Download Tissues and Organs

Tissues and Organs
What are they and why does it matter?
Introduction
• Animals and plants are made up of cells but a
big lump of cells isn’t going to be able to
organise itself to do all of the things a living
creature needs to do
• Cells are therefore arranged into tissues,
organs and ultimately organ systems to make
sure these things can happen
Outline
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What is a tissue?
What is an organ?
What is an organ system?
Why does it matter?
What is a tissue?
• A collection of cells
gathered for a particular
function, e.g.
– Heart muscle
– Fat cells
– Nerve cells in the surface
of the brain
What is a tissue?
• Often made up of only a
few cell types (even just
one) that are grouped
together in order to
perform this one
function
What is a tissue?
• Rather than taking oxygen and nutrients to
individual cells, the blood transports these
things to groups of cells around the body
• This is why you will hear that blood takes
them to the tissues. This is referring to all
the groups of cells around the body
What is an organ?
• An organ is a group of
tissues gathered
together for a particular
task, e.g.
– The heart is made up of
muscle, valves, coverings
and chords. Each bit has
a different function, and
they work together to
perform the task of
pumping blood around
the body
What is an organ?
• An organ is a group of
tissues gathered
together for a particular
task, e.g.
– The brain is made up of
nerve cells in the brain,
special immune cells,
and other helper cells so
that the brain can
control the activity of
nerves in the body
What is an organ system?
• When lots of organs are linked together to
perform one bigger purpose, it is called an
organ system, e.g.
– The heart and blood vessels (and lungs) are linked
together to form the circulatory system
– The brain, the spinal cord, their coverings and the
fluid around them are linked together to form the
central nervous system
So what?
• If everything were a big, disordered mess, the
body wouldn’t achieve anything
• Instead, everything is specially designed to
work together
– Each cell performs a job
– Cells together form a tissue to perform a function
– Tissues together form an organ to perform a task
– Organs together form an organ system to make
sure a particular purpose is fulfilled
So what?
• And all the organ systems together form a
body, so that you can live, breathe, create…
• But without all this clever organisation, you’d
just be a messy lump of cells.
• So it’s rather useful, hey?
Any questions?
Further reading:
• Alberts B, Bray D, Hopkin K, Johnson A, Raff M, Roberts K,
Walter P (2009) Essential Cell Biology. 3rd Ed. New York:
Garland Publishing
For more information, don’t forget to visit www.blobs.org