The circulatory system transports blood, nutrients, gases, hormones, and waste products throughout the body. It consists of the heart, blood vessels, and blood. The heart pumps blood through two main circuits - the pulmonary circuit, which carries deoxygenated blood to the lungs and returns oxygenated blood, and the systemic circuit, which pumps oxygenated blood to the entire body and returns deoxygenated blood back to the heart. The cardiovascular system is further divided into four chambers, two atria that receive blood and two ventricles that pump blood out of the heart. Blood contains red blood cells, white blood cells, platelets, and plasma and comes in four main blood groups - A, B, AB, and

1. THE
HEART
Physiology of circulatory system
Prepared By;
Laxmi s kamat
Lecturer
KAHER INS Belagavi

2. INTRODUCTION
 The cardiovascular system is
transport system of body
 It comprises blood, heart and
blood vessels.
 The system supplies nutrients
to and remove waste
products from various tissue
of body.
 The conveying media is liquid
in form of blood which flows
in close tubular system.

3. FUNCTION OF CARDIOVASCULAR SYSTEM

4. • Protection – protects against blood loss from injury and
against pathogens, including foreign microbes and toxins
introduced into the body.
These substances can be categorized as follows:
• Clotting– prevents blood loss when blood vessels are
damaged
• Immune function - protect against many disease-
causing agents (pathogens). Performed by leukocytes
(white blood cells).

5. Major Components of the Circulatory System
Cardiovascular system
consist of:
• Heart
• Blood
• Blood vessels: form a
tubular network that
permits the flow of
blood
• Arteries,
arterioles, veins,
capillaries
Lymphatic system
consists of:
• Lymphatic vessels
• Lymphoid tissues
• Found in the spleen,
thymus, tonsil and
lymph nodes
• The circulatory system is divided into two major
subdivisions:
• The Cardiovascular system and the Lymphatic system

7. Composition of blood:
1.Solid component (Blood cells)


41% of total volume
Red blood cells (erythrocytes), white blood
cells (leukocytes), or platelets (thrombocytes)
2.Liquid Component (Blood plasma)
• 55% of total blood volume
• Composed of 91.5% water and 8.5%
of nutrients, waste products, proteins,
enzymes and hormones
• Straw coloured or yellowy solution
• Nutrients from the small intestine is
absorbed into the plasma and
transported around the body
3. Platelet

8. Composition of Blood

10. PLATELETS
• Small colour-less bodies that usually appear
as irregular spindles or discs that are much
smaller than RBC and WBC
• Produced in red bone marrow
• Life cycle is approximately 5 to 9 days
• Platelets are involved in the process of clotting
and they help to repair slightly damaged blood
vessels

11. WHITE BLOOD CELLS
• Slightly larger than red blood cells
• Classified according to the presence or absence of granules(tiny sacs)
in their cytoplasm
• Life cycle is from a few hours to a few days
• Produced in bone marrow and lymph tissue
• They move to areas of infection or disease to engulf invading bodies
(puss is the accumulation of WBC)

13. Blood cell formation,
• Also called hematopoiesis, or hemopoiesis,
• Continuous process by which the
cellular constituents of blood are replenished as needed.
• Blood cells are divided into three groups: the red blood cells
(erythrocytes), the white blood cells (leukocytes), and the
blood platelets (thrombocytes).
• The white blood cells are subdivided into three broad groups:
granulocytes and agranulocytes.

15. • Blood cells do not originate in the bloodstream itself but
in specific blood-forming organs, notably the marrow of
certain bones.
• In the human embryo, the first site of blood formation is
the yolk sac.
• Later in embryonic life, the liver becomes the most
important red blood cell-forming organ, but it is soon
succeeded by the bone marrow, which in adult life is the
only source of both red blood cells and the granulocytes.

16. • In the human adult, the bone marrow produces all of the red blood
cells, 60–70 percent of the white cells (i.e., the granulocytes), and
all of the platelets.
• The lymphatic tissues, particularly the thymus, the spleen, and
the lymph nodes, produce the lymphocytes (comprising 20–30
percent of the white cells).
• The reticuloendothelial tissues of the spleen, liver, lymph nodes,
and other organs produce the monocytes (4–8 percent of the white
cells).
• The platelets, which are small cellular fragments rather than
complete cells, are formed from bits of the cytoplasm of the giant
cells (megakaryocytes) of the bone marrow.

