It's about body fluids and deals with process of circulation.It builds your mind to know the functions of heart.

1. Key Takeaways
• Human circulatory system
→Open and closed circulatorysystem
→Circulating fluid
→Heart
→Blood vessels
→Types of blood circulation
NOT
B I O L O G Y
BODY FLUIDSAND
CIRCULATION
CIRCULA
TORY SYSTEM
Lungs
(Respiratory
system)
Body
O2
CO 2
Circulatory System
• It is also known as the cardiovascularsystem.
• Its primary role is to provide nutrients, gases,and hormones to different parts of thebody.
• It also transports O2 and CO2 in the respiratorysystem.
• It collects all the metabolic waste from different parts of the body and delivers it to the
excretory system.
Intestine
(Digestive system)
Nutrients and water
Wastelike urea
Kidneys
(Excretory system)
• Different animals have different types of circulatorysystems.
swastik

2. Open Closed
• Example:All arthropods, molluscs
• The blood pumped by the heart is always circulated
through aclosed network of blood vessels.
• The flow of fluid through this systemcan be regulated.
T
ypes of circulatorysystems seen in animals
02
Heart
Valve
• The heart pumps the circulatoryfluid known as
hemolymph into open spaces or body cavities.
• The hemolymph returns to theheart via small pores
known asostia.
Ostia
Heart
Body
cells Body
cells
• Example:Annelids, chordates
Blood
vessels
Heart
Heart
Heart Heart
Heart
Ostia
Blood
Annelids
Arthropods
Molluscs Chordates
Blood
vessels
Blood vessels
Blood
vessels
Heart
Hemolymph in sinuses
surrounding organs
swastik

3. 03
Human CirculatorySystem
Circulating fluid
Heart
Blood vessels
Blood Lymph
• It is a fluid connective tissue.
• It transports oxygen, nutrients, antibodies,
etc.
• It is a colourless fluid.
• It carries immune cells, nutrients, etc.
Human heart
• It is a muscularorgan.
• It is derived from mesodermalcells.
• It is located between the lungs in the thoracic cavity, slightly towards the left of thesternum
(breastbone).
• It is roughly the size of a clenched fist and 12cmlong.
Size
12cm
Human heart
Circulating fluids

4. 04
• It has three layers.
Layers in the heart
Pericardium
Pericardium
Myocardium
Pericardial
Fluid
Pericardium
(Around heart)
It is a protective covering
around the heart,and the space between
pericardium and myocardium is filled with
pericardialfluid.
Myocardium
(Muscle heart)
It is a muscular wall of heart.
It contracts to pump blood out of the heart
andthen
relaxes as the heartrefills with returning
blood. Endocardium
(Inner heart)
Pericardium
Myocardium
Endocardium
It remains in contact with blood.
Structure of a human heart
• Human heart consists of four chambers:
→Right and left atria.
→Right and left ventricles.
• Atria
→These are the small upper chambers.
Debananda Sahoo, VGYAN CLASSES

