Download Cardiovascular sysytem

Anatomy
First Prof Pharm. D
Cardio vascular system
Heart
Arsalan
Lecturer
Department Of Pharmacy
University of Peshawar
CARDIOVASCULAR SYSTEM
o
The cardiovascular system consists of heart and the blood vessels.
o
Heart act as a muscular pump that forces the blood into tissues for
nutrients and gases exchange.
o
The blood vessels transports blood between heart and all body
tissues. Blood vessels are arteries and veins. Arteries carries blood
away from heart while veins bring it back.
o
The cardiovascular system has two major divisions

a pulmonary circuit, which carries blood to the lungs for gas exchange and then
returns it to the heart.

a systemic circuit, which supplies blood to every organ of the body.
o
The right side of the heart serves the pulmonary circuit while the left
side of the heart serves the systemic circuit.
THE HEART
o Heart is a four-chambered muscular pump.
o It is a hollow, cone-shaped, muscular organ about the size of a
fist.
o Its average weight is 255 grams in adult females and 310 grams
in adult males.
o The heart beats about 75 times per minute (108,000 times per
day, 42 million times per year).
o It pumps about 700000 gallons of blood per year.
o The heart consists of four chambers, the two atria and the two
ventricles.
LOCATION AND POSITION OF
THE HEART
o The heart is located in the thoracic cavity posterior to the
sternum in between the lungs in the middle mediastinum.
o About two third of the heart is placed left to the midline.
o It is placed slightly oblique such that its right border (right
atrium and ventricle) is present more anteriorly while its left
border (left atrium and ventricle) is present more posteriorly.
o Because the heart is conical to pyramid shaped it has a base and an apex.
o
The posterior (posteriosuperior) surface of the heart, formed primarily by the left
atrium, is called the base.
o The apex of the heart is formed by the inferioanterior surface of the heart i.e. left
ventricle.
o The base is directed toward the right shoulder, and the apex points to the left hip.
o The base is beneath the second rib, and the apex is at the level of the fifth
intercostal space.
o The heart does not rest on the base instead it rest on the diaphragm where it has
its apex.
EXACT SURFACE POSITION OF HEART
o The 2nd left costal cartilage 0.5in (12mm) from the edge of
the sternum;
o The 3rd right costal cartilage 0.5in (12mm) from the sternal
edge;
o The 6th right costal cartilage 0.5in (12mm) from the sternum;
o The 5th left intercostal space 3.5in (9cm) from the midline
(corresponding to the apex beat).
ANATOMY OF THE HEART
• The heart is a muscular pump consisting of four chambers,
two auricles, four valves and a muscular wall all enclosed
within a fluid filled sac, the pericardium.
PERICARDIUM
• The pericardium is a conical fibro-serous sac, in which the heart and the roots of
the great vessels are contained.
• The function of the pericardium is

to keeps the heart in place and limit its motion.

prevent it from over expanding and over filling.

reduces its friction between with its surrounding structures.
• Structurally pericardium is made up of two layers/sacs. The outer layers is called
fibrous pericardium and the inner one is called serous pericardium.
• The fibrous pericardium is tough, dense connective tissue making a
bag like structure, the neck of which is attached base of great vessels
and base is attached to the muscular fibers of the diaphragm.
•
It is also attached to the posterior surface of the sternum by the
superior and inferior sternopericardiac ligaments; the upper passing
to the manubrium, and the lower to the xiphoid process. All these
connections anchors the pericardium in thoracic cavity.
• The serous pericardium is a thin structure and it is
divided into two layers
itself
 The outer one coats the fibrous pericardium and is called parietal layer.
 The inner one coats the heart and is called visceral layer. The visceral
layer is applied closely to the heart that is why it is also called
epicardium.
 In between these two layers is a thin space called pericardial cavity. The
pericardial cavity is filled with small amount of fluid (upto 50ml) called
pericardial fluid. This fluid facilitate smooth frictionless pumping of
the heart
NERVE SUPPLY OF THE PERICARDIUM
• The fibrous pericardium, parietal layer of the serous pericardium are
supplied by the phrenic nerves.
•
Visceral layer of the serous pericardium is innervated by branches of the
sympathetic trunks and the vagus nerves.
HEART WALL
• The hear wall is composed of three layers, the epicardium, the myocardium and the
endocardium.
• The myocardium is the actual functioning muscular part of the heart wall where as
the epicardium is exterior covering and endocardium is its interior covering.
•
•
•
•
ENDOCARDIUM
The endocardium is a thin, smooth membrane which lines the inner surface of the
heart.
It consists of connective tissue and elastic fibers, and is attached to the muscular
structure of the heart by loose elastic tissue which contains blood vessels and
nerves.
The endocardium also covers the heart valves.
It is covered by endothelial membrane.
