EVOLUTION AND HEART AND AORTIC ARCHES

1. PAPER-I
[CHORDATE]
PRESENTATION

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 NAME: ANSARI KAUSAR MOHD
KHALID
 ID NO: 7763
 CLASS: MSc-I
 PAPER-1 [CHORDATE]
DEPARTMENT OF ZOOLOGY

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TOPIC:
CIRCULATION : HEART AND AORTIC
ARCHES

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PAGE
03  CIRCULATION:
Circulatory system refers to the heart and a
network of blood vessels that move blood,
nutrients and oxygen throughout the body. The
circulatory system consists of the heart,
capillaries, arteries and veins. While arteries carry
blood away from the heart, the veins carry blood
back to the heart.

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 TYPES OF CIRCULATION:
OPEN CIRCULATORY SYSTEM: In an open
circulatory system, blood vessels transport all
fluids into a cavity. When the animal moves, the
blood inside the cavity moves freely around the
body in all directions. The blood bathes the organs
directly, thus supplying oxygen and removing
waste from the organs. Most invertebrates
(crabs, insects, snails etc.) have an open
circulatory system.
CLOSED CIRCULATORY SYSTEMS
Closed circulatory systems are different to open
circulatory systems because blood never leaves
the blood vessels. Instead, it is transferred from
one blood vessel to another continuously without
entering a cavity. Blood is transported in a single
direction, delivering oxygen and nutrients to cells
and removing waste products.
OPEN CIRCULATORY
SYSTEM:
CLOSED CIRCULATORY SYSTEMS

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PAGE
07  HEART:
- A Muscular pump (Cardiac Muscle)
- Contain a pacemaker to regulate rate but
rate can also be influenced by the
AUTONOMIC NERVOUS SYSTEM.

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 SINGLE CHAMBERED HEART:
In Amphioxus (primitive chordate), a true heart
is not found. A part of ventral aorta beneath the
pharynx is muscular and contractile and acts as
heart.
 PRIMITIVE
CHORDATE

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 TWO CHAMBERED HEART:
• Except Dipnoi, the circulatory system in fishes
from teleosts to cartilaginous fishes, only
unoxygenated blood goes to the heart, from
there it is pumped to the gills, aerated and
then distributed to the body.
• They are sinus venosus and atrium for
receiving venous blood, and a ventricle and
conus arteriosus for pumping this blood.
• The heart is enclosed within pericardial cavity
separated from body cavity by a transverse
septum.
• The heart is, thus, 2-chambered with a single
circulation of blood.
 PIECES [FISH]
HEART

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 THREE CHAMBERED HEART:
• In diphoans a septum divides the atrium into
a right and left chamber.
• This is correlated with the use of the swim-
bladder as an organ of respiration and
represents the first step toward the
development of the double-type circulatory
system whereby both oxygenated and
unoxygenated blood enter the heart and are
kept separate.
• Generally, in amphibians with functional lungs,
the heart includes a sinus venosus, right and
left atria divided by an anatomically complete
interatrial septum, a trabeculate ventricle
lacking any internal subdivision
 AMPHIBIANS
HEART

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 THREE CHAMBERED HEART:
• In reptiles, the heart is further advanced.
The atrium is always completely separated
into a right and left chamber.
• The ventricle is also partly divided by a
septum in most reptiles, and in the alligators
and crocodiles is completely two-chambered.
• This means that oxygenated blood coming from
the lungs to the left side of the heart is
essentially separated from the non-oxygenated
blood from the body to the right side.
• Thus, in crocodilians, the two types of blood is
completely separated, and nearly complete in
other reptiles, but some mixing does occur in
other parts of the circulatory system.
 REPTILIANS
HEART

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 FOUR CHAMBERED HEART:
• In birds and Mammals, the ventricle is
completely divided into two, so that the heart
is four chambered (2 auricles and 2
ventricles).
• There is complete separation of venous and
arterial blood.
• The systemic aorta leaves the left ventricle
and carries blood to the head and body.
• While the pulmonary artery leaves the right
ventricle and carries blood to the lungs for
oxygenation.
 AVIANS
HEART

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 FOUR CHAMBERED HEART:
• Thus, there is double circulation in which there
is no mixing of blood at any place.
• The sinus venosus is completely incorporated
into right auricle, which receives two precaval
and a postcaval.
• The left auricle receives oxygenated blood
through pulmonary veins.
• the pulmonary aorta arises from the right
ventricle, and single systemic aorta arises from
the left ventricle, and both have valves at
their bases.
 MAMMAL
HEART

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AORTIC
ARCHES

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REFERENCE:
https://www.zoologytalks.com/aortic-
arches-in-vertebrates/
https://www.slideshare.net/reddysir/aor
tic-arches-240175225
https://www.notesonzoology.com/verteb
rates/circulatory-system-in-
vertebrates-with-diagram-chordata-
zoology/9063

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-THANK-
YOU