Blood & Immunity Blood
Plasma Watery portion (90% water) of blood About 55% of the blood Contains many proteins including antibodies and albumin
Cells Comprise about 45% of blood Erythrocytes (red blood cells) are red blood cells and are the most abundant blood cell Red blood cells are made in the bone marrow
Erythrocytes Hemoglobin Red pigment Carries oxygen and becomes bright red Contains iron
Erythrocytes High altitudes can lead to an increase in RBC numbers Anemia is when you don t have enough RBCs
Thrombocytes aka platelets Second most abundant cell in blood Produced in the bone marrow Responsible for clotting Blood clotting Smooth muscle contraction is a reflex following a blood vessel injury Platelet plug forms as platelets stick to the injury Clotting occurs with the help of clotting factors
Complex Clotting Pathway
Clotting Clotting factors are made in the liver Vitamin K is needed for making some of the clotting factors After the vessel injury is repaired, the clot will break down Clotting Pathology Thrombus A clot occurs when you DON T need it. This could be in a coronary artery and lead to a heart attack, or in a brain blood vessel leading to damaged brain, or a stroke Embolus/Embolism A thrombus can become dislodged and carried to another location where it gets stuck.
Hemophilia Clotting Pathology Genetic disease in which one of the clotting factors (proteins) is missing. Blood clotting is abnormal Transfusions are needed to replace the missing clotting factor Blood Cells Leukocytes = White blood cells Fewest in number Can exit the bloodstream to fight infection Life span can be quite short to many years depending on the battle they are fighting Made in the bone marrow, lymph node, tonsils and spleen
Resistance to Disease Nonspecific resistance are protective mechanisms that you are born with to fight off any type of infection or damage Nonspecific Resistance Physical and Chemical barriers Skin, mucous membranes Hairs and cilia Hydrochloric acid in stomach Various anti-microbial enzymes
Nonspecific Resistance to Disease Phagocytosis WBCs can eat and destroy damaged cells and microorganisms
Nonspecific Resistance to Disease Inflammation Isolates and prevents spread of infection. Prepares site for healing
Specific Resistance to Disease = Immunity Develops over time Specific response for every antigen (e.g. microorganism) you encounter Has memory to fight off subsequent encounters quicker and better
Antigen An antigen is a substance capable of eliciting an immune response Examples include microorganisms and the toxins they make Cellular immunity Based on Lymphocytes, a type of white blood cells
Lymphocytes T lymphocytes or T cells specifically recognize antigens and destroy them Especially respond to intracellular microorganisms, viruses, cancer cells, parasites T cells have a memory response on subsequent encounters with the same antigen
Lymphocytes B lymphocytes or B cells work in immunity by producing ANTIBODIES Antibodies Antibodies are specific proteins that specifically attach to the antigen and signals the body that it has an invader that needs to be destroyed B cells what make the specific antibodies have memory so that subsequent antigen exposures result in rapid and big destruction of the antigens
Vaccination Vaccination works because of immunity with its memory An antigenic piece that is altered so that it doesn t harm you, is injected as a vaccination Upon subsequent exposures to the real antigen, you mount such a big immune response, that you rarely get sick
AIDS Acquired Immune Deficiency Syndrome Cause is HIV = Human Immunodeficiency Virus HIV selectively infects & replicates in T cells Consequences of T cell destruction is crippling of the immune system
Course of the Disease HIV + means that you have been exposed to the virus. You may or may not be sick Symptomatic stages occur when your T cell count decrease and include flu-like symptoms, night sweats and weight loss Full blown AIDS occurs when the T cell counts are so low that you acquire an opportunistic infection because you don t have a very functional immune system.
Transmission of HIV Blood (transfusions, shared contaminated IV needles) Sexual Across placenta (mom to baby) The virus is quite fragile OUTSIDE of the body
Prevention of HIV Infection Abstinence, proper use of latex condoms Sterile needles for injections Blood supplies are screened for HIV in the U.S. Anti-viral drugs Treatment Antibiotics for opportunistic infections Treatments are very expensive