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0:00
Welcome to this lecture.
I'm Dr. Lauren Lemkus
and I'm a haematopathologist
at the University of Cape
Town, in South Africa.
0:10
Imagine someone who
frequently gets nosebleeds
for no reason,
or who bruises easily
from minor bumps.
These might seem like
small annoyances,
but they could actually be
signs of a bleeding disorder.
For instance, a person
might have a condition
that affects their
blood's ability to clot,
leading to these frequent,
and sometimes unexplained,
bleeding episodes.
In this lecture, I hope
to give you an overview
of how the body
prevents bleeding,
what can go wrong
in the process,
and provide a few clinical
examples to illustrate how
patients with bleeding
disorders may present.
0:44
Blood carries essential
nutrients and oxygen
that our bodies need
to function properly.
It travels through tubes
called blood vessels,
delivering these supplies to
different parts of the body.
When a blood vessel is damaged,
blood can leak out,
causing bleeding.
Most of the time,
bleeding is minor
and is quickly stopped by
components of blood itself.
Haemostasis is a term given
to the physiological process
that prevents and stops bleeding
when blood vessels are injured.
The normal haemostatic response
to the damaged blood vessel wall
depends on a closely
linked interaction between
the blood vessel wall,
circulating fragments of
cells called platelets,
and proteins called coagulation,
or clotting, factors.
When you accidentally
cut your finger
with a kitchen knife,
at first blood
starts coming out,
but soon it slows down and stops
as your body uses platelets
and clotting factors
to form a protective plug,
or scab, over the cut.
Platelets stick together
and form a plug
at the site of the
injured blood vessel.
The proteins or clotting
factors then interact
to form a sticky, net-like
substance called fibrin,
which holds the
platelets in place
and allows healing to occur
at the site of injury,
while preventing more blood
from escaping the blood vessel.
Without sounding too dramatic,