17. • In a normal adult the red cells of about half a litre (almost one
pint) of blood are produced by the bone marrow every week.
• Almost 1 percent of the body’s red cells are generated each day,
• The balance between red cell production and the removal of aging
red cells from the circulation is precisely maintained.
• The rate of blood cell formation varies depending on the
individual, but a typical production might average
200,000,000,000 red cells per day, 10,000,000,000 white cells per
day, and 400,000,000,000 platelets per day.

18. • A blood type (also called a blood group) is a classification of
blood, based on the presence and absence of antibodies and
inherited antigenic substances on the surface of red blood cells
(RBCs).
BLOOD GROUPING

19. History of Blood Groups and Blood Transfusions
•Experiments with blood transfusions
have been carried out for hundreds of
years. Many patients have died and it was
not until 1901, when the Austrian Karl
Landsteiner discovered human blood
groups, that blood transfusions became
safer.
•He found that mixing blood from two
individuals can lead to blood clumping.
The clumped RBCs can crack and cause
toxic reactions. This can be fatal.
http://nobelprize.org/medicine/educational/landsteiner/readmore.html

20. History of Blood Groups and Blood
Transfusions (Cont.)
•Karl Landsteiner discovered that blood
clumping was an immunological reaction
which occurs when the receiver of a blood
transfusion has antibodies against the donor
blood cells.
•Karl Landsteiner's work made it possible to
determine blood types and thus paved the
way for blood transfusions to be carried out
safely. For this discovery he was awarded the
Nobel Prize in Physiology or Medicine in
1930.

21. Of What is Blood Made?
An adult human has about 4–6 liters of
blood circulating in the body.
Blood consists of several types of cells
floating around in a fluid called plasma.
The red blood cells (RBCs) contain
haemoglobin, a protein that binds oxygen.
RBCs transport oxygen to, and remove
carbon dioxide from the tissues.
The white blood cells fight infection.
The platelets help the blood to clot, if you
get a wound for example.
The plasma contains salts and various
kinds of proteins.

22. •The differences in human blood are due to the
presence or absence of certain protein molecules
called antigens and antibodies.
•The antigens are located on the surface of the
RBCs and the antibodies are in the blood
plasma.
•Individuals have different types and
combinations of these molecules.
•The blood group you belong to depends on
what you have inherited from your parents.
What are the different blood groups?

23. •There are more than 20 genetically determined
blood group systems known today
•The AB0 and Rhesus (Rh) systems are the
most important ones used for blood transfusions.
•Not all blood groups are compatible with each
other. Mixing incompatible blood groups leads to
blood clumping or agglutination, which is
dangerous for individuals.
What are the different blood groups?

24. According to the ABO blood
typing system there are four
different kinds of blood types:
A, B, AB or O (null).

27. Blood Types

28. There is an agglutination reaction between similar antigen and antibody (for
example, antigen A agglutinates the antibody A and antigen B agglutinates
the antibody B). Thus, transfusion can be considered safe as long as the
serum of the recipient does not contain antibodies for the blood cell antigens
of the donor.
Note:

29. Blood group A
If you belong to the blood
group A, you have A
antigens on the surface of
your RBCs and B
antibodies in your blood
plasma.
Blood group B
If you belong to the blood
group B, you have B
antigens on the surface of
your RBCs and A
antibodies in your blood
plasma.
AB0 blood grouping system

30. Blood group AB
If you belong to the blood group
AB, you have both A and B
antigens on the surface of your
RBCs and no A or B antibodies
at all in your blood plasma.
Blood group O
If you belong to the blood group O
(null), you have neither A or B
antigens on the surface of your RBCs
but you have both A and B antibodies
in your blood plasma.

31. Well, it gets more complicated here, because there's
another antigen to be considered - the Rh antigen.
Some of us have it, some of us don't.
If it is present, the blood is RhD positive, if not it's RhD
negative.
So, for example, some people in group A will have it, and
will therefore be classed as A+ (or A positive).
While the ones that don't, are A- (or A negative).
And so it goes for groups B, AB and O.
The Rhesus (Rh) System

32. The Rhesus (Rh) System (Cont.)
•Rh antigens are transmembrane proteins with loops
exposed at the surface of red blood cells.
•They appear to be used for the transport of carbon
dioxide and/or ammonia across the plasma membrane.
•They are named for the rhesus monkey in which they
were first discovered.
•RBCs that are "Rh positive" express the antigen
designated D.
•85% of the population is RhD positive, the other 15% of
the population is running around with RhD negative
blood.

