DETAILED CHAPTER OF BODY FLUIDS AND CIRCULATION. WELL EXPLAINED WITH DIAGRAM. WELL ORGANISED POWER[POINT TEMPLATES. SHORT AND PRECISE NOTES. WELL DEFINED TOPICS FOR EACH SUBJECTS.

1. BODY FLUIDS AND
CIRCULATION
SUBMITTED BY : D.C.DHARUN MUGHILAN
SUBMITTED TO :MRS. BHANUMATHI (PGT
BIOLOGY)

2. CIRCULATORY SYSTEM
This system is concerned with the circulation of body
fluids to distribute various substances to various body
parts. The circulatory system is also known as the
cardiovascular system.
It is an organ system that allows blood to circulate and
transport nutrients (such as electrolytes and amino
acids), oxygen, carbon dioxide, hormones, and blood
cells. These are circulated to and from cells in the
body to nourish it. The components of the human
circulatory system include the heart, blood, red and
white blood cells, platelets, and the lymphatic system.

3. CIRCULATORY SYSTEM

4. Functions of Circulatory System
 It transports nutrients from their sites of absorption to
different tissues and organs for storage, oxidation or synthesis
of tissue components.
It also carries waste products of metabolism from different
tissues to the organs meant for their excretion from the body.
It transports respiratory gases between the respiratory
organs and the tissues.
It carries metabolic intermediates from one tissue to another
for their further metabolism; for example, blood carries lactic
acid from muscles to the liver for its oxidation.
It also transports informational molecules such as hormones,
from their sites of origin to the tissue
 It uniformly distributes water, H+, chemical substances to all
over the body.

5. Types of Blood Circulation in Human
• The physiology of blood circulation was first described by Sir William Harvey
in 1628. The blood circulation in our body is divisible into 3 circuits –
• (i) Coronary circulation: It involves blood supply to the heart wall and also
drainage of the heart wall.
• (a) Coronary arteries: One pair, arising from the aortic arch just above the
semilunar valves. They break up into capillaries to supply oxygenated blood
to the heart wall.
• (b) Coronary veins: Numerous, collecting deoxygenated blood from the
heart wall and drains it into right auricle through coronary sinus which is
formed by joining of most of the coronary veins.
• (ii) Pulmonary circulation: It includes circulation between heart and lungs.
The right ventricle pumps deoxygenated blood into a single, thick vessel
called pulmonary aorta which ascends upward and outside heart gets
divided into longer, right and shorter, left pulmonary arteries running to the
respective lungs where oxygenation of blood takes place.
• (iii) Systemic circulation: In this, circulation of blood occurs between heart
and body organs. The left ventricle pumps the oxygenated blood into
systemic arch which supplies it to the body organs other than lungs through
a number of arteries.

6. BLOOD
Blood is a
connective
tissue which is
composed of a
fluid matrix
(plasma) and
formed
elements.

7. Plasma
• Plasma is a straw-coloured and viscous fluid.
• Plasma constitutes about 55% of the blood.
About 90% of plasma is water and about 6-8% is
composed of proteins.
• The major plasma proteins are; fibrinogen,
globulins and albumins.
• Fibrinogen play important role in blood
coagulation.
• Globulins are mainly involved in defense
mechanism and albumins help in osmotic
balance.
• Small amounts of minerals; like Na+, Ca+ +, Mg+
+, HCO3– and Cl–; are also present in plasma.
• Plasma also contains glucose, amino acids, lipids,
etc.
• Factors for clotting of blood are present in the
plasma in an inactive form. Plasma without the
clotting factors is called serum.

8. Formed Elements
• The formed elements constitute about
45% of the blood. Erythrocytes,
leucocytes and platelets are
collectively called formed elements.

9. Erythrocytes or Red Blood Cells
(RBCs)
• The RBCs are the most abundant cells in blood.
In a healthy adult, about 5 million to 5.5 million
RBCs are present per cubic mm of blood.
• RBCs are formed in the read bone marrow.
• In most of the mammals, nucleus is absent in the
RBCs. RBCs are biconcave in shape.
• The red colour is because of an iron containing
protein complex; called haemoglobin. In a
healthy adult, each 100ml of blood contains 12-
16 gm Hb.
• The average lifespan of RBCs is 120 days. RBCs
are finally destroyed in the spleen and hence,
spleen isthe graveyard of RBCs.
• RBCs play a significant role in transport of
respiratory gases.