MYOCARDIUM
• The myocardium is the thick middle layer of the heart wall.
• It is composed of cardiac muscle tissue.
• The thickness of the myocardium varies in accordance with the force
needed to eject blood from the particular chamber. Thus, the thickest
portion of the myocardium surrounds the left ventricle and the atrial walls
are relatively thin.
EPICARDIUM
• The epicardium is the outermost heart layer and is also known as the
visceral layer of the serous pericardium.
• The epicardium is composed of a serous membrane and areolar connective
tissue
SURFACES OF THE HEART
There are three surfaces of heart.
A: Sternocostal surface (Anterior)
Formed by Part of right atrium and the right ventricle. the left ventricle and part of the left auricle.
Atrioventricular groove seperates R.A from R.V.
Right ventricle separated from the left ventricle by the anterior interventricular groove.
B: Diaphragmatic surface
Consists of the left ventricle
Small portion of the right ventricle
This surface faces inferiorly, rests on the diaphragm.
C:The base of the heart
The base of the heart is directed posteriorly.
It consists of:
the left atrium;
a small portion of the right atrium;
the proximal parts of the great veins (superior and inferior venae cavae and the pulmonary veins)
From the base the heart projects to form apex.
CARDIAC CHAMBER
The heart functionally consists of two pumps.
• The right pump which receives deoxygenated blood from
the body and pumps it to lungs.
• The left pump which receives oxygenated blood from the
lungs pumps it to the body.
Each pump consists of an atrium and a ventricle separated
by a valve.
• On the right side there is right atrium and right ventricle.
• On left side there is left atrium and left ventricle.
SEPARATION BETWEEN THE CHAMBERS
• The atria are separated from each other by thin septum known as
intraatrial septum.
• The ventricles are separated from each other thick intraventricular
septum.
• The atria and ventricles are separated from each other by
arterioventricular valves.
• Externally on the heart surface there is grooved depression that
encircles the heart and mark the separation between atria and
ventricles and is called as coronary sulcus.
• There is an intraatrial groove beneath the aorta that separates the
left and right atia.
• The right and left ventricles are separated from each other by
interventricular groove (anterior and posterior)
RIGHT ATRIUM
• The right atrium forms the suprio-anterior surface of the heart.
• The right atrium is divided into two parts:
 The posterior – smooth walled called sinus venarum
 The anterior – rough walled – called atrium proper.
 The atrium proper has an appendage (small out pouching) – the
right auricle
• The sinus venarum and atrium proper are divided from each other by muscular
ridge called crista terminalis. On the lateral surface of atrial wall the crista
terminalis make a groove called sulcus terminalis.
• The sinus venarum is the main cavity of the atria.
• All the large veins entering the atria open into this cavity.
• The atrium proper has muscular ridges called muscular pectinati. These runs
through this chamber and enter the auricle where they make a network.
• The atrial septum has an oval depression called fossa ovalis. It is the impression of
the embryological foramen ovale.
OPENINGS OF THE RIGHT ATRIUM
The right atrium recieves three main blood vessels bringing deoxygenated
blood to the right atrium.
 The superior vena cava – returns blood from the upper parts of the
body, opens to the upper part of right atrium
 The inferior vena cava – returns blood from the lower parts of the
body (greater in diameter), opens into the lower part of the atrium.
 The coronary sinus – returns blood from the most of the heart wall,
opens between the inferior vena cava and arterioventricular orifice.
 Other than these three main openings the right atrium has numerous
small appertures which drain small veins from the heart wall to the
right atrium.
The right atrium opens into right ventricle by arterioventrcular orifice which is
gaurded by tricuspid valve.
LEFT ATRIUM
The left atrium is situated behind the right atrium forms the base or the posterior
surface of the heart.
The left atrium has two part; the main cavity and the auricle.
The walls of the right atrium are thin and the chamber is mostly smooth.
The muscular pectinati is present in auricle.
It is separated from the right atrium by intraatrial septum.
OPENINGS OF THE LEFT ATRIUM
The four pulmonary veins bringing oxygenated blood from the lungs opens into the
left auricle at its upper posterior wall surface.
The anterioinferior part of the left atrium opens into left ventricle by atrioventricular
orifice which is guarded by mitral valve.
RIGHT VENTRICLE
• The right ventricle receives deoxygenated blood from right atrium
through arterioventricular orifice and pumps it to the lungs through
pulmonary artery.
• Structurally it has an inflow part and an outflow part:
 The inflow part begins with the arterioventricular orifice projects
forward and to apex of the heart
 From the apex the cavity sharply bends upward making outflow
part at right angle with the inflow part. The outflow part of left
ventricle is called infundibulum and it is connected to the
pulmonary artery.
 The inflow and the outflow parts make right angle with each
other.
