Download Blood Type - Van Buren Public Schools

Blood Type
Learning Goals
I CAN …
…identify how blood types are
determined
…explain which blood transfusions
are safe
…explain which blood transfusions
would be life threatening
…explain why Rh-negative mothers
need prophylactic treatments to
protect their fetus
Determining Blood Types
I. How Blood Types are Determined
A. The different blood types are determined by
a n t i g e n s found on the surface of red blood
cells.
Antigens – s u b s t a n c e t h a t , w h e n
introduced to the body, causes the
formation of antibodies against it.
1. Usually antigens are found on foreign substances but
our body’s cells have p e r s o n a l i z e d a n t i g e n s
as well
2. The purpose of antigens i s t o a l l o w t h e b o d y
to tell the difference between tissues
that belong and tissues that need to
be attacked by the immune system
Determining Blood Types
B.Once the body detects a foreign antigen i t
produces antibodies to stop the
antigen from causing further
damage in the body.
Antibodies – s u b s t a n c e s p r o d u c e d b y
the body that destroys or
inactivates a specific substance
(antigens) that have entered the
body.
1. Amazing the body i s a b l e t o d e v e l o p
antibodies to every antigen known
to man.
2. Tissue/organ rejection occurs w h e n t h e
immune system of the recipient
makes antibodies against the
transplanted organ.
Determining Blood Types
C.The antigens on the surface of your red
blood cells are determined g e n e t i c a l l y .
1. The pattern of inheritance is
c o d o m i n a n c e , which means that there
are no recessive alleles; h e t e r o z y g o u s
individuals express both traits
simultaneously.
Determining Blood Types
2. Some examples of how
these blood types could
be inherited are:
Possible Allele
Combinations
Blood Type
Type A
IAIA, IAi
Type B
IBIB, IBi
Type AB
IAIB
Type O*
ii
* Type O alleles
code for no
antigens. If this
allele is inherited
with an allele for
antigen A or
antigen B then
the blood type
reflects the
presence of those
antigens.
Determining Blood Types
3.When a person inherits the antigens,
they automatically inherit the antibodies
for the antigens they don’t have.
If your Blood type
is…
Then you have …
Type A
B antibodies
Type B
A antibodies
Type AB
NO antibodies
Type O
A and B Antibodies
Blood Types
Blood Transfusions
II.Blood Transfusions
A. The first transfusions were unsuccessful because
they knew nothing of antigens and
antibodies.
B. Doctors first started “typing” patients by t a k i n g
small samples from both donor and
recipient, combining them outside
the body, and observing for
agglutination.
C. Now that we understand how the antigenantibody complex works, we have developed
ways t o t y p e b l o o d b e f o r e t h e r e i s
blood contact between donors and
recipients.
Blood Transfusions
Universal donors – p e o p l e w i t h T y p e O
blood that contains no antigens to
interact with anti-A or anti-B
antibodies
Universal recipients – p e o p l e w i t h T y p e
AB blood than contain no antibodies
to interact with either donate Type
A or Type B blood
D. When blood types mix and the result is that
antigens are present with their antibodies,
a g g l u t i n a t i o n occurs.
Agglutination – p r o c e s s i n w h i c h
antibodies cause antigens to clump
or stick together
Blood Types
Rh Factor
III.The Rh System
A. Another type of antigen was discovered in
the blood of the Rhesus monkey and then
our blood.
Rh-positive – r b c ’ s t h a t c o n t a i n a n
antigen called Rh factor
A+, B+, AB+, and O+ blood types
Rh-negative – r b c ’ s t h a t d o n o t
contain the antigen called Rh
factor
A-, B-, AB-, and O- blood types
Rh Factor
B. The difference between the Rh antigens
and the AB antigens is that t h e b o d y
doesn’t naturally make anti-Rh
antibodies
1. If Rh antigens are introduced into a Rhnegative person t h e b o d y w i l l m a k e
anti-Rh antibodies
2. During pregnancy if a f e t u s i s R h
p o s i t i v e ( d u e t o i t s g e n e t i c s ) and
the m o t h e r i s R h n e g a t i v e problems
MAY occur during future pregnancies.
Rh Factor
a.The first pregnancy when a f e t u s i s R h p o s i t i v e and the m o t h e r i s R h negative: the baby’s Rh antigens
will stimulate its mother’s blood to
make Rh antibodies
b.Subsequent pregnancies when the f e t u s i s
R h - n e g a t i v e the antibodies in the
mother’s blood will have no effect
on the fetus
c.Subsequent pregnancies when the f e t u s i s
R h - p o s i t i v e the a n t i b o d i e s t h a t
developed in the mother’s blood
will agglutinate the fetus’ blood
and cause erythroblastosis fetalis.
Rh Factor
Rh Factor
Erythroblastosis fetalis – c o n d i t i o n o f
a fetus or infant caused by the
mother’s Rh antibodies reacting
with the baby’s Rh antigens.
Characterized by mass
agglutination and resulting in life
threatening (for the fetus)
circulation problems
3. Erthryoblastosis can be avoided i f
during a first pregnancy a Rh negative mother is treated with
RhoGAM, which keeps her from
producing Rh antibodies.