Unit 11 – Physiology of Human Body Systems
M2 – explain the need for transport systems in a multi-cellular organism
As multicellular organisms, we have more than one cell, so we require all these cells to be working as
efficiently as they can. We need a transport system as without it, diffusion would be too slow to
remove waste and deliver nutrients to the billions of cells in our body. As humans, we have a small
surface area to volume ratio and again diffusion would be too slow. Diffusion is slow already as it is
minus the fact of diffusion distances, as the surface area to volume ration increases, the even slower
diffusion will be, and the cells won’t get their nutrients and get rid of their waste in time for it to
carry out its job efficiently. Multi-cellular organisms would not be able to receive these substances
through their external surface as before it can reach certain cells underneath it would have already
been used up before getting there. Multicellular organisms have different cells that carry out
different functions unlike a unicellular organism that only requires its one cell to carry out its
function. And so, because of this, cells in a multicellular organism have different levels of activity as
they carry out different tasks. For example, muscle cells might be working more when exercising
compared to when they are resting. Because of this, during exercise they require more substances to
be sent to the actively working cells, so they can efficiently carry out their function.
In humans and other mammals, the pump of the entire body system is the heart. Many different
substances are carried within the blood and the blood flows through blood vessels.
The heart supplies oxygen and nutrients to tissues while removing waste and carbon dioxide. The
heart consists of a double circulatory system with the right side taking deoxygenated blood from the
heart to the lungs via the pulmonary artery. The left side pumps oxygenated blood back to the heart
via the pulmonary vein. The blood then is pumped to the entire body via the aorta and returns back
through the vena cava to start again.
…………………………………………………………………………………………………………………………………………………….
Thank you for previewing the example, feel free to buy the singular task, or the Unit 10 bundle xxx
M2 – explain the need for transport systems in a multi-cellular organism
As multicellular organisms, we have more than one cell, so we require all these cells to be working as
efficiently as they can. We need a transport system as without it, diffusion would be too slow to
remove waste and deliver nutrients to the billions of cells in our body. As humans, we have a small
surface area to volume ratio and again diffusion would be too slow. Diffusion is slow already as it is
minus the fact of diffusion distances, as the surface area to volume ration increases, the even slower
diffusion will be, and the cells won’t get their nutrients and get rid of their waste in time for it to
carry out its job efficiently. Multi-cellular organisms would not be able to receive these substances
through their external surface as before it can reach certain cells underneath it would have already
been used up before getting there. Multicellular organisms have different cells that carry out
different functions unlike a unicellular organism that only requires its one cell to carry out its
function. And so, because of this, cells in a multicellular organism have different levels of activity as
they carry out different tasks. For example, muscle cells might be working more when exercising
compared to when they are resting. Because of this, during exercise they require more substances to
be sent to the actively working cells, so they can efficiently carry out their function.
In humans and other mammals, the pump of the entire body system is the heart. Many different
substances are carried within the blood and the blood flows through blood vessels.
The heart supplies oxygen and nutrients to tissues while removing waste and carbon dioxide. The
heart consists of a double circulatory system with the right side taking deoxygenated blood from the
heart to the lungs via the pulmonary artery. The left side pumps oxygenated blood back to the heart
via the pulmonary vein. The blood then is pumped to the entire body via the aorta and returns back
through the vena cava to start again.
…………………………………………………………………………………………………………………………………………………….
Thank you for previewing the example, feel free to buy the singular task, or the Unit 10 bundle xxx