• The inflow part has rough inner surface because of the presence of the
bundles of cardiac muscles called trabeculae carneae.
• The outflow part has smooth internal surface.
• There are three types of trabeculae carneae:
 The papillary muscles which are attached to the venrticular
walls from their base and their apex are attached to the tricuspid
valves by chordea tendineae.
 Moderator bands which are attached at both end to the
ventricular walls such that they cross the ventricular cavity from
septum to the anterior wall. They are free in the middle and
have role in the conduction system of the heart.
 The third type just form muscular projection into ventricular
chamber.
• The right ventricle is divided from left ventricle by ventricular septum.
The ventricular septum bulges in to the right ventricle making it
crescentric in shape.
OPENINGS OF THE RIGHT VENTRICLE
• The right ventricle opens into pulmonary artery
which carries deoxygenated blood to the lungs.
• The pulmonary artery arises from the superior part
of outflow portion.
• This opening is guarded by pulmonary valve.
LEFT VENTRICLE
• The left ventricle receives oxygenated blood from left atrium and pumps
into the whole body through aorta.
• Like the right ventricle the left ventricle has an inflow part and an
outflow part, both making an acute angle , such that the outflow part
towers up joining the aorta.
• The outflow part of the left ventricle is called aortic vestibule.
• The walls of the left ventricle are much thicker than the right ventricle
• The left ventricle is circular in shape and is divided from right ventricle
by ventricular septum
OPENING OF THE LEFT VENTRICLE
• The left atrium opens into left atrium through atrioventruclar orifice
guarded by mitral valve.
• The left ventricle opens into the aorta. The opening is guarded by aortic
valve
CARDIAC VALVES
• There are four cardiac valves guarding openings of the
ventricles.
• Serves to prevent the backflow of the blood.
• The cardiac valves are made up of fibrous connective tissue
covered by double layer of endocardium
• What guards backflow of the blood from atria??
• The four valves are:
Two atrioventricular valves:
 The tricuspid valves (guarding right AV orifice)
 The Mitral valve (guarding the left AV junction)
 Two Semilunar valves:
 The Pulmonary valve
 The aortic valves
AV VALVES
TRICUSPID VALVE
• Guards the right AV orifice
• Made up of three cusps
• The anterior , posterior and septal
• Tied to chordae tendinae on its free surface (apex) which in turn are
connected to three pair of papillary muscles.
• Base is connected to the AV orifice by rings of fibrous tissue (cardiac
skeleton)
• Each papillary muscle pair is attached to two adjoining parts of the cusps,
which cause the whole assembly close together.
AV VALVES
Mitral valve
• Has two cusps : anterior and posterior
• Guards the left AV orifice
• Chordae tendinae attached to the margins of the cusps
• Two pairs of papillary muscles holds the cusps.
SEMILUNAR VALVES
•
•
•
•
•
•
•
•
Pulmonary valve
Guards opening of right ventricle to pulmonary trunk.
Present next to infundibulum
Opens into pulmonary trunk.
Made up of three semilunar cusps: two anterior and one posterior
The convex edge is attached to the arterial wall (no chordae tendinae),
attachment prevent prolapsing into ventricle.
The free edges have very little connective tissue.
At the root of pulmonary trunk there are three dilatations, present
external to each cusp – the sinuses.
When ventricles contract, the cusps opens into pulmonary trunk,
when ventricles relax the sinuses are filled with blood pushing the
cusps towards closure
SEMILUNAR VALVES
Aortic valve
• Guards the aortic orifice.
• Made up of three semilunar cusps: one anterior and two posterior.
• Behind each cusp there is aortic sinus present
• Structure and function is same as that of pulmonary valve
• The anterior aortic sinus gives origin to the right coronary artery,
and the left posterior sinus gives origin to the left coronary artery.
CORONARY CIRCULATION
• Nutrients cannot diffuse from the blood to all layers of myocardium,
for this reason heart has its own blood circulation called coronary
circulation consisting of coronary arteries and veins.
• Two coronary arteries, the right and left coronary arteries, branch
from the ascending aorta and encircle the heart like a crown.
RIGHT CORONARY ARTERY
• The right coronary artery arise from the anterior aortic sinus.
• It can be divided into three parts :
 The proximal portion- runs between right atrium and pulmonary
trunk- give branches and supply blood to the Infundibulum (right
ventricle) and SA node (right atrium).
 The descending portion- runs downward over the sternocoastal
surface at the anterior side of atrioventricular groove (coronary
sulcus)- give branches and supply blood to right atrium and anterior
wall of the right ventricle.
 The distal portion- curves from anterior to posterior surface of the
heart, runs upward along the posterior atrioventricular groove
(coronary sinus)- give branches and supply blood to diaphragmatic
wall of right ventricle, interventrcular septum and right atrium from
posterior side.