5. 05
→The walls of atria are thin.
→The atria are named based on their position
→Larger right atrium and the left atrium.
→They are separated by a thin muscular interatrialseptum.
• Ventricles
→These are the large lower chambers.
→They are separated from atria by thick fibrous tissue called atrioventricularseptum.
→The ventricles are named based on their position
→The right ventricles and the left ventricle.
→The left and right ventricles are separated by the thick muscular tissuecalled interventricular septum
Superior vena cava
Carries oxygen poor- blood from the
upper
parts of the body
Pulmonaryveins
Blood enters the left atrium
through the four pulmonary
vein openings.
Right atrium
Receives blood from the
body through vena cava
Aorta
Pumps blood to the rest of the body
Pulmonaryartery
Pumps blood to thelungs
Pulmonarysemilunar valve
Guards the opening of the right ventricle to
the pulmonaryartery
Aortic semilunarvalve Guards the
opening ofthe left ventricle to the
aorta
Left atrium
Receives oxygenated blood
from the lungs
Inferior vena cava Carries
oxygen-poor blood from the
lower parts of the body
Right ventricle
Receives blood from the right atrium and then
pumps blood into the pulmonary artery or
pulmonary trunk
Left ventricle Receives blood
from the left atrium and thenpumps
blood into the aorta which then
supplies to the whole body
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6. 06
• Comparison of left and right ventricles
Left ventricle
The left ventricle is larger and three
times thicker than the right ventricle.
→As the left ventriclehas to pump
blood to the
whole body throughaorta.
Right ventricle
Ventricles
Rightventricle Left ventricle
Comprises of thinwall Comprises of thick wall
Receives deoxygenated blood fromthe right atrium Receives oxygenated blood from the left atrium
Pumps blood to lungs through the pulmonarytrunk Pumps blood to the whole bodythrough the aorta
• Septum
→The septum’s primary function in the heart is to isolate the two sidesof the heart.
Atria
Interatrial septum
Separates left and right
atrium
Interventricular
septum
Separates left and right
ventricles
Atrioventricular septum
Atria and ventricles on the
same sideare separated by
atrioventricular septum.
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7. 07
• External structure of the heart
• Valve
→Valves are flaps of fibrous tissues located in the cardiac chambers.
→They ensure that blood flows in a single direction(unidirectional).
→Flaps also prevent blood from flowing backwards.
Tricuspid valve
Bicuspid or mitral valve
• It has three muscular flaps.
• It guards the opening between
right atrium and right ventricle.
• It has two flaps.
• It guards the passage from left
atrium to left ventricle.
Chordae tendinae
Papillarymuscles
They anchor the bicuspid and tricuspid valves
to theventricular papillary muscles and keep
the valves in closed position during
ventricular systole.
Grooves (Sulci) Different
divisions in the heart create
depressions known as grooves.
Atrioventricular sulcus
The thick atrioventricular
septum formsgroove on the
surface of heart and runs
between the atria and
ventricles and the surface of
the heart.
Interatrial groove The
thick interatrial septum
formsgroove on the surface
of the heart.
Anterior view
Posteriorview
Interventricular
sulcus
The thick interventricular septum formsgroove on the surface of
the heart and runs between the two ventricles and the surface of
theheart.
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8. 08
Blood vessels
• Bluish or deep red in colour as theycarry
deoxygenated blood.
Arteries
• Pinkish or bright red in colour as theycarry
oxygenated blood
• Blood flows with a high pressure andspeed.
Veins
Capillaries
• Arteries branch out into arteriolesand veins into venules.
• These arterioles and venules branch out into smaller, thinner
blood vessels known as capillaries.
• Allow exchange of gases and other materials with the
cells of theorgans.
• They act as a connection between arteries and veins.
Layers of arteries and veins
Heart
Heart
Arteries
Carry blood
Veins Carry
blood
Different parts of body
Different parts of
body
Tunicaintima
Tunicamedia
Tunicaexterna
Squamous
endoithelium
Smooth muscle and elastic
fibres
Fibrous connective tissue
with collagen fibres
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9. 09
The total length of blood vessels in an average human adult is twice of Earth’s circumference at the equator!
Did you know?
T
ypes of blood circulation
Single circulation
• Seen in 2-chambered heart
• Contains one atrium and one ventricle
• Example: Fish
• The deoxygenated blood is pumped from ventricles to gills.
Incomplete double circulation
• Seen in 3-chambered heart
• Contains two atria and one ventricle
• Examples: Reptiles and amphibians except crocodile
• The left atrium receives oxygenated blood from gills/skin/lungs and the right atrium receives
deoxygenated blood from thebody.
• They inter-mix in a single ventricle, which pumps it out to gills/skin/ lungs and to different parts of
body, thus it is known as incomplete circulation.
• Blood passes through the heart twice, hence known as double circulation.
• It is very inefficient.
Complete double circulation
• Seen in 4-chambered heart
• Contains two atria and two ventricles
• Examples: Birds and mammals
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10. 10
SummarySheet
Open Closed
• The heart pumps the circulatoryfluid known as
hemolymph into open spaces or body cavities.
• The hemolymph returns to theheart via small pores
known asostia.
• The blood pumped by the heart is always circulated
through aclosed network of blood vessels.
• The flow of fluid through this systemcan be regulated.
Types of circulatorysystems seen in animals
Arteries Veins
Involved in carrying oxygenated blood Involved in carrying deoxygenated blood
Carry blood away from the heart tovarious parts of the body Carry blood towards the heart fromvarious parts of the body
Valves are absent Valves are present
Gills Lungs
Various
body
Right
atrium
Ventricle Right
ventricle
Various
body parts
Left
ventricle
Right
atrium
Left
atrium
Left
atrium
Incomplete double
circulation
Complete double
circulation
Heart
Single circulation parts
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11. 1
1
Human CirculatorySystem
Circulating fluid
Heart
Myocardium
(Muscle heart)
Blood vessels
Blood
Veins
Transports nutrients, oxygen, antibodies, etc.
Endocardium
(Inner heart)
Arteries
Carry blood from the heart to differentparts of the body
Carry blood from different body parts tothe heart
Capillaries
Connecting link between arteries andveins
Lymph
Carries immune cells, nutrients, etc.
Pericardium
(Around heart)
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12. Atrium Ventricle
Thin-walled Thick-walled
Forms the upper chamber of theheart Forms the lower chamber of theheart
Divided into right and leftatria Divided into left and right ventricles
Collects blood from the body andsupplies to ventricles Supplies blood to different parts ofthe body
12
Single circulation Incomplete double
circulation
Complete double
circulation
• Seen in 2-chambered heart
• Contains one atrium and one
ventricle
• Example: Fish
• 3-chambered heart
• Contains two atriaand
one ventricle
• Examples: Reptilesand
amphibians except crocodile
• Blood passesthrough the heart
twice
• Mixing of bloodoccurs
• Inefficient
• 4-chambered heart
• Contains two atriaand two
ventricles
• Examples: Birds and mammals
• No mixing of blood
• Two separate circulatory
pathways are present
T
ypes of blood circulation
Debananda Sahoo, VGYAN CLASSES