✓Heart ✓Anatomy of heart ✓Blood circulation ✓Blood Vessels ✓Structure and function of artery, vein and capillaries ✓Elements of conduction system of heart and heart beat ✓Its regulation by nervous system ✓Cardiac output ✓Cardiac cycle ✓Regulation of bood pressure ✓Pulse ✓Electrocardiogram ✓Disorder of heart

1. Cardiovascular System
By
Yogeshwary M. Bhongade
Assistant Professor
Kamla Neharu College of Pharmacy, Butibori, Nagpur

2. Contents
✓Heart
✓Anatomy of heart
✓Blood circulation
✓Blood Vessels
✓Structure and function of artery, vein and capillaries
✓Elements of conduction system of heart and heart beat
✓Its regulation by nervous system
✓Cardiac output
✓Cardiac cycle
✓Regulation of bood pressure
✓Pulse
✓Electrocardiogram
✓Disorder of heart

3. Heart

4. Structure of Heart
• Mascular organ containing 4
chemberes
• Location- Left of the middle of
thoracic cavity, resting on diphragm
• Shape- Hallow or cone shape
• Upper 2 chembers (Atria) -
Interatrial septums
• Lower 2 chember (Ventricles)-
Interventricular septums
• Weight- 250- 350gm
• Diameter- 14cm long (Average
adult)
• Width- 9cm

5. Layers of heart
• The heart wall is composed of connective
tissue, endothelium, and cardiac muscle. It is
the cardiac muscle that enables the heart to
contract and allows for the synchronization
of the heartbeat. The heart wall is divided
into three layers: epicardium, myocardium,
and endocardium.
1. Epicardium (Pericardium): the outer
protective layer of the heart.
2. Myocardium: muscular middle layer wall
of the heart.
3. Endocardium: the inner layer of the heart.

6. Epicardium/ Visceral Pericardium
• Epicardium (epi-cardium) is the outer layer of the heart wall. It is also
known as visceral pericardium as it forms the inner layer of the
pericardium. The epicardium is composed primarily of loose
connective tissue, including elastic fibers and adipose tissue. The
epicardium functions to protect the inner heart layers and also assists
in the production of pericardial fluid. This fluid fills the pericardial
cavity and helps to reduce friction between pericardial membranes.
Also found in this heart layer are the coronary blood vessels, which
supply the heart wall with blood. The inner layer of the epicardium is
in direct contact with the myocardium.

7. Myocardium
• Myocardium (myo-cardium) is the middle layer of the heart wall. It is
composed of cardiac muscle fibers, which enable heart contractions. The
myocardium is the thickest layer of the heart wall, with its thickness varying
in different parts of the heart. The myocardium of the left ventricle is the
thickest, as this ventricle is responsible for generating the power needed to
pump oxygenated blood from the heart to the rest of the body. Cardiac
muscle contractions are under the control of the peripheral nervous system,
which directs involuntary functions including heart rate.
• Cardiac conduction is made possible by specialized myocardial muscle
fibers. These fiber bundles, consisting of the atrioventricular bundle and
Purkinje fibers, carry electrical impulses down the center of the heart to the
ventricles. These impulses trigger the muscle fibers in the ventricles to
contract.

8. Endocardium
• Endocardium (endo-cardium) is the thin inner layer of the heart wall.
This layer lines the inner heart chambers, covers heart valves, and is
continuous with the endothelium of large blood vessels. The
endocardium of heart atria consists of smooth muscle, as well as
elastic fibers. An infection of the endocardium can lead to a condition
known as endocarditis. Endocarditis is typically the result of an
infection of the heart valves or endocardium by certain bacteria, fungi,
or other microbes. Endocarditis is a serious condition that can be fatal.

9. Chembers of Heart
• The heart consists of four chambers in which blood flows. Blood
enters the right atrium and passes through the right ventricle. The right
ventricle pumps the blood to the lungs where it becomes oxygenated.
The oxygenated blood is brought back to the heart by the pulmonary
veins which enter the left atrium. From the left atrium blood flows into
the left ventricle. The left ventricle pumps the blood to the aorta which
will distribute the oxygenated blood to all parts of the body.

10. Valve of Heart
• The heart has four valves - one for each chamber
of the heart. The valves keep blood moving
through the heart in the right direction.
1. Mitral valve
2. Tricuspid valve
3. Aortic valve
4. Pulmonic valve
• The mitral valve and tricuspid valve are located
between the atria (upper heart chambers) and the
ventricles (lower heart chambers).
• The aortic valve and pulmonic valve are located
between the ventricles and the major blood
vessels leaving the heart.