33. According to above
blood grouping systems,
you can belong to either
of following 8 blood
groups:
Do you know which blood group you
belong to?

34. •A person with Rh- blood can develop Rh antibodies
in the blood plasma if he or she receives blood from a
person with Rh+ blood, whose Rh antigens can trigger
the production of Rh antibodies.
•A person with Rh+ blood can receive blood from a
person with Rh- blood without any problems.

35. Several methods for testing the ABO group of an
individual exist. The most common method is:
Serology: This is a direct detection of the ABO
antigens. It is the main method used in blood
transfusion centres and hospital blood banks.
This form of testing involves two components:
a)Antibodies that are specific at detecting a
particular ABO antigen on RBCs.
b)Cells that are of a known ABO group that
are agglutinated by the naturally occurring
antibodies in the person's serum.

37. Blood transfusions – who can
receive blood from
whom?
People with blood group O
are called "universal
donors" and people with
blood group AB are called
"universal receivers."

41. • Heart is a four chambered, hollow muscular organ
approximately the size of your fist
• Located in the thoracic cavity in the mediastinum,
between the lungs and deep to the sternum
• Contains four chamber
• Its about the size of a fist, the hollow, cone-shaped
• There is a layer of dense connective tissues b/t the
atria and ventricle
The Heart Structure

43. FUNCTIONS OF THE HEART
• Generating blood pressure
• Routing blood
Heart separates pulmonary and systemic
circulations
• Ensuring one-way blood flow
Heart valves ensure one-way flow
• Regulating blood supply
Changes in contraction rate and force match
blood delivery to changing metabolic needs

44. Blood Circulation
• Movement of blood through the vessels of the body that
is induced by the pumping action of the heart and serves
to distribute oxygen to and remove wasted products from
all parts of the body
• Two (2) types:
• Pulmonary circulation
• Systemic circulation

45. Blood Circulation Cont’d…
• Pulmonary circuit carries deoxygenated blood away from the
heart to the lungs and returns oxygenated blood to the heart
• Systemic circuit carries oxygenated blood away from the heart to
body system and returns deoxygenated blood to the heart
• Pulmonary circuit begins in the right atrium and ends in
the right ventricle
• Systemic circuit beings in the left ventricle and ends in the
right atrium

48. Valves of the Heart: Atrioventricular Valves
• Found between the atria and ventricles
• Constitutes;
• Tricuspid valve
• Bicuspid valve
Tricuspid
valve
Bicuspid
valve
AV Valves
• Bicuspid valves: left AV valve that prevents
blood from flowing back into the left
atrium when the left ventricle contract.
• Tricuspid valve: right AV valve that
prevents blood from flowing back into the
right atrium when the right ventricle
contract. It has three flaps of tissues

49. Valves of the Heart: Semilunar Valves
• Shaped like half moons
• Constitutes;
• Pulmonary valve
• Aortic valve
• Aortic valve: beginning of the
aorta. Prevents blood from
flowing back into the left
ventricle
Aortic
valve
Pulmonary
valve • Pulmonary valve: beginning
of the pulmonary truck.
Prevents blood from flowing
back into the right ventricle

50. Pathway of Blood Flow Through the Heart

51. The Cardiac Cycle
• Cardiac cycle refers to the repeating patterns of contraction and relaxation of
the heart. The phase of contraction is called systole, and the phase of
relaxation is called diastole
• One heartbeat = one cardiac cycle
 Atria contract and relax
 Ventricles contract and relax
• Right atrium contracts (1st Diastole)
• Tricuspid valve opens
• Blood fills right ventricle
• Right ventricle contracts (1st Systole)
• Tricuspid valve closes
• Pulmonary semilunar valve opens
• Blood flows into pulmonary artery
• Left atrium contracts (2nd Diastole)
• Bicuspid valve opens
• Blood fills left ventricle
• Left ventricle contracts (2nd Systole)
• Bicuspid valve closes
• Aortic semilunar valve opens
• Blood pushed into aorta

