
LV), the two grooves extend from
the base of the ventricular potion
to a notch called: the cardiac
apical incisure
Atrioventricular crux －a junction
of the posterior interventricular
groove and coronary sulcus
Chambers
• right atrium
• right ventricle
• left atrium
• left ventricle
Chambers of the heart
Right atrium (RA)
Three inlets
•
•
•
Orifice of superior vena cava returns blood
to the heart from the upper half of the body
Orifice of inferior vena cava －returns blood to
the heart from the lower half of the body
Orifice of coronary sinus －returns blood to
the heart from the cardiac muscle
One outlet
－right atrioventricular orifice
• Crista terminalis
－
vertical ridge that from superior
vena cave to inferior vena cave
• Sulcus terminalis －groove on
exterior of heart that corresponds to
crista terminalis
Two parts－separated externally by
sulcus terminalis and internally by
the crista terminalis
• Atrium proper
– In front of the ridge
– Pectinate muscles in wall
– Right auricle －a small conical
muscular pouch, projects to the
left from the root of superior
vena cava, pectinate muscles in
wall
• Orifice of coronary sinus
Lies posterior to the ridge
– Smooth walls
– Fossa ovalis －an oval
depression, a remnant of
the fetal foramen ovale, on
the lower part of interatrial
septum, the most common
location of atrial septal
defects (ASD)
– Limbus fossae ovalis–
prominent margin of fossa
ovalis
Right ventricle (RV)
Receives deoxygenated blood
from right atrium through right
atrioventricular orifice
• One inlet－right
artrioventricular orifice
• One outlet－orifice of pulmonary
trunk
• Two parts－divided by the
supraventricular crest, a
muscular ridge between right
atrioventricular orifice and orifice
of pulmonary trunk
Inflow tract－rough walls
• Trabeculae carneae －
irregularly arranged bundles of
myocardium
• Septomarginal trabecula
－extends from
interventricular septum to base
of anterior papillary muscle,
contains right bundle branch
• Papillary muscles－conicalshaped , anterior, posterior and
septal
Out flow tract
• Conus arteriosus cone-shaped,
smooth area leading upward to
orifice of pulmonary trunk
• Pumps blood through
pulmonary orifice to
pulmonary trunk
Left atrium (LA)
• Left auricle－projecting to the
right, pectinate muscles in wall
• Four inlets－four orifices of
pulmonary veins open through
the posterior wall
• One outlet－left
atrioventricular orifice, blood
leaves through left
atrioventricular orifice to left
ventricle
Left ventricle (LV)
• Has wall three times thicker
than that of right ventricle
• One inlet－left
atrioventricular orifice
• One outlet－aortic orifice
• Two parts－divided by anterior
cusps of mitral valve
– Inflow tract－rough walls
– Outflow tract – aortic vestibule,
smooth area leading to aortic
orifice
Tricuspid valve
•
•
•
Valves
Guards right atrioventricular
orifice
Three triangular cusps: anterior,
posterior and septal, the base of
cusps are attached to fibrous ring
surrounding the atrioventricular
orifice
Chordae tendineae －fine, white,
connective tissue cords, attach
margin of cusps to papillary
muscles
Mitral valve
•
•
•
Guards left atrioventricular
orifice
Two triangular cusps－anterior
and posterior with commissural
cusps between them
(posteromedial and
anterolateral commissures)
Similar structures to those of
right
Similar functions for right and left atriventricular valves
• Open during diastole to allow blood to enter ventricles from
atria
• Closed during systole to prevent regurgitation of blood into
atria
Valve of pulmonary trunk
•
•
Guards the orifice of
pulmonary trunk
Has three semilunar cusps –
each with free border that
has central nodules of
semilunar valve
Aorti vavle
•
•
Guards the aortic orifice
Three semilunar cusps (right,
left and post)
• Three aortic sinuses – bulges
in aortic wall at level of valve
that correspond to cusps
– Right－contains opening
of right coronary artery
– Left－contains opening of
left coronary artery
– Posterior－no opening
Similar functions for
pulmonary and aortic
valves
• Opening during systole,
with cusps pressed toward
wall of vessel as blood is
forced upward
• Closed during diastole
–
–
Ventricular pressure drops
in diastole
Floating together of valve
cusps, with free borders
meeting, thus closing the
valve
Structure of the heart
Walls of heart
• Endocardium－inner coat
of the heart wall, and
continuous with the valve
flaps
• Myocardium
– Arranged spirally
– Attached to fibrous rings
surrounding the four
orifices of heart
• Epicardium －serous
membrane (visceral
pericardium)
Interatrial septum
• Located between right and
left atria
• Contains fossa ovalis and
limbus
Interventricular septum
• Located between right and
left ventricles
• Has upper membranous part
• Has thick lower muscular
part
Fibrous skeleton
• Fibrous rings that surround the
atrioventricular, pulmonary, and
aortic orifices
• Left and right fibrous trigons
• right fibrous trigon sits among the annuli
of the bicuspid valve, the tricuspid valve
and the aotric valve. Inferiorly it adheres
to the muscular part of the
interventricular septum, and forward
connects with the membranous part of
the interventricular septum. Because of
its position located to the center of the
heart, it is also called the central fibrous
body.
• Left fibrous trigon sits between the
annulus of bicuspid valve and the
annulus of the aortic valve. This trigone
is smaller than the right one.
Conduction System
It is consists of the special cardiac
muscles
None of these structures are
macroscopic, but their locations can
be noted.
5 parts:
sinoatrial node
Internodal tracts
atrioventricular node,
atrio-ventricular bundle
Left and right branches
Purkinje fibers.