12. Blood circulation
The right and left sides of the heart work together.
Right side of the heart
• Blood enters the heart through two large veins, the inferior and superior vena
cava, emptying oxygen-poor blood from the body into the right atrium of the
heart.
• As the atrium contracts, blood flows from your right atrium into your right
ventricle through the open tricuspid valve.
• When the ventricle is full, the tricuspid valve shuts. This prevents blood from
flowing backward into the atria while the ventricle contracts.
• • As the ventricle contracts, blood leaves the heart through the pulmonic valve,
into the pulmonary artery and to the lungs where it is oxygenated. Note that
oxygen-poor or CO2 containing blood goes through the pulmonary artery to
the lungs where CO2 is exchanged for O2.

13. Left side of the heart (operating at the same time as the right side of
the heart)
• The pulmonary vein empties oxygen-rich blood from the lungs into
the left atrium of the heart.
• As the atrium contracts, blood flows from your left atrium into your
left ventricle through the open mitral valve.
• When the ventricle is full, the mitral valve shuts. This prevents blood
from flowing backward into the atrium while the ventricle contracts.
• As the ventricle contracts, oxygen-enriched blood leaves the heart
through the aortic valve, into the aorta and to the arteries and
eventually into veins to complete the blood circulation in your body.

15. Conduction system of heart
• Mad up of specialized cardiac muscle fibres and is responsible for
initiation and conduction of cardiac impulses.
• The cardiac conduction system is a collection of nodes and specialised
conduction cells that initiate and co-ordinate contraction of the heart
muscle. It consists of:
• Sinoatrial node
• Atrioventricular node
• Atrioventricular bundle (bundle of His)
• Purkinje fibres

16. • The sequence of electrical events during one
full contraction of the heart muscle:
• An excitation signal (an action potential) is
created by the sinoatrial (SA) node.
• The wave of excitation spreads across the
atria, causing them to contract.
• Upon reaching the atrioventricular (AV)
node, the signal is delayed.
• It is then conducted into the bundle of His,
down the interventricular septum.
• The bundle of His and the Purkinje fibres
spread the wave impulses along the
ventricles, causing them to contract.

17. Sinoatrial Node
• The sinoatrial (SA) node is a collection of specialised cells (pacemaker cells),
and is located in the upper wall of the right atrium, at the junction where the
superior vena cava enters.
• These pacemaker cells can spontaneously generate electrical impulses. The
wave of excitation created by the SA node spreads via gap junctions across
both atria, resulting in atrial contraction (atrial systole) – with blood moving
from the atria into the ventricles.
• The rate at which the SA node generates impulses is influenced by the
autonomic nervous system:
• Sympathetic nervous system – increases firing rate of the SA node, and thus
increases heart rate.
• Parasympathetic nervous system – decreases firing rate of the SA node, and
thus decreases heart rate.

18. Atrioventricular Node
• After the electrical impulses spread across the atria, they converge at the
atrioventricular node – located within the atrioventricular septum, near the
opening of the coronary sinus.
• The AV node acts to delay the impulses by approximately 120ms, to
ensure the atria have enough time to fully eject blood into the ventricles
before ventricular systole.
• The wave of excitation then passes from the atrioventricular node into the
atrioventricular bundle.

19. Atrioventricular Bundle
• The atrioventricular bundle (bundle of His) is a continuation of the
specialised tissue of the AV node, and serves to transmit the electrical
impulse from the AV node to the Purkinje fibres of the ventricles.
• It descends down the membranous part of the interventricular septum,
before dividing into two main bundles:
• Right bundle branch – conducts the impulse to the Purkinje fibres of
the right ventricle
• Left bundle branch – conducts the impulse to the Purkinje fibres of the
left ventricle.

20. Purkinje Fibres
• The Purkinje fibres (sub-endocardial plexus of conduction cells) are a
network of specialised cells. They are abundant with glycogen and have
extensive gap junctions.
• These cells are located in the subendocardial surface of the ventricular
walls, and are able to rapidly transmit cardiac action potentials from the
atrioventricular bundle to the myocardium of the ventricles.
• This rapid conduction allows coordinated ventricular contraction
(ventricular systole) and blood is moved from the right and left ventricles
to the pulmonary artery and aorta respectively.

