By:M. Thiru murugan Unit – IV: Heart : Structure, functions including conduction system & cardiac cycle Blood vessels : Types, Structure and position Circulation of blood Blood pressure and pulse Heart The circulatory system: It consisting of blood, blood vessels, and heart. This supplies oxygen and other nutrients, Transports hormones Removes unnecessary waste products. Heart and its Structure The heart is a muscular organ about the size of a fist, located in mediastinum just behind and slightly left of the breastbone (sternum). The heart pumps blood through the blood vessels (arteries and veins called the cardiovascular system). Structure of heart: Layers of the heart (3) Chambers of the heart (4) Valves of the heart (4) Blood vessels of the heart (5) 3 layers of the heart: Epicardium/pericardium: outer protective layer of the heart. Visceral and parietal (pericardial fluid). Protection for the heart and big vessels and prevent collapse of heart, Myocardium: muscular middle layer wall of the heart. Responsible for keeping the heart pumping blood around the body. Endocardium: the inner layer of the heart. Regulate blood flow through the chambers of the heart and pass the electrical impulses Chambers of the heart: The atria: These are the 2 upper chambers, which receive blood. RA / LA The ventricles: These are the 2 lower chambers, which discharge blood. RV/ LV A wall of tissue called the septum separates the left and right atria called atrial septum and the left and right ventricle called ventricular septum. Valves in the heart: There are four valves Two-atrio ventricular valves: The 2 types: bicuspid (mitral) - LA & LV, and tricuspid valves - RA & RV. Two-semilunar valves: The aortic valves and the pulmonary valve. Major blood vessels of the heart There are 5 major blood vessels Pulmonary artery Pulmonary veins Aorta[artery] Inferior vena cava [IVC] veins Superior vena cava [SVC] veins Functions of heart: Pumping oxygenated blood to the body parts. Pumping nutrients and other vital substances Receiving deoxygenated blood and carrying metabolic waste products from the body Pumping deoxygenated blood to the lungs for oxygenation. Maintaining blood pressure. Conduction system The electrical conduction system that controls the heart rate. This system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood. The electrical pulses determine the order in which the chambers contract & the heart rate Conductive system consist of: SA Node AV Node Bundle of his or His Bundles – bundle of branches ( right and left) 4. Purkinje fibres Sinoatrial node (SA) : also known as the pace maker of the heart and Located in the upper wall of the right atrium Made up of both muscle and nervous tissue Here the electrical impulse begins Atrioventricular (AV) node: located between the atria and ventricles of the heart The electrical impulse is carried fr

1. By:
M. Thiru murugan
The Circulatory
System

2. Unit – IV:
a)Heart : Structure, functions including conduction system
& cardiac cycle
b)Blood vessels : Types, Structure and position
c)Circulation of blood
d)Blood pressure and pulse

3. Heart
The circulatory system:
•It consisting of blood, blood vessels, and
heart.
•This supplies oxygen and other nutrients,
•Transports hormones
•Removes unnecessary waste products.

4. Heart and its Structure
• The heart is a muscular organ about the size of a fist,
• located in mediastinum just behind and slightly left of the
breastbone (sternum).
• The heart pumps blood through the blood vessels (arteries
and veins called the cardiovascular system).
Structure of heart:
• Layers of the heart (3)
• Chambers of the heart (4)
• Valves of the heart (4)
• Blood vessels of the heart (5)

6. 3 layers of the heart:
• Epicardium/pericardium:
outer protective layer of the heart.
Visceral and parietal (pericardial fluid).
Protection for the heart and big vessels
and prevent collapse of heart,
• Myocardium: muscular middle layer wall
of the heart. Responsible for keeping the heart
pumping blood around the body.
• Endocardium: the inner layer of the heart.
Regulate blood flow through the chambers
of the heart and pass the electrical impulses

7. Chambers of the heart:
• The atria: These are the 2 upper
chambers, which receive blood.
RA / LA
• The ventricles: These are the 2
lower chambers, which discharge
blood. RV/ LV
• A wall of tissue called the septum
separates the left and right atria
called atrial septum and the left
and right ventricle called
ventricular septum.