10. Leucocytes or White Blood Cells
(WBCs):
• The WBCs are nucleated and are relatively lesser in number
than RBCs.
• In a healthy adult about 6000-8000 WBCs are present per
cubic mm of blood.
• Leucocytes are generally short lived.
• There are two main categories of WBCs:
Granulocytes , e.g., neutrophils, eosinophils and basophils
Agranulocytes. e.g., Lymphocytes and monocytes.
• Neutrophils: Neutrophils are the most abundant cells
among WBCs and comprise about 60-65%.
Monocytes: Monocytes comprise about 6-8% of WBCs.
Neutrophils and monocytes are phagocytic cells.
Basophils: Basophils secrete histamine, serotonin, heparin,
etc. They are involved in inflammatory reactions.
Eosinophils: Eosinophils comprise 2-3% of WBCs. These
resist infections and are also associated with allergic
reactions.
Lymphocytes: Lymphocytes comprise about 20-25% of
WBCs. There are two major types of lymphocytes, viz. B
and T types. Both the types are responsible for immune
responses of the body.

11. Platelets
• Platelets are also known as
thrombocytes.
• They are cell fragments produced
from megakaryocytes.
Megakaryocytes are special cells in
the bone marrow.
• Usually, one cubic mm of blood
contains 150,000-350,000 platelets.
• Platelets can release a variety of
substances. Most of these substances
are involved in blood coagulation.

13. BLOOD GROUPS
• Two such groupings – the ABO and Rh – are
widely used all over the world.
Importance of Blood Group: During blood
transfusion, the donor blood needs to be
carefully matched with the blood of a
recipient. Transfusion of unmatched blood
can lead to severe problems of clumping, i.e.
destruction of RBC.
The blood group O can be donated to
persons with any other blood group and
hence, an individual with O group is
called universal donor. A person with AB
blood group can accept blood from all blood
groups and hence, such an individual is
called universal recipient.

14. ABO Grouping
ABO grouping is based
on the presence or
absence of two surface
antigens on the RBCs,
viz. A and B.
Antigens are chemicals
which can induce
immune response. The
plasma also contains
two natural antibodies.
Antibodies are proteins
produced in response to
antigens.

15. Rh Grouping
The Rh antigen is similar to
one present in Rhesus
monkeys. It is also observed
on the surface of RBCs of
majority (nearly 80%)
humans. Such individuals are
called Rh positive (Rh +ve). A
person without Rh antigen is
called Rh negative (Rh –ve).
Significance of Rh
Group: An Rh -ve person, if
exposed to Rh +ve blood, will
form specific antibodies
against the Rh antigens.
Hence, Rh group should also
be matched before
transfusions.

16. Coagulation
of Blood
Blood coagulates in response to
an injury or trauma.
Coagulation is a mechanism to
prevent excessive loss of blood
in case of injury.
Clot is a dark reddish brown
scum which is formed at the
site of an injury over a period
of time.
This is formed by a network of
threads called fibrins in which
dead and damaged formed
elements of blood are trapped.

17. Process of Blood
Clotting
Inactive fibrinogen is present in
the plasma. It is converted by the
enzyme thrombin into active fibrin.
Thrombin is formed from the
inactive prothrombin.
An enzyme complex,
thrombokinase, is responsible for
this conversion.
This complex is formed by a series
of linked enzymatic reactions . The
process involves a number of
factors present in the plasma in an
inactive state.
An injury stimulates the platelets
to release certain factors which
activate the mechanism of
coagulation.

19. The Open and the Closed circulatory systems.
• Open circulatory system : In many advanced
invertebrates such as prawns, insects and
molluscs, the blood does not remain confined to
blood vessels but it flows freely through the body
cavity and channels called lacunae and sinuses in
the tissues. The body cavity is known as
hemocoele and the blood is hemolymph. In
insects, the tissues are in direct contact with the
blood. Hemolymph circulates in the whole body
due to the contractile activity of heart.

