Transcript THE CIRCULATORY SYSTEM-blood

THE CIRCULATORY
SYSTEM
Objectives:
1.
2.
3.
4.
Explain the functions of the circulatory system
State the main components of the circulatory system.
Describe the structure and function of blood
Know what types of blood are compatible with each other
and why.
Three Main Components of
the Circulatory System
1. Fluid in which materials are
transported (i.e. blood)
2. Vessels to provide
controlled paths (i.e. veins,
arteries, capillaries)
3. A pumping device to move
the fluid around (i.e. heart)
BLOOD: IT’S ALIVE!
- An average adult has 5L of blood
Function of Blood
1. Transports oxygen and nutrients to cells
2. Transports carbon dioxide and wastes away from
cells
3. Helps maintain homeostasis:
– Transports chemical messages throughout the body (ex.
hormones),
– helps maintain acceptable fluid levels,
– helps maintain a constant temperature
4. Is part of the immune system, used to transport
immune cells throughout the body
Components of Blood
Blood cells are produced from
stem cells in your bone marrow
1) Erythrocytes (RBC’s)
• Made in the bone marrow
• Destroyed in liver and spleen
• Contain gas-binding haemoglobin and
iron; carry O2( combines with Fe) and
CO2
• No nucleus or mitochondria
• Blood types: different glycoproteins on
cell surface
• FOUR blood types: A, B, AB and O
• Surface ANTIGENS or markers consisting of
glycoproteins (proteins with attached
polysaccharides), are found on the plasma
membranes of red blood cells
• There are two types of surface antigens, A or
B
• The presence or absence of antigens A and B
on the plasma membrane of the rbc of a person,
determines that person’s blood type
• The body’s own blood type antigen(s) is
recognized by the immune system as “self”, but
other blood type antigens will be considered
“non-self” by the body’s immune system
• Within the blood plasma there will be
ANTIBODIES to the opposite blood type
• These antibodies have a complementary shape
to the antigen and will bind to it.
– eg. A person with antigen A on their red blood cells
will have antibody B (Anti-B) in the plasma
– A person with antigen B on their red blood cells will
have
– antibody A (Anti–A) in the plasma
BLOOD TYPE
ANTIGEN ON RBC’s
ANTIBODY IN
PLASMA
A
A
B
B
B
A
AB
O
AB
NONE
NONE
AB
• When incompatible blood types combine,
agglutination or clumping of red blood cells will
occur.
• The antibodies present in the recipient’s plasma
will attack and bind to the donated red blood cells’
antigens clumping the red cells together and
preventing them from circulating.
• This creates blockages in small capillaries
• For a donation to be successful, the recipient’s
plasma must NOT have an antibody that causes
the donor’s cells to agglutinate.
Blood Types
(NOTE: the antibodies in the plasma of the donor are not
considered since they are very diluted during the transfusion
and do not cause clumping.)

Blood Type
Can Receive
A
A and O
B
B and O
AB
O
A, B, AB and O
O
• Another surface antigen important in blood
typing is the Rh factor or Rhesus factor
• Rh+ means the antigen is present on red
blood cells (85% of people)
• Rh – means the antigen is absent on red
blood cells (15% of people)
• e.g. type B+ means type B blood with the Rh
factor present
• Rh+ has Rh antigen
• Therefore Rh+ has no Rh antibodies.
• Rh- has no Rh antigen
• Therefore Rh – has Rh antibodies.
• THEREFORE…
– Rh+ can donate to Rh+ only
– If Rh+ donated to Rh- the Rh antibodies in Rh- blood
would attack the antigens in the Rh+ blood being donated.
– Rh- can donate to Rh- and Rh+ because Rh- has no antigen
to be attacked and Rh+ has no antibodies to do the
attacking.
Blood Type
Can Receive
AA+
BB+
A- and OA+ A- O+ and OB- and OB+ B- O+ and OA- B- and OUniversal recipient
OO+ and O-
ABAB+
OO+
2) Leukocytes (white blood cells)
• Made in the bone marrow and lymph nodes
• Have a nucleus
• Different types
• Function: As part of the immune system,
they can produce antibodies to attack
pathogens or they can be phagocytic and
engulf pathogens.
3) Platelets
• Repair wounds by releasing clotting factors
(proteins) to help cells stick together
• No nucleus
• Produced in bone marrow
Your Task
• Read and complete the worksheet on
‘Blood and its Components’
• H/W complete worksheet on Blood
Typing
Plenary
1.
2.
3.
4.
5.
6.
What is the function of blood?
Name the two major components of blood.
What is the function of hemoglobin?
What is the function of red/white blood cells?
What is an antigen/antibody?
What is the difference between Rh-positive
and Rh-negative blood?
7. A person with A- blood is given blood from a
donor with O+ blood. What happens and why?