Circulatory and Immunity Flashcards

The fluid portion of blood is Plasma, the fluid where the RBCs, WBCs and platelets are suspended. Plasma itself is made up of water, salt and the things suspended throughout like (Amino acids, Carbs, Enzymes, etc.). It keeps cells from clumping and keeps them moving easily

Red blood cells (erythrocytes) are specialized cells that transport oxygen, contain hemoglobin and don't have a nucleus. RBC's bi-concave increases surface area and aids their ability to move through small blood vessels. They are produced in red bone marrow and have an average life span of 120 days. When they carry oxygen they are bright red, when they don't they are dark blue-red (appear blue in veins).  Anemia is a condition where there are too few RBC's or too little hemoglobing in them.

Also called Leucocytes, WBC's respond to infections in a body. They have a nucleus and appear colourless. They make up 1% of your total blood colume and can increase to 2% when your body is fighting an infection.

Platelets are fragments of cells that form when larger cells in the bone marrow break apart. They contain no nucleus and break down quickly in blood. They play a key role in clotting to prevent excessive blood loss after injury. They activate fibrin from fibrinogen to catch RBC's to stop blood loss.

The Lymphatic system is a system of vessels that work with the capillares and veins in the circulatory system. It maintains the balance of fluids in the body (water/plasma) and works with WBC's to protect the body against infection (transports them). The lymphatic vessels are not sealed off and have spaces that allow substances in or out.

It is made up of interstitial fluid (fluid between cells, basically plasma just in lymphatic system), it is a colourless or pale yellow and it's composition is much like plasma. As blood circulates, some plasma escapes from the capillaries and becomes a part of interstitial fluid. This interstitial fluid is absorbed into lymphatic vessels and eventually rejoins the circulatory system (dumps into veins near the heart). The circulatory system is a continuous circuit, but lymph forms in close ended tubes in the capillary beds (lymph nodes)

Lymph nodes are glands found throughout the lymphatic system. They store lymphocytes ("baby WBC's") while they mature and contain macrophages that trap and detroy bacteria that circulates inside the body. Infections can cause the immune system to increase the number of macrophages and lymphocytes in lymph nodes, which is why your jaw or armpits can swell when you're ill.

It is the phsycial line of defense which is non-specific (destroys anything that isn't from the body). It includes the skin, mucus membranes, hair and cillia. The low pH of skin kills germs and Lysozyme secreted in bodily fluids also kills bacteria.

The second line of defense is non specfic macrophages (kill things not made by body). They come into play only if an invader gets past the first line, are specialized blood cells that eat the invader through the process of phagocytosis. Neutrophils are a specific type of macrophage that attack infected cells destroying it and the microbes (the dead fragments are called pus). When macropahges come into play you may feel iflammatory response such as Redness (due to more blood flow), heat (to cook out invader), pain and swelling (help leukocytes travel/diffuse).

As soon as the pathogens enter the bpdy, they activate compliment proteins already floating around in the blood. These proteins work together to form a coating around the pathogen and a different protein will come and puncture the cell, filling it with water and making it burst. Then a last group of proteins attaches to the cells that have not burst and acts as a neon sign for the leukocytes. This intrusion also stimulates the production of antibodies.

Antibodies are proteins designed to recognize specific antigens of a virus. They Flag, Slow, Neutralize toxins or kill pathogens similar to how complement proteins do. Antigens are like nametages of a protein and every protein has them.

There are T cells which are produced in the bone and stored in the thymus and B cells which are made and stored in bone marrow.

A macrophage will devour the pathogen throught phagocytosis and will present the antigen of the pathogen to helper T cells. The helper T cells make memory helper T cells and activate the cytotoxic B and T cells. The B cells change into plasma cells to create antibodies and make memory cells in case the pathogen is detected again. Antibodieswill attach to the virus and infected body cells to signal their destruction. The T cells will go and directly destroy infected body cells and viruses.

If a foreign body uses it's antigen to attach to a cell and have the cell engulf it, it will kill the cell. Antibodies binding to antigens helps prevent this from occuring.

Once the second line of defense (macrophages) have done their job, the antigen of the invader sticks out of the macrophage cell. Helper T cells will recognize the shape and send out a chemical called Lymphokine. Lymphokine causes B cells to divide rapidly and produce the antibody to the invader. Helper T cells also activate killer (cytotoxic) T cells.

They puncture the cell membrane of an intruder and kill it. They are also the cells that eat mutated cells before they become cancerous. Killer T Cells will attack a transplanted organ and must be supressed with an immunosupressant drug (tricks body to accept organ).

Supressor T cells will inhibit immune response. Most B cells and T cells will die off after a few days and some will stake out the body for a long time. The long term cells are Memory B cells that instantly make antibodies if the infection comes back.

During the "battle", memory B cells are created, they hold an imprint of the antigen of that invader. These memory B cells are not killed off after an immune response has ended, they will stay and the next time the same invader enters the body the memory B cells will initiate an immune response right away.

A,B,AB, and O and they can be Rh positive or negative. They are different due to the absence or presence of antigens on their RBC's surface and antibodies in the plasma. Blood type A has A antigens and anti-B antibodies, B has B antigens and anti-A antibodies, AB has AB antigens and no antibodies (for blood) hence why it is called the universal acceptor (AB+) and O has no antigens (O- is universal donor) and both Anti-A and B antibodies.

If an incompatible blood type enters your body it will lead to agglutination. Agglutination is the clumping of RBC's that can block circulation and cause severe organ damage (antibody holds red blood cells).

If a person has a rhesus factor they have a positive blood type (RH+). If they don't they are RH- (85% of Canadians are RH+). Rh- can donate to Rh+, but Rh+ cannot doante to Rh- (Rh- has anti rhesus antibodies). This only poses a problem during transfusions and pregnancy.

Erythroblastosis fetalis occurs when a mother has two babies that isare Rh+ but she is Rh-. During the first pregnancy her body builds antibodies and the baby is ok, but during the second her antibodies will attack the baby unless she is given Rh serum (RHoGAM) after birth to destroy the antigens and stop antibody formation.

T cells or antibodies attack the body's own cells as if they were foreign antigens. An example is Rheumatoid arthritis when the things around joints are attack which causes inflammation of the joint lining. Allergies occur when your immune system exaggerates a response to a harmless material - such as pollen,mould, certain foods, animal furs, etc. There is acute which occurs within seconds and leaves in 30 minutes and chronic which is set off by T cells, slower but lasts for a longer. time

Acquired immune deficiency syndrome, is when the HIV virus destroys the bodies helper T cells and weakens the immune system. This weakens the body and makes it susceptible to viruses the immune sytem could usually stop. It is spread through the exchange of bodily fluid.