The Circulatory System Objectives: Explain the difference between an open and closed circulatory system. State what components make up the blood and what the function of each of these components is. Explain how blood typing works.

Why do we need a Circulatory System? Single celled organisms and simple multicellular organisms don’t need a circulatory system….oxygen and other nutrients can diffuse directly into all cells. In more complicated organisms, some cells don’t come in contact with the external environment. A system is needed to bring oxygen and other nutrients to these cells, and also to remove waste products from the cells. All circulatory systems have a transport fluid, a network of tubes, and a pump.

Types of Circulatory Systems Two types of systems are: Open Circulatory System (insects and crustaceans) blood is pumped through a main blood vessel into a system of connected body cavities where it transfers oxygen directly to the surrounding cells. The blood then returns to the heart. A slow system, best suited to small organisms Closed Circulatory System (vertebrates and annelids) The blood is always contained within blood vessels. It is pumped from the heart to the body tissues, where oxygen diffuses out of the blood vessel to the tissue. The blood is pumped back to the heart. A faster system

Open vs Closed Systems

The Blood The fluid portion of blood is called plasma and rest is made up of different kinds of cells. Plasma: 55% of blood Made up of water, gases, proteins, sugars, hormones etc. Important proteins include fibrinogen (used in clotting), globulins (like immunoglobulins which are antibodies) and albumins (maintain blood volume and pressure)

Red Blood Cells Called erythrocytes, they have no nucleus and make up 44% of your blood. RBC’s contain the protein hemoglobin which binds oxygen. Each RBC has about 280 molecules of hemoglobin. Erythrocytes are formed from stem cells in the bone marrow. As they mature they lose their nucleus to make room for more hemoglobin. After 120 days, RBC’s die and are broken down by the liver.

Anemia CBC = Complete Blood Count – performed to count the number of RBC, platelets, and leukocytes Lower than normal levels of RBCs indicates anemia Symptoms = low energy Causes = injury, internal bleeding, low iron, diseases

White Blood Cells Called leukocytes and make up 1% of the blood volume (can double if you are fighting an infection). All white blood cells appear colourless and have a nucleus. Some types of WBC’s include macrophages which can diffuse out of the blood vessels to engulf pathogens and lymphocytes which play a role in acquired immunity.

Platelets Cell fragments created by larger cells in the bone marrow. Used in blood clotting

Blood Types Discovered in 1901 by Karl Landsteiner Determined by the presence or absence of sugars, referred as markers (act as antigens) Two markers: A and B Type A blood has marker A Type B blood has marker B Type AB blood has both markers = universal recipient Type O blood has neither marker = universal donor

In order to determine the compatibility of a donor’s and recipient’s blood, there are two main systems for typing blood:   1. ABO System 2. Rh System

1. ABO Blood Typing System the most common system of blood typing FOUR blood types in this system: A, B, AB and O the ABO system was once used for chemical identification of a person; we now use DNA 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

Fill in Table from board… BLOOD TYPE ANTIGEN ON RBC’s ANTIBODY IN PLASMA A B AB O

AGGLUTINATION:   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. the Y shaped antibodies bind to two sites at once, clumping the red cells together and preventing them from circulating. this creates blockages in small capillaries, and results in shock, hemolysis, kidney failure and even death. for a donation to be successful, the recipient’s plasma must NOT have an antibody that causes the donor’s cells to agglutinate.

BLOOD DONATION TABLE: Blood Type of Recipient (antibodies) Blood Type of Donor (antigens) A B AB* O** O **

You must look at the compatibility of the donor’s antigens (red blood cells) with the recipient’s antibodies (plasma) to determine if clumping will occur. For example, if the donor’s cells have Antigen A and they are transfused into a person having Antibody A (Anti-A) in their plasma, clumping will occur. Antigen from donor (Red Blood cells)     Antibody from Recipient (Plasma)  (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.)

Summary: Blood Type Can Receive

2) Rh FACTOR in Blood Type 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

A little explanation… 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.

UNIVERSAL DONOR AND UNIVERSAL RECIPIENT: Type O- is the “Universal Donor” (can donate blood to anyone) because it has no antigens to be attacked by antibodies   Type AB+ is the “Universal Recipient” (can receive blood from anyone) because it has no antibodies to react against a donors antigens

TRANSFUSIONS & DETERMINING BLOOD TYPE: It is critical to determine compatibility of donor and recipients’ blood before administering a transfusion. The blood is typed using sera (as below) and then the donor and recipient blood is actually mixed and observed on a slide to be sure.   The agglutination reaction (clumping) is used to determine blood type by using Anti-A, Anti-B and Rh serum to mix with blood. Anti-A serum contains antibody A which will clump with “A” blood cells. Anti-B serum contains antibody B which will clump with “B” blood cells. Rh serum contains the anti- Rh antibody and will clump with Rh + cells. The clumping pattern will indicate blood type.

UNIVERSAL DONOR is O – (no antigens) UNIVERSAL RECIPIENT is AB + (no antibodies)

Rh FACTOR AND PREGNANCY: Scenarios:   Mother Rh+ Baby Rh+ = fine; the same Mother Rh – Baby Rh – = fine; the same Baby Rh – = fine; because baby has no antigen to be attacked Baby Rh+ = trouble; baby’s Rh antigen causes mother to produce antibodies against it 

Rh factor becomes important when an Rh – woman marries an Rh + man and becomes pregnant with an Rh + baby. The mother has Rh – blood, but does not normally have Rh antibodies in her plasma. However, the baby’s Rh + antigens can leak across the placenta and enter the mother’s blood stream. She begins to produce Anti-Rh antibodies which will attack any Rh + blood cells.   Usually the first Rh+ baby is fine. However, in any subsequent pregnancy with an Rh+ baby, the mothers Anti-Rh antibodies will cross the placenta and destroy the baby’s red blood cells causing hemolysis the rupturing of red blood cells. 

This is called Hemolytic Disease of the Newborn because hemolysis continues after birth. Due to the destruction of red blood cells, excess bilirubin in the blood can cause brain damage, mental retardation or even death. Treatment: An injection of Anti-Rh immunoglobulin is given to the mother midway through the pregnancy or within 72 hours following birth. This injection destroys any of the baby’s red blood cells which have entered the mother’s blood before these cells can stimulate her immune system to form Anti-Rh antibodies. This protects future Rh + babies.   NOTE: Anti-Rh antibodies are much smaller than Anti-ABO antibodies so they can cross the placenta, while the anti-ABO’s can’t.

Consolidation Read and annotate notes: Page 478-481, do #1-5 on page 481 Page 482-486, do #1-7 on page 486 Complete blood components table Complete Blood Type worksheet