20. • Closed circulatory system : In closed circulatory system the
blood flows through proper blood vessels named arteries,
veins and blood capillaries. Arteries within the tissues divide
into arterioles, which then branch further to form
capillaries. Capillaries then unite to form venules, which
come out of the tissues and veins. Arteries have thick, elastic
and muscular walls which are made up of three concentric
layers viz., tunica externa, tunica media and tunica
interna. All these layers have got smooth or involuntary
muscles. Capillaries are extremely fine, thin blood vessels the
walls of which are made of a single layer of endothelial
cells. The muscles and elastic fibers are absent in
them. These capillaries are highly permeable to water and
small macromolecules. Various nutrients, respiratory gases,
metabolites and other substances are exchanged between
the blood and tissues through these capillaries.

21. DIFFERENCES BETWEEN OPEN AND CLOSED
CIRCULARY SYSTEMS
Open circulatory system
(1) In open circulatory system
blood flows through large
open spaces and channels
called lacunae and sinuses
among the tissues.
(2) Tissues are in direct contact
with the blood.
(3) Blood flow is very slow and
blood has very low pressure.
(4) Exchange of gases and
nutrients takes place directly
between blood and tissues
Closed circulatory system
(1) In closed circulatory system
blood flows through a closed
system of chambers called
heart and blood vessels.
(2) Blood does not come in direct
contact with tissue.
(3) Blood flow is quite rapid and
blood has a high pressure
(4) Nutrients and gases pass
through the capillary wall to
the tissue fluid from where
they are passed on to the
tissues.

22. Open circulatory system
(5) Less efficient as volume of
blood flowing through a
tissue cannot be controlled
as blood flows out in open
space.
(6) Open circulatory system is
found in higher invertebrates
like most arthropods such as
prawn, insects, etc., and in
some molluscs
(7) Respiratory pigment, if
present, is dissolved in
plasma; RBCs are not
present.
Closed circulatory system
(5) More efficient as volume of
blood can be regulated by the
contraction and relaxation of
the smooth muscles of the
blood vessels.
(6) closed circulatory system is
found in echinoderms, some
molluscs, annelids and all
vertebrates.
(7) Respiratory pigment is present
and may be dissolved in
plasma but is usually held in
RBCs.

23. ARTERIES AND VEINS
Structurally veins resemble arteries except that the three layers are very thin and
more elastic. In the veins the muscles and elastic connective tissues are poorly
developed. But the collagen fibers of the outer layer are very well developed. In
most of the veins the middle coat is extremely thin with practically no muscles. In
many veins semilunar valves are present in their lumen. These valves allow the
flow of the blood only in one direction i.e., towards the heart.

24. THE HEART
The heart is the central pumping organ of the
blood vascular system. It is a hollow
muscular structure and is made up of cardiac
muscles. It works throughout life rhythmically
without getting tired. It is enclosed in a double
membraneous sac called pericardium that is
filled with pericardial fluid. Mainly there are
two chambers in a heart – auricle or atrium
that receives the deoxygenated blood from
various parts of the body; and a ventricle that
distributes the oxygenated blood to the
body. The number of these chambers varies
in different animals.

25. PISCES
Branchial heart,Thick,
muscular, made of cardiac
muscles, has two chambers (i)
auricle and (ii) ventricle. The
heart is called venous heart
since it pumps deoxygenated
blood to gills for oxygenation.
This blood goes directly from
gills to visceral organs (single
circuit circulation). A sinus
venosus and conus arteriosus
is present. Lung fishes have 2
auricles and 1 ventricle.
For example : Labeo,
Scoliodon, Neoceratodus,etc.

26. AMPHIBIANS
Heart consists of
(a) Two auricles
(b) Undivided ventricle
(c) Sinus venosus
(d) Truncus arteriosus
(conus + proximal part of
aorta) Right auricle receives
blood from all the visceral
organs (deoxygenated) via
precaval and post caval.
Pulmonary artery carries
deoxygenated blood to lungs
for oxygenation. This blood
returns to left auricle via
pulmonary vein (Double
circuit circulation)
FOR EXAMPLE:Frog,Toad,etc.

