Blood
The role of blood
Distribution - transporting things around the body
Nutrients: blood carries oxygen form your lungs, nutrients
from food
Waste: removes carbon dioxide, takes it to the lungs to get rid
of it
Hormones: these chemical messengers help different parts of
the body communicate
Protection - defending the body
Infection: blood has white blood cells that fight germs
Blood loss: blood has platelets and clotting proteins that help
stop bleeding once a cut happens
Regulation - keeping things balanced
Body temperature: blood keeps the body temperature stable
by spreading heat around the body
pH: blood keeps the pH level (acidity) in your body balanced
so cells can work properly
Fluid volume: blood helps maintain the right amount of fluid in
the body, so organs work well and blood pressure stays
normal
What's in blood?
55% plasma (electrolytes, plasma proteins, metabolic by
products, nutrients, respiratory gases, hormones)
1% buffy coat (white blood cells, platelets)
45% red blood cells
,Red blood cells - oxygen transport
Role of red blood cells is to carry oxygen from the lungs to the
rest of the body
Haemoglobin: inside red blood cells, its what carries the
oxygen
- each haemoglobin has 4 heme groups
- each heme group can carry 1 oxygen molecule
- so 1 haemoglobin can carry 4 oxygen molecules in total
98% of the oxygen in the blood is carried by haemoglobin,
where 2% dissolves in blood plasma
How it works:
Oxygen binds to the iron in the heme groups
This bond is loose and reversible. In the lungs, where oxygen
is high, haemoglobin has a high affinity (attraction) for
oxygen, it picks it up
In body tissues (muscles), where oxygen is needed,
haemoglobin's affinity is low, it lets go of the oxygen
Red blood cells - carbon dioxide transport
Red blood cells help transport carbon dioxide from the body
back to the lungs
Blood carries co2 to your lungs to breathe it out, it travels in
three main ways
Main 1: 7% of co2 dissolves directly in the liquid part of the
blood, blood plasma
Main 2: 23% of co2 enters red blood cells and binds to
haemoglobin, it binds to a different part of the haemoglobin
than oxygen does
, Main 3: 70% of co2 takes this route. Inside the red blood cells,
an enzyme called carbonic anhydrase helps convert co2 into
carbonic acid. This splits into hydrogen and bicarbonate ion.
The bicarbonate goes into the plasma and is transported that
way. Later in the lungs, this process is reversed, and co2 is
released to be exhaled.
Platelets - cells that stop bleeding by forming clots
Uselessly float around the blood. The inner lining of blood
vessels (endothelium) keeps them inactive and moving until
its needed
When a blood vessel is damaged, the endothelial cells are
broken. Platelets are attracted to the damaged area
They stick together at the injury site, and work with a plasma
protein called fibrinogen, this helps form fibrin threads that
hold the clot together like a net
4 main steps of blood clotting
Vascular spasm: blood vessels near the injury contract. This
helps reduce blood flow and limit bleeding right away
Platelet plug: damaged endothelial cells release signals that
attract platelets. They stick to the site/each other, forming a
temporary plug
Coagulation: a protein in the blood, fibrinogen, gets turned
into fibrin. Fibrin forms sticky fibres that create strong mesh
over the platelet plug. This solid clot traps red blood cells and
seals the wound
Fibrinolysis: once the injury heals, the clot is no longer
needed. An enzyme plasmin breaks down the fibrin fibres, this
clears the clot and restores normal blood flow
The lymphatic system
Immunity: defends the body against infection
Lymphatic drainage: removes excess fluid from tissues and
returns it to the blood
The role of blood
Distribution - transporting things around the body
Nutrients: blood carries oxygen form your lungs, nutrients
from food
Waste: removes carbon dioxide, takes it to the lungs to get rid
of it
Hormones: these chemical messengers help different parts of
the body communicate
Protection - defending the body
Infection: blood has white blood cells that fight germs
Blood loss: blood has platelets and clotting proteins that help
stop bleeding once a cut happens
Regulation - keeping things balanced
Body temperature: blood keeps the body temperature stable
by spreading heat around the body
pH: blood keeps the pH level (acidity) in your body balanced
so cells can work properly
Fluid volume: blood helps maintain the right amount of fluid in
the body, so organs work well and blood pressure stays
normal
What's in blood?
55% plasma (electrolytes, plasma proteins, metabolic by
products, nutrients, respiratory gases, hormones)
1% buffy coat (white blood cells, platelets)
45% red blood cells
,Red blood cells - oxygen transport
Role of red blood cells is to carry oxygen from the lungs to the
rest of the body
Haemoglobin: inside red blood cells, its what carries the
oxygen
- each haemoglobin has 4 heme groups
- each heme group can carry 1 oxygen molecule
- so 1 haemoglobin can carry 4 oxygen molecules in total
98% of the oxygen in the blood is carried by haemoglobin,
where 2% dissolves in blood plasma
How it works:
Oxygen binds to the iron in the heme groups
This bond is loose and reversible. In the lungs, where oxygen
is high, haemoglobin has a high affinity (attraction) for
oxygen, it picks it up
In body tissues (muscles), where oxygen is needed,
haemoglobin's affinity is low, it lets go of the oxygen
Red blood cells - carbon dioxide transport
Red blood cells help transport carbon dioxide from the body
back to the lungs
Blood carries co2 to your lungs to breathe it out, it travels in
three main ways
Main 1: 7% of co2 dissolves directly in the liquid part of the
blood, blood plasma
Main 2: 23% of co2 enters red blood cells and binds to
haemoglobin, it binds to a different part of the haemoglobin
than oxygen does
, Main 3: 70% of co2 takes this route. Inside the red blood cells,
an enzyme called carbonic anhydrase helps convert co2 into
carbonic acid. This splits into hydrogen and bicarbonate ion.
The bicarbonate goes into the plasma and is transported that
way. Later in the lungs, this process is reversed, and co2 is
released to be exhaled.
Platelets - cells that stop bleeding by forming clots
Uselessly float around the blood. The inner lining of blood
vessels (endothelium) keeps them inactive and moving until
its needed
When a blood vessel is damaged, the endothelial cells are
broken. Platelets are attracted to the damaged area
They stick together at the injury site, and work with a plasma
protein called fibrinogen, this helps form fibrin threads that
hold the clot together like a net
4 main steps of blood clotting
Vascular spasm: blood vessels near the injury contract. This
helps reduce blood flow and limit bleeding right away
Platelet plug: damaged endothelial cells release signals that
attract platelets. They stick to the site/each other, forming a
temporary plug
Coagulation: a protein in the blood, fibrinogen, gets turned
into fibrin. Fibrin forms sticky fibres that create strong mesh
over the platelet plug. This solid clot traps red blood cells and
seals the wound
Fibrinolysis: once the injury heals, the clot is no longer
needed. An enzyme plasmin breaks down the fibrin fibres, this
clears the clot and restores normal blood flow
The lymphatic system
Immunity: defends the body against infection
Lymphatic drainage: removes excess fluid from tissues and
returns it to the blood