8. Valves in the heart:
• There are four valves
• Two-atrio ventricular
valves: The 2 types: bicuspid
(mitral) - LA & LV,
and tricuspid valves - RA &
RV.
• Two-semilunar valves:
The aortic valves and
the pulmonary valve.

9. Major blood vessels of the heart
• There are 5 major blood
vessels
1. Pulmonary artery
2. Pulmonary veins
3. Aorta[artery]
4. Inferior vena cava [IVC]
veins
5. Superior vena cava [SVC]
veins

10. Functions of heart:
1. Pumping oxygenated blood to the body parts.
2. Pumping nutrients and other vital substances
3. Receiving deoxygenated blood and carrying
metabolic waste products from the body
4. Pumping deoxygenated blood to the lungs for
oxygenation.
5. Maintaining blood pressure.

11. Conduction system
•The electrical conduction system that controls
the heart rate.
•This system generates electrical impulses and
conducts them throughout the muscle of the heart,
stimulating the heart to contract and pump blood.
•The electrical pulses determine the order in which
the chambers contract & the heart rate

13. Conductive system consist of:
1. SA Node
2. AV Node
3. Bundle of his or His Bundles – bundle of branches
( right and left)
4. Purkinje fibres

14. •Sinoatrial node (SA) : also known as the pace
maker of the heart and Located in the upper wall of
the right atrium
•Made up of both muscle and nervous tissue
•Here the electrical impulse begins
•Atrioventricular (AV) node:
•located between the atria and ventricles of the
heart
•The electrical impulse is carried from the SA node,
and the AV node is stimulated.

15. Atrioventricular bundle branches:
• Atrioventricular bundle branches: are located
between the atria and the ventricles.
• Fibers branch into 2 bundles -left and right side of the
heart
• The electrical impulse travels from the AV node to the
bundle branches after the atria have contracted and
emptied.
• The AV bundle branches then carry the impulses down
the center of the heart to the left and right ventricles

16. • AV bundles start to divide
further into: purkinje fibers
• Purkinje fibres: located at the
end of the AV bundle
branches, at the base of the
heart
• the Purkinje fibers are
responsible for the
contraction of the ventricles

17. Cardiac cycle
• The cardiac cycle is defined as a sequence of alternating
contraction and relaxation of
the atria and ventricles in order to pump blood
throughout the body.
Phases:
Diastolic phase (also called diastole).
Systolic phase (also called systole)
• Both the atria and the ventricles undergo alternating
states of systole and diastole.

18. Cardiac cycle
Phases:
Diastolic phase (also called diastole) where the heart
chamber is in a state of relaxation and fills with blood
that receives from the veins.
Systolic phase (also called systole) where the heart
chambers are contracting and pumps the blood.
• In other words, when the atria are in diastole (relax),
the ventricles are in systole (contract) and ventricles
are in diastole (relax), atria are in systole (contract)

19. • Atrial Diastole: In this stage, chambers of the heart are
relaxed.
• Atrial Systole: atrium contracts. Blood pass from atrium to
ventricle
• Isovolumic Contraction: At this stage, ventricles begin to
contract.
• Ventricular Ejection: Here ventricles contract.
• Isovolumic Relaxation: ventricles stop contracting and
begin to relax.
• Ventricular Filling Stage: In this stage, blood flows from
atria into the ventricles.
Cardiac cycle

20. • Heartbeat 72 beats/minute, duration of
each cardiac cycle will be 0.8 seconds.
• Duration of cardiac cycle:
• Atrial systole: continues for about 0.1
seconds
• Ventricular systole: continues for
about 0.3 seconds
• Complete cardiac diastole: continues
for about 0.4seconds
• Heart sounds:
• ECG:
Cardiac cycle