27. REPTILES
Heart consists of :
(a) Left and right auricle
(b) Incompletely divided
ventricle
(Ventricle in crocodiles
gavialis and alligator is
completely divided)
(c) Sinus venosus
(d) Conus arteriosus
divided into right
systemic, left systemic and
pulmonary arch.
FOR EXAMPLE: Lizards
,Snakes , Turtles,etc.

28. AVES
Heart consists of
(a) Left and right auricle
(b) Left and right ventricle
(c) Complete separation
of arterial and venous
circulation
(d) Only right systemic
arch is present
(e) Sinus venosus and
truncus arterisious absent
FOR EXAMPLE:Pigeon,etc.

29. MAMMAL S
Heart consists of
(a) Left and right auricle
(b) Left and right ventricle
(c) Complete separation
of arterial and venous
circulation
(d)They have left systemic
arch.
(e) Sinus venosus and
truncus arterisious absent
FOR EXAMPLE:
Human,Rabbit,etc.

30. HUMAN HEART

31.  The mammalian heart including man is a hollow, cone-
shaped, muscular structure that lies in the thoracic cavity
above the diaphragm and in between the two lungs. It is
about the size of a fist measuring about 12 cm in length
and 9 cm in breadth. It weighs about 300 grams.
 It is a four chambered organ-two atria or auricles and two
ventricles. Deoxygenated blood is received into right
auricle by superior vena cava (from anterior region) and
inferior vena cava (from posterior region) of the
body. These vena cavae open directly into right auricle as
there is no sinus venosus.
 Right auricle also gets blood from coronary veins (from
the heart muscles itself). The right and left auricles are
separated by interauricular septum. Similarly, right and
left ventricles are also separated by interventricular
septum. Deoxygenated blood is then passed from the
right auricle to the right ventricle through the
atrioventricular aperture guarded by tricuspid valve
(having three flaps).

32.  The blood is then pumped into lungs for
oxygenation via pulmonary artery. After
oxygenation, the blood is brought back into left
auricle via four pulmonary veins. From left
auricle, blood (now oxygenated) goes to left
ventricle through atrio-ventricular aperture and
this opening is regulated by bicuspid (having two
flaps) or mitral valve.
 The left ventricle has also got chordae tendinae
and papillary muscles which prevent the valves
(both bicuspid and tricuspid) from being pushed
into auricles at the time of ventricular
contraction. Thus the walls of left ventricle are
thicker than the walls of right ventricle.
 The oxygenated blood from left ventricle is then
distributed to all parts of the body with the help
of aorta. The openings of the aorta and other
major arteries are guarded by semilunar valves
that prevent the back flow of blood.

33. Differences between first and seconds heart sounds
First heart sound
(Lubb)
Second heart
sound (Dup)
(1) It is produced by
closure of bicuspid and
tricuspid valves at the
start of ventricular
systole.
(1) It is produced by
closure of semilunar
valves at the start of
ventricular diastole.
(2) It is low pitched, less
loud and of long
duration.
(2) It is higher pitched,
louder, sharper and of
short duration.
(3) It lasts for 0.15 (3) It lasts for 0.1

34. CIRCULATION OF BLOOD THROUGH HEART
(1) The heart pumps blood to all parts of the
body.
(2) The deoxygenated blood is drained into right
auricle through superior and inferior vena cava
and coronary sinus whereas the pulmonary
veins carry oxygenated blood from lungs to the
left auricle. This is called as Auricular circulation.
(3) About 70% of the auricular blood passes into
the ventricles during diastole. This phase is
called diastasis.
(4) The rest of 30% of blood passes into the
ventricles due to auricular systole (contraction).
(5) In this way, blood reaches the ventricles and is
called ventricular filling.
(6) During ventricular systole (which starts first in
left ventricle than in right ventricle), the
pressure increases in the ventricles, thus, forcing
the oxygenated blood from left ventricle into
systemic aorta and deoxygenated blood from
right ventricle into pulmonary aorta.
(7) The systemic arch
distributes the oxygenated
blood to all the body parts
except lungs while pulmonary
aorta carries the
deoxygenated blood to lungs
for oxygenation.