BRANCHES OF RCA
From the first part of RCA arise:
 Right conus artery- supplies blood conus (infundibulum) and to upper
part of anterior surface of the right ventricle.
 Artery of SA node- supplies blood to right atrium along the area of SA
node
From the second part arises:
 Anterior interventricular branches (2 or 3) supplies blood to anterior
surface of the right ventricle.
 Marginal branch- (largest one) supplies blood to the right ventricle and
runs upto apex.
From the 3rd part arise:
 Posterior interventricular branches (2 or 3)- supplies to the
diaghragmatic surface of right ventricle.
 Posterior interventricular artery (descending)- given off at the terminal
portion of RCA- runs downward and forward to the apex of the heart
in the interventricular groove and supplies the inferior/ diaphragmatic
surface of right and left ventricles.
 The atrial branches supply the atrium (lateral and anterior surfaces)
LEFT CORONARY ARTERY
• Arises from the posterior sinus of the aorta.
• It passes to the left to between pulmonary trunk and left atrium, moves
across the left auricle and then appears on the sternocostal surface of the
heart.
• It then divides into two main arteries of almost equal diameter, the
circumflex and the anterior interventricular artery.
• The circumflex branch
 runs to the left in the anterior part of the atrioventricular groove.
 It then curves around the left border, runs downward to the right,
in the posterior part of the atrioventricular groove.
 It ends here by anastamosing with terminal part of right coronary artery.
BRANCHES OF LCA
The LCA gives off following branches:
 The anterior interventricular artery/ Left anterior descending artery- runs
downward in the anterior interventrcular groove and then curves around the
apex moves upward in the posterior interventricular groove- give branches to
both ventricles and the interventricular septum. It anastamose with the posterior
interventricular artery of right coronary artery.
One of the major branches of the LAD artery is diagonal artery which supplies
the left ventricle.
 The circumflex artery- winds around the left margin of the heart in the
atrioventricular groove, giving off:
 left marginal artery- large branch that supplies the left margin of the
left ventricle down to the apex.
 Anterior ventricular and posterior ventricular branches supply the left
ventricle.
 Atrial branches supply that supply the whole left atrium.
VENUS CIRCULATION
• The deoxygenated blood from the myocardium drains into a
large vascular sinus in the coronary sulcus on the posterior
surface of the heart towards the left, called the coronary
sinus.
• The coronary sinus empties into the right atrium.
CARDIAC VEINS
• The principal tributaries carrying blood into the coronary sinus are:
 Great cardiac vein- present on the anterior interventricular sulcus (parallel to
anterior interventricular artery). It moves up along the anterior coronary
sulcus, winds around the left margin of the heart to join the coronary sinus
at the posterior atrioventricular groove. It drains the areas of the heart
supplied by the left coronary artery.
 Small cardiac vein- present on posterior right part of the coronary sulcus (runs
along the terminal part of right coronary artery) drains the right atrium
and right ventricle. Joins the coronary sinus at its terminal point.
 Middle cardiac vein- present on the inferior and posterior interventricular
sulcus runs along and drain the areas supplied by posterior interventricular
branch of right coronary artery.
• Anterior cardiac veins, which drain the right ventricle and open directly into the right
atrium.
NERVE SUPPLY TO THE HEART
• The cardiac center is present in medulla oblangata in the CNS.
• It sends both sympathetic and parasympathetic innervation to the heart.
• Sympathetic arise from cervical and thoracic portions.
• Parasympathetic arise through vagus nerve.
• Sympathetic secretes adrenaline and noradrenaline at their nerve
terminals, while parasympathetic nerves secretes acetylcholine.
• Sym
has
cardioacceleratory
cardioinhabitory properties
properties,
while
parasym
has
CONDUCTION SYSTEM OF THE HEART
The conduction system of the heart is responsible for its automatic and continuous
pumping.
It consists of:
• Sinoatrial node
• Atrioventricular node
• The Atrioventricular bundle (bundle of his)
CONDUCTION SYSTEM OF THE HEART
SA node:
• Located at the upper part of the sulcus terminalis in the wall of the right atrium.
• Responsible for spontaneous rythmatic electrical signals which spread through the
atrial muscles.
AV node:
• Located at the lower part of atrial septa just above the attachment of septal cusps
of tricuspid valve.
• Responsible for slowing down of electrical conduction from atria to ventricle.
• It allows the conduction of electrical impulse from atria to ventricle.
AV bundle
• The only connection between myocardium of ventricles and myocardium of atria.
• Descends though the fibrous skeleton of the heart, goes behind the septal cusp of
tricuspid valve and reach the interventricular septum
• At the upper part of muscular portion of the interventricular septum divides into
RBB and LBB each supplying to the corresponding ventricle.
• The bundle branches join the pukinje fibers of the ventricles.