BIOLOGY
TRANSPORT IN MAM-
MALS
The circulatory system in man un-
dergoes an open system which is
the flow of blood in blood vessels.
The circulatory system comprises of the fol-
lowing:
1) Blood
2) Blood vessels
3) Heart
1) Blood has 4 components - plasma which is 90% of water , blood platelets
which are fragments of cytoplasm which help in clotting of the blood along
with vitamin K and are produced by bone marrow , red blood cells (RBC)
which are circular , biconcave disc shaped cells which are present in abun-
dance in our body. They contain no organelles but only a red pigment known
as haemoglobin which is an iron made compound. 1 haemoglobin binds to 4
oxygen to form oxyhaemoglobin ( blood which is bright red in colour) , and
white blood cells (WBC) which are colourless irregular shaped cells which
have a nucleus. They can squeeze in any tissue in the body at the site of infec-
tion as they help in fighting them. They are present in a very small amount in
our body. There are two types of white blood cells-
1- Lymphocytes: that are produced by lymph nodes and their nucleus is
nearly round.
2- Phagocytes: that are produced by bone marrow and are used to engulf
pathogens that enter our body.
As we now look upon the functions of blood , we may divide them into 2
parts:
, ~Protective Functions
~Transport Functions
The protective functions include the process of phagocytosis which is basi-
cally when a pathogen enters the body, the body produces antibodies which
mark the pathogen and form a ball like structure - agglutination which is then
engulfed by the phagocytes.
The other protective function of the blood is its clotting. When a tissue is
damaged , it produces an enzyme called thrombokinase which produces inac-
tive enzyme prothrombin which converts into active form called thrombin.
That active enzyme converts soluble fibrin protein into insoluble fibrin
threads. Then they form a meshwark that entangles blood cells and platelets
to form a clot and seal the wound.
2) Now we reach upon the concept of blood vessels which are basically the
passage through the blood flows around our whole body. There are 3 blood
vessels- capillaries, arteries and veins.
~Capillaries are easy to identify. They are microscopic blood vessels that are
made up of only a single layer of flattened cells called endothelium. They have
a diameter of one cell- which means only 1 cell can pass at one time.
~Arteries are the blood vessels that
carry blood away from the heart.
They carry oxygenated blood
throughout the body and have thick
elastic walls to withstand the high
blood pressure as they carry blood
from the heart. The elastic fibres al-
TRANSPORT IN MAM-
MALS
The circulatory system in man un-
dergoes an open system which is
the flow of blood in blood vessels.
The circulatory system comprises of the fol-
lowing:
1) Blood
2) Blood vessels
3) Heart
1) Blood has 4 components - plasma which is 90% of water , blood platelets
which are fragments of cytoplasm which help in clotting of the blood along
with vitamin K and are produced by bone marrow , red blood cells (RBC)
which are circular , biconcave disc shaped cells which are present in abun-
dance in our body. They contain no organelles but only a red pigment known
as haemoglobin which is an iron made compound. 1 haemoglobin binds to 4
oxygen to form oxyhaemoglobin ( blood which is bright red in colour) , and
white blood cells (WBC) which are colourless irregular shaped cells which
have a nucleus. They can squeeze in any tissue in the body at the site of infec-
tion as they help in fighting them. They are present in a very small amount in
our body. There are two types of white blood cells-
1- Lymphocytes: that are produced by lymph nodes and their nucleus is
nearly round.
2- Phagocytes: that are produced by bone marrow and are used to engulf
pathogens that enter our body.
As we now look upon the functions of blood , we may divide them into 2
parts:
, ~Protective Functions
~Transport Functions
The protective functions include the process of phagocytosis which is basi-
cally when a pathogen enters the body, the body produces antibodies which
mark the pathogen and form a ball like structure - agglutination which is then
engulfed by the phagocytes.
The other protective function of the blood is its clotting. When a tissue is
damaged , it produces an enzyme called thrombokinase which produces inac-
tive enzyme prothrombin which converts into active form called thrombin.
That active enzyme converts soluble fibrin protein into insoluble fibrin
threads. Then they form a meshwark that entangles blood cells and platelets
to form a clot and seal the wound.
2) Now we reach upon the concept of blood vessels which are basically the
passage through the blood flows around our whole body. There are 3 blood
vessels- capillaries, arteries and veins.
~Capillaries are easy to identify. They are microscopic blood vessels that are
made up of only a single layer of flattened cells called endothelium. They have
a diameter of one cell- which means only 1 cell can pass at one time.
~Arteries are the blood vessels that
carry blood away from the heart.
They carry oxygenated blood
throughout the body and have thick
elastic walls to withstand the high
blood pressure as they carry blood
from the heart. The elastic fibres al-
