EXCHANGE AND TRANSPORT IN ANIMALS: Detailed notes for a grade 9 student
The lung is part of the respiratory system as the lung breathes in oxygen and breathes out
carbon dioxide.
The lung has millions of alveoli. The alveoli is in charge of the diffusion of oxygen and carbon
dioxide (gas exchange).
The oxygen diffuses from the airs of the alveoli where the o2 has the highest concentration
to the blood vessels where the o2 concentration is the lowest so the oxygen can be
transferred to all the parts of the body to be used for aerobic respiration.
The co2 diffuses from the blood where the co2 concentration is the highest to the blood
where the co2 concentration is low so it can be breathed out.
To increase diffusion: short distance, large surface area, good supply of blood to increase the
concentration gradient, moist lining.
Red blood cells(erythrocytes) have a biconcave disc shape which gives them a large surface
area to carry as much oxygen as possible.
They have no nucleus, so a lot of oxygen is carried.
They also have a red pigment called haemoglobin which binds out onto oxygen in the lungs
to become oxyhaemoglobin, then later splits to form oxygen and haemoglobin to transfer
oxygen to the cells.
White blood cells like lymphocytes and phagocytes are part of the human immune system
that fight against diseases.
Lymphocytes are white blood cells that produce anti bodies to kill pathogens and release
anti toxins to reduce the effect and pain of diseases.
Phagocytes are white blood cells that change their shape to engulf the pathogens.
Platelets are small fragments of cells that form a clot over the skin.
The lung is part of the respiratory system as the lung breathes in oxygen and breathes out
carbon dioxide.
The lung has millions of alveoli. The alveoli is in charge of the diffusion of oxygen and carbon
dioxide (gas exchange).
The oxygen diffuses from the airs of the alveoli where the o2 has the highest concentration
to the blood vessels where the o2 concentration is the lowest so the oxygen can be
transferred to all the parts of the body to be used for aerobic respiration.
The co2 diffuses from the blood where the co2 concentration is the highest to the blood
where the co2 concentration is low so it can be breathed out.
To increase diffusion: short distance, large surface area, good supply of blood to increase the
concentration gradient, moist lining.
Red blood cells(erythrocytes) have a biconcave disc shape which gives them a large surface
area to carry as much oxygen as possible.
They have no nucleus, so a lot of oxygen is carried.
They also have a red pigment called haemoglobin which binds out onto oxygen in the lungs
to become oxyhaemoglobin, then later splits to form oxygen and haemoglobin to transfer
oxygen to the cells.
White blood cells like lymphocytes and phagocytes are part of the human immune system
that fight against diseases.
Lymphocytes are white blood cells that produce anti bodies to kill pathogens and release
anti toxins to reduce the effect and pain of diseases.
Phagocytes are white blood cells that change their shape to engulf the pathogens.
Platelets are small fragments of cells that form a clot over the skin.