35. HEART RATE AND PULSE
• In the resting condition, human heart beats at the rate of about 70
times per minute. But, the heart beat rate increases during exercise,
fever, and emotions like anger and fear.
• During each heart beat, the blood is pumped from the ventricles of
the heart into the aorta to be distributed to all parts of the body. This
happens during the ventricular systole and is repeated every 0.8
seconds. The blood from aorta then goes to other arteries of the
parts. This causes a rhythmic contraction in the aorta and its main
arteries. It can be felt as regular jerks or pulse in the regions where
arteries are present superficially like wrist , neck and temples. This is
known as arterial pulse.
• The pulse rate is, therefore, same as that of heart beat rate. This
heart beat rate differs from species to species. In general, the smaller
the animal, the greater the heart beat. Hence, larger animals have
lower heart rates. For example, an elephant has a normal heart beat
rate of about 25 times per minute, where as mouse has a normal
heart beat rate of several hundreds per minutes.

36. Automatic rhythmicity of the heart:
• The mammalian heart is a myogenic heart i.e., the heart beat originate from a
muscle (but it is regulated by nerves). In the right atrium near the region
where superior vena cava opens, a specialised muscle called sinu-auricular
node (SA-node) is present from where the heart beat originates. It is also
called as pace maker and is richly supplied with blood capillaries. A wave of
contraction (systole) originates from it and spreads over to the whole heart.
• At the junction of right atrium and right ventricle, a tissue called auriculo-
ventricular node (AV-node) is present that picks up the wave of contraction
propagated by SA-node. This is also known as bundle of His. Branches of this
spread over the ventricle forming the Purkinje system. The wave of contraction
spreads over the ventricle through AV-node and its Purkinje system.
• The heart is supplied with vagus (parasympathetic) and sympathetic nerve
fibers. The vagus nerve is inhibitory and so when stimulated slows down the
heart beat; while the sympathetic nerve is acceleratory and so when stimulated
fastens the heart beat. This happens because these nerves release chemicals
(hormones) when stimulated.

38. Fractions of cardiac output :
• Amount of pure blood going to an organ per minute
is called as fraction of the organ.
(i) Cardiac fraction – 200 ml/min.
(ii) Hepatic fraction – 1500 ml/min. (28% of blood as
liver is the busiest organ of body and has maximum
power of regeneration).
(iii) Renal fraction – 1300 ml/min (25% of blood)
(iv) Myofraction – 600-900 ml/min.
(v) Cephalic organs – 700-800 ml/min.

39. Arterial Blood Pressure:
The pumping action of the heart maintains a
pressure of blood in the arteries. This is called
Arterial blood pressure. It helps to pump blood at a
high velocity along the arteries in the closed
circulatory system. The blood pressure is far lower in
the open circulatory system.

40. Blood Flow in Veins:
The blood pressure is low in veins, because the blood flows
through narrow arterioles and capillaries to enter wider
veins. At many places in the body, this blood pressure is not
sufficient to drive the blood through the veins back to the
heart. Veins have thinner walls than arteries and are more
easily compressed. There are also many valves inside the
veins. These valves permit the flow of blood in the veins
towards the heart and prevent blood flow in the reverse
direction. Contraction of muscles and changes of body
posture compresses the veins to move the blood inside
them. During this both cases, blood moves towards the heart
only, because the venous valves prevent the blood flow in the
opposite direction. This is a major process for venous blood
flow.

41. Electrocardiogram
(ECG)
(i) Depolarisation waves: They represent
the generation of the potential
difference. These waves appear only
when both electrodes of galvanometer
are in different fields. When both the
electrodes are in same field, there are no
deflection and wave drops down to base
line.
(ii) Repolarisation waves: They appear
when depolarisation is over and the
muscle fibre is returning to its original
polarity. When both electrodes are in
same polarity (means 100% repolarisation
and 100% depolarisation), there is no
deflection.
(a) P wave: Indicates impulse of
contraction generated by S.A. node and
its spread in atria causing atrial
depolarisation. The interval PQ represents
atrial contraction and takes 0.1 second.
b) QRS complex: Indicates spread of impulse of
contraction from A.V node to the wall of ventricles
through bundle of His and pukinje fibres causing
ventricular depolarisation. This complex also represents
repolarization of S.A. node.
The RS of QRS wave and ST interval show ventricular
contraction (0.3 seconds). QRS is related to ventricular
systole.
(c)T wave: Indicates repolarisation during ventricular
relaxation.