21. Blood Vessels
• Blood vessels are the channels or conduits through which blood is
distributed to body tissues. The vessels make up two closed systems of
tubes that begin and end at the heart. One system, the pulmonary vessels,
transports blood from the right ventricle to the lungs and back to the left
atrium. The other system, the systemic vessels, carries blood from the left
ventricle to the tissues in all parts of the body and then returns the blood to
the right atrium. Based on their structure and function, blood vessels are
classified as either arteries, capillaries, or veins.

22. Electrocardiogram
• Electrical activities of the heart is recorded in the forn of ECGor EKG.
• It is composite of recording of all action potential produced by the nodes an cell of
myocardium.
• Each wave oe segment of ECG corrsponds to certain events of cardiac cycle.

23. Artery
• An artery is an elastic blood vessel
that transports blood away from the
heart.
• This is the opposite function of veins,
which transport blood to the heart.
Arteries are components of the
cardiovascular system.
• This system circulates nutrients to and
removes waste material from the cells
of the body.

24. Types of Arteries
• There are two main types of arteries:
1. Pulmonary arteries and
2. Systemic arteries.
• Pulmonary arteries carry blood from the heart to the lungs where the
blood picks up oxygen. The oxygen-rich blood is then returned to the heart
via the pulmonary veins.
• Systemic arteries deliver blood to the rest of the body. The aorta is the
main systemic artery and the largest artery of the body. It originates from
the heart and branches out into smaller arteries which supply blood to the
head region (brachiocephalic artery), the heart itself (coronary arteries), and
the lower regions of the body

25. • The smallest arteries are called arterioles and they play a vital role in
microcirculation.
• Microcirculation deals with the circulation of blood from arterioles to
capillaries to venules (the smallest veins).
• The liver, spleen and bone marrow contain vessel structures called
sinusoids instead of capillaries.
• In these structures, blood flows from arterioles to sinusoids to venules.​

26. Structure of Artery
• The artery wall consists of three layers:
• Tunica Adventitia (Externa)- the strong outer covering
of arteries and veins. It is composed of connective tissue
as well as collagen and elastic fibers. These fibers allow
the arteries and veins to stretch to prevent over
expansion due to the pressure that is exerted on the
walls by blood flow.
• Tunica Media - the middle layer of the walls of arteries
and veins. It is composed of smooth muscle and elastic
fibers. This layer is thicker in arteries than in veins.
• Tunica Intima - the inner layer of arteries and veins. In
arteries, this layer is composed of an elastic membrane
lining and smooth endothelium (a special type of
epithelial tissue) that is covered by elastic tissues.

27. • Capillaries
• Capillaries, the smallest and most
numerous of the blood vessels,
form the connection between the
vessels that carry blood away from
the heart (arteries) and the vessels
that return blood to the heart
(veins). The primary function of
capillaries is the exchange of
materials between the blood and
tissue cells.

28. • Capillary distribution varies with the metabolic activity of body tissues.
Tissues such as skeletal muscle, liver, and kidney have extensive capillary
networks because they are metabolically active and require an abundant
supply of oxygen and nutrients. Other tissues, such as connective tissue,
have a less abundant supply of capillaries. The epidermis of the skin and the
lens and cornea of the eye completely lack a capillary network. About 5
percent of the total blood volume is in the systemic capillaries at any given
time. Another 10 percent is in the lungs.
• Smooth muscle cells in the arterioles where they branch to form capillaries
regulate blood flow from the arterioles into the capillaries.

29. • Veins
• Veins carry blood toward the heart. After blood passes through the
capillaries, it enters the smallest veins, called venules. From the
venules, it flows into progressively larger and larger veins until it
reaches the heart. In the pulmonary circuit, the pulmonary veins
transport blood from the lungs to the left atrium of the heart. This
blood has a high oxygen content because it has just been oxygenated
in the lungs. Systemic veins transport blood from the body tissue to
the right atrium of the heart. This blood has a reduced oxygen content
because the oxygen has been used for metabolic activities in the tissue
cells.

30. • The walls of veins have the same three layers as the arteries. Although
all the layers are present, there is less smooth muscle and connective
tissue. This makes the walls of veins thinner than those of arteries,
which is related to the fact that blood in the veins has less pressure
than in the arteries. Because the walls of the veins are thinner and less
rigid than arteries, veins can hold more blood. Almost 70 percent of
the total blood volume is in the veins at any given time. Medium and
large veins have venous valves, similar to the semilunar valves
associated with the heart, that help keep the blood flowing toward the
heart. Venous valves are especially important in the arms and legs,
where they prevent the backflow of blood in response to the pull of
gravity.