• Cardiac muscle has an intrinsic rhythmicity that
allows the heartbeat to originate in and be
conducted through the heart without extrinsic
stimulation. Specialized strands of interconnecting
cardiac muscle tissue that coordinate cardiac
contraction constitute the conduction system.
• The conduction system enables the cardiac cycle,
which refers to the events surrounding the filling
and emptying of the chambers of the heart. The
conduction system consists of specialized tissues
that generate and distribute electrical impulses
through the heart.
Conduction system of heart
• Consists of specialized
myocardial cells
Sinuatrial node (SA node)
• Called the pacemaker cell
(P cell)
• Located at the junction of
right atrium and superior
vena cava, upper part of
the sulcus terminalis,
under the epicardium
The SA node initiates the cardiac cycle by producing an electrical
impulse that spreads over both atria, causing them to contract
simultaneously and force blood into the ventricles. The basic
depolarization rate of the SA node is 70 to 80 times per minute.
• The impulse then through internodal tracts, located in the
inferior portion of the interatrial septum just above the
orifice of the coronary sinus passes to the
atrioventricular node. From here, the impulse continues
through the atrioventricular bundle, located at the top of
the interventricular septum. The atrioventricular bundle
divides into right and left bundle branches, which are
continuous with the conduction myofibers within the
ventricular walls —Purkinje fibers. Stimulation of these
fibers causes the ventricles to contract simultaneously.
Atrioventricular node (AV node)
• Located in the lower part of interatrial
septum just above the orifice of
coronary sinus, under the endocardium
• Lower part related to membranous part
of interventricular septum
Atrioventricular bundle (AV bundle)
• Passes forward through right fibrous
trigon to reach inferior border of
membranous part
• Divides into right and left bundle
branches at upper border of muscular
part of interventricular septum
Right and left bundle branches
Right bundle branch－passes down
on right side of interventricular
septum to reach the septomarginal
trabecular and into the base of
anterior papillary muscle. Here it
becomes continuous with the fibers
of Purkinje fibres
• Left bundle branch－passes down
on left side of interventricular
septum beneath the endocardium. It
usually divides into two branches,
which eventually become
continuous with the Purkinje fibers
Purkinje fibers －continuous with
myocardium
• The wall of the heart has its own supply of
systemic blood vessels to meet its vital needs. The
myocardium is supplied with blood by the right
and left coronary arteries. These two vessels
arise from the ascending part of the aorta, at the
location of the aortic (semilunar) valve. The
coronary arteries encircle the heart within the
atrioventricular sulcus, the depression between the
atria and ventricles. Two branches arise from both
the right and left coronary arteries to serve the
atrial and ventricular walls.
Arterial supply
Left coronary artery Arises from
left aortic sinus
• Runs between pulmonary trunk and left
auricle into coronary sulcus
• Branches
– Anterior interventricular branch travels
downward in anterior interventricular groove
around inferior margin of heart to posterior
interventricular groove
– Circumflex branch －travels to left in
coronary sulcus to posterior aspect
• Distribution－supplies left atrium and
ventricle, lesser portion of anterior wall of
right ventricle, and anterior 2/3 of
interventricular septum
Right coronary artery
• Arises from the right aortic sinus
• Runs forward between right auricle
and pulmonary trunk into coronary
sulcus
• Branches
–
–
•
Right marginal branch －travels
along inferior border
Posteror interventricular branch
travels downward in posterior
interventricular groove, it
anastomosises near the apex with the
anterior interventricular branch of the
left coronary artery
Distribution: supplies right atrium and
ventricle, posterior 1/3 of
interventricular septum, posterior wall
of left ventricle, the sinuatrial node
and atrioventricular node
A heart attack often involves a
clot in the coronary arteries or their
branches.
In this illustration, a
clot is shown in the
location of #1. Area
#2 shows the portion
of the damaged heart
that is affected by
the clot.
Image by J. Heuser courtesy of Wikipedia.
Venous drainage
Coronary sinus
• Located in right atrium, runs
transversely in the groove
between the left atrium and
ventricle on the posterior
surface of the heart.
• Carries most of venous blood
from myocardium to right
atrium
• Tributaries
– Great cardiac vein
– Middle cardiac vein
– Small cardiac vein
•
•
Anterior cardiac veins
－3~4 small vessels,
drain into right atrium
Smallest cardiac veins
－drain into all chambers,
mainly atria
Pericardium
1. It comprises 2 sacs:
—the fibrous pericardium
—the serous pericardium:
*parietal layer
*visceral layer
• The parietal pericardium is a loose
fitting serous sac of dense fibrous
connective tissue that encloses and
protects the heart. It separates the heart
from the other thoracic organs and forms
the wall of the pericardial cavity , which
contains a watery, lubricating pericardial
fluid. The parietal pericardium is actually
composed of an outer fibrous pericardium
and an inner serous pericardium.
• The visceral pericardium is serous
pericardium
• It is the serous pericardium that produces
the lubricating pericardial fluid that allows
the heart to beat in a kind of frictionless
bath.
•
.
• The potential space between the
parietal and visceral layers is called
the pericardial cavity. Normally, the
cavity contains a small amount of
serous fluid which acts as a lubricant
to facilitate movements of the heart.
The sinuses of pericardium
Transverse sinus of pericardium －posterior to ascending aorta
and pulmonary trunk, anterior to superior vena cava and left
atrium.
•
The Ascending aorta and the pulmonary trunk can be
clamped by the sinus to block the blood stream temporarily
in operation of the heart.
• Oblique sinus of pericardium－cul-de-sac , posterior to heart,
bounded by pulmonary veins on either side,, lies behind the left
atrium