42. Lymph and Tissue Fluid
• It occurs in the spaces in between the cells of a tissue and is called as interstitial
fluid or tissue fluid.
• The exchange of any material (solid, liquid or a gas) that occurs between the blood
and the tissue cells always takes place through this fluid. Under the pressure of
blood in the capillaries some of the water and desired solutes are filtered out from
the blood plasma into the tissue spaces to form the tissue fluid.
• The composition of this tissue fluid is very similar to that of plasma except that it
has much less protein. Proteins are less because some of the proteins are not
filtered out from the capillary walls (impermeable).
• Some of the tissue fluid enters tiny channels called lymph vessels and the fluid
collected in them is called lymph and this system is known as lymphatic
system. These lymph vessels unite to form larger lymph vessels which ultimately
drain into two large lymph vessels called thoracic duct and the right lymphatic
duct. These open into veins returning the lymph finally into venous blood and so in
the general circulatory system. This movement of lymph is mainly due to the
squeezing action of the surrounding muscles. So the lymphatic system is slow and
uncertain. Exercise increases the rate of lymph circulation.
Generally, the rate of lymph formation is equal to the rate of its return to the blood
stream. But sometimes, the formation rate of lymph exceeds the rate of its return
to blood. The increased volume of fluid around the cells then creates a swelling,
called dropsy or oedema.

43. Functions of Lymph
•
1. It serves to return interstitial fluid into blood.
2. The plasma proteins macromolecules
synthesized by the liver cells, cannot pass into the
blood vessels, but can diffuse into the lymph vessels
through their wall and they come to the blood
through lymph.
3. It also carries absorbed fats and lipids from the
small intestine to the blood in the form of
chylomicron droplet

44. Lymphatic System
• The lymphatic system is an extension of the circulatory system. It
consists of a fluid known as lymph, lymph capillaries and lymph
ducts.
(a) Lymph: It can be defined as blood minus RBC's. In addition to the
blood vascular system all vertebrate possess a lymphatic system.
It is colourless or yellowish fluid present in the lymph vessels. It is
a mobile connective tissue like blood and is formed by the
filtration of blood.
(b) Lymph capillaries: Small, thin, lined by endothelium resting on a
basement membrane and fine whose one end is blind and other
end unites to form lymphatic ducts.
(c) Lymphatic ducts or vessels: Numerous, present in various parts
of body. These vessels are like veins as they have all the three
layers – tunica externa, tunica media and tunica interna, and are
provided with watch pocket or semilunar valves but valves are
more in number than veins.

45. Differences between blood and lymph
S.No.
Characters Blood Lymph
(1) RBC Present Absent
(2) Blood platelets Present Absent
(3) WBC Present, generally
7000/cu mm
Present, generally
500-75000/cu mm
(4) Plasma Present Present
(5) Albumin : globulin Albumin > Globulin Albumin > Globulin
(6) Fibrinogen More Less
(7) Coagulation
property
More Less
(8) Direction of flow Two way, heart to
tissues and tissues
to heart
One way, tissues to
heart
(9) Rate of flow Fast Slow
(10) Glucose, urea and CO2 Less More

46. Disorders of Circulatory System:
1. High Blood Pressure (Hypertension): It is the term for blood
pressurethat is higher than normal of 120/80. In the instrument 120
is Systolic / pumping pressure, 80 is Diastolic, resting pressure. If
repeated check which shows 140/90 and higher shows Hypertension.
It may leads to heart diseases and also affect vital organs like brain
and kidney.
2.Coronary Artery Disease (CAD) : it is also known as Atherosclerosis,
due to damage in the blood vessels of heart tissues. Basically it it due
to, deposition excess of Calcium, fat, cholesterol and fibrous tissues
which makes the lumen of arteries narrower.
3.Angina: It is also known as “angina pectoris”, it is symptom of acute
chest pain due to less oxygen supply to heart.
4.Heart Failure: It is the state when heart is not pumping blood
effectively to other organs of the body.
•