52. Cardiac Output
• Defined as the amount of blood each ventricle pumps out
per minute.
• Determined by:
• Stroke volume – amount of blood that each ventricle
pumps out per beat
• Heart rate – number of times the heart beats in one
minute
• Cardiac Output = Heart rate X Stroke volume

53. • Normal resting stroke volume = 70 mL of blood
• Normal resting heart rate = 70-72 beats per minute
• When one factor changes, the body regulates the other factor to enhance the
cardiac output.
• Normal cardiac output = 4.9-5.4 L/min (based on the body
size of an individual)
• Normal physiological Resting Cardiac Output – 5 L/min
• When the body begins to move, the cardiac output increases
so as to enhance blood flow to the muscles.

54. Heart Sounds
• There are 4 heart sounds, 3 normal, 2 of which
are easily heard
• The 4th heart sound may normally be heard in a
young child, but is abnormal in adults
• The 1st and 2nd heart sounds are associated
with the closure of valves

55.  1st Heart Sound(Lubb)
• When the ventricle contract, the tricuspid and
bicuspid valves snap shut
 2nd Heart Sound(Dubb)
• When the atria contract and the pulmonary and
aortic valves snap shut
 3rd Heart Sound
• Produced during diastole
• Heard when the two inlet valves opens
• Not usually audible, may be heard in young child
 4th HeartSound
• Caused by contraction of both atria
• It’s heard when there is atrial hypertrophy
• Thickening of the wall of the atria

56. The Heart: Cardiac Conduction System
• Group of structures that send electrical impulses through
the heart
• Sinoatrial node (SA node)
• Wall of right atrium
• Generates impulse
• Natural pacemaker
• Sends impulse to AV node
• Atrioventricular node (AV node)
• Between atria just above ventricles
• Atria contract
• Sends impulse to the bundle of His
• Bundle of His
• Between ventricles
• Two branches
• Sends impulse to
Purkinje fibers
• Purkinje fibers
• Lateral walls of ventricles
• Ventricles contract

57. Cardiac Conduction System
The conduction system of the heart. The conduction system consists of specialized
myocardial cells that rapidly conduct the impulses from the atria into the ventricles.

58. Factors That Influence Blood Pressure
Five factors influence blood pressure:
• Cardiac output
• Peripheral vascular resistance
• Volume of circulating blood
• Viscosity of blood
• Elasticity of vessels walls
• Blood pressure increases with increased cardiac output,
peripheral vascular resistance, volume of blood,
viscosity of blood and rigidity of vessel walls.
• Blood pressure decreases with decreased cardiac
output, peripheral vascular resistance, volume of blood,
viscosity of blood and elasticity of vessel walls.

59. FACTORS AFFECTING BLOOD PRESSURE
Short term factors include –
Smoking – increases blood pressure, as the capillaries constrict or reduce in
size when the nicotine is present which increases the resistance to blood flew.
This effect lasts for about 20 minutes
Exercise – increases BP and HR (heart rate)
Fright, stress or anxiety – increases BP
Body position – affects BP due to the pull of gravity. Standing increases BP
while lying down decreases BP.
Long term factors include:
Diet – high intake of fat and salt can lead to a permanent increase in BP
into the unhealthy range. Fatty deposits narrow the artery
walls and lead to a loss of elasticity in artery walls
Stress – can cause high BP due to an imbalance in hormone levels
Exercise – regular exercise can lead to a decrease in blood pressure
when at rest, if blood pressure has been high

60. HEART DISORDERS
Abnormal heart rate: a regular heart rate lower than 60 and higher than 100 is
abnormal.
Heart block: SA node fails to send impulses which tell the heart to contract.
Ventricles contract at their own rate slower than the atria.
Arteriosclerosis: Hardening and narrowing of coronary arteries. If an artery blocks
then myocardial infarction occurs (heart attack)
Myocardial Infarction: blood flow is interrupted to heart muscle. This tissue dies.
Complete rest is needed. If a large area is starved of oxygen, death
will occur
Heart muscle can become infected
Valves of the heart can become ineffective
Cardiomyopathy – virus of the heart causing heart to enlarge and harden making it
ineffective. Death will result if the heart is not transplanted.