Diagrams from Wednesday
Injured tissues and platelets
release Prothombin Activator
(an enzyme) (vitamin K required
for the production of Prothombin)
Prothrombin Activator
catalyzes the conversion of
Prothrombin to Thrombin.
(Ca++ is necessary for this step)
Prothrombin
Activator
+ Ca++
Thrombin
Prothrombin
Thrombin is an enzyme
that acts like a pair of
scissors, cutting short
amino acid ends off
Fibrinogen molecules
Fibrinogen
Fibrin Fragments join together
end to end to form long fibers.
Fibrin fibers form the
framework of the clot.
Fibrin Fragment
1. Blood vessel is punctured.
2. Platelets congregate and
form a plug.
Prothrombin activator
3. Platelets and damaged
tissue cells release
prothrombin activator,
which initiates a cascade
of enzymatic reactions.
Prothrombin
Fibrinogen
4. Fibrin threads form and trap
red blood cells.
Ca2+
Ca2+
Thrombin
Fibrin threads
from
heart
Arterial end
Blood pressure is
higher than
osmotic pressure.
Net pressure out.
Venous end
Osmotic pressure
is higher than
blood pressure.
Net pressure in.
Tissue fluid
water
oxygen
amino
acids
glucose
water
carbon
dioxide
wastes
arteriole
osmotic pressure
blood pressure
salt
plasma
protein venule
to
heart