21. Blood vessels:
• Blood vessels are the channels or tubes like structures
through which blood is circulated in our body.
Types:
Based on their structure and function, blood vessels are
classified as
1. Arteries
2. Veins
3. Capillaries

22. ARTERIES
ARTERIOLES
CAPILLARIES
VENULES
VEINS

23. Arteries
• Arteries carry blood away from the heart.
• Pulmonary arteries transport deoxygenated blood from
the RV to the lungs.
• Systemic arteries transport oxygenated blood from the
LV to the body tissues.
• Blood is pumped from the ventricles into large arteries that
branch repeatedly into smaller and smaller arteries until the
branching results in microscopic arteries called arterioles.
• The arterioles play a key role in regulating blood flow into
the tissue capillaries.

24. Veins
• Veins carry blood toward the heart and the smallest veins,
called venules.
• From the venules, it flows into progressively larger and
larger veins until it reaches the heart.
• Pulmonary veins transport blood from the lungs to the left
atrium of the heart.
• Systemic veins transport blood from the body tissue to the RA
of the heart.
• This blood has a reduced oxygen content because the oxygen
has been used for metabolic activities in the tissue cells.

25. Capillaries
•Capillaries, the smallest and
most numerous of the blood
vessels,
•Form the connection between
the arteries and veins.
•The primary function of
capillaries is the exchange of
materials between the blood
and tissue cells.

26. Structure of blood vessels
• The wall of an artery & Vein consists of 3 layers.
• The innermost layer, the tunica intima (tunica interna)
• The middle layer, the tunica media
• The outermost layer, tunica externa or tunica adventitia

27. Circulation of blood
• The continuous movement of blood through the
heart and blood vessels
• Types:
• It includes:
1. Pulmonary circulation
2. Systemic circulation

28. Pulmonary circulation
• The supply of deoxygenated blood from the heart to the lungs for
purification.
• The inferior and superior vena cava carry deoxygenated
blood to the relaxed right atrium of the heart
• The right atrium contracts and blood travels through the
tricuspid valve into the relaxed right ventricle
• The right ventricle contracts, the blood is pumped through the
pulmonary valve into the pulmonary artery to the lungs
• The return of oxygenated blood from lungs to the heart via
the pulmonary vein after purification

29. Systemic circulation
• The supply of oxygen-rich blood from the heart to the
body cells.
• Oxygen rich blood travels from the lungs via the
pulmonary veins to the left atrium
• The left atrium contracts, and blood flows through the
mitral valve into the relaxed left ventricle
• The strong left ventricle contracts and pumps oxygen rich
blood through the aortic valve into the aorta
• The aorta carries blood to the organs of the body

30. Blood pressure
Definition : blood pressure can be defined as the pressure
exerted by the moving blood on the walls of the arteries.
Normal Values: Normal Adult range Systolic /diastolic –
120/80 to 140/90 mmhg
• Systolic and diastolic
• Systolic B.P (S.B.P) Defined as the maximum B.P in the
arteries Attainable during systole. Normal 120 + 20 mm Hg.
• DIASTOLIC B.P (D.B.P) Def--- as the minimum pressure
that is obtained at the end of the ventricular diastole. Normal
range 80 -90 mm Hg

31. Methods
1. Palpatory method
2. Auscultatory method
Measurement device:
Sphygmomanometer
Types:
Steps / procedure /
technique of checking Bp

32. Factors affecting blood pressure
Disease
Age
Heredity
Blood Volume
Weight
Diet
Hormones
Salt
Caffeine
Environmental factors
Psychological factors
Stress/Anxiety
Gravity
Drugs
Alcohol
Time of day

33. Abnormal BP
•Hypertension
•Hypotension

34. Pulse
•DEFINITION:
•It is the rate of heart beats. Pulse is
actually called heart rate, which is
the number of time heart beats each
minutes.

37. Characteristics
1. Rate
2. Rhythm
3. Volume
4. Tension
• Steps:
• Abnormal pulse:
Tachycardia
Bradycardia