UNIT 4 - RESISTANCE & IMMUNITY Flashcards
Granulocytes (3)
- Neutrophils
- Eosinophils
- Basophils
Agranulocytes (2)
- Lymphocytes
- Monocytes
Importance of leucocyte count
Each leucocyte has a definite purpose and seeing changes in specific types can help diagnose a problem
Differential count
Used in diagnosis of an infection/disease on basis of an increase or decrease in numbers of specific types of WBC
Relative quantities of leucocytes in blood (5)
- Neutrophils (60-70%) - Lymphocytes (20-25%)
- Monocytes (3-8%)
- Eosinophils (2-4%)
- Basophils (0.5-1%)
Lymphatic system
Group of organs, vessels, and tissues that protect us from infection and keeps a healthy balance of fluids throughout the body
Plasma
Fluid portion of blood
Interstitial fluid
Fluid between tissues and cells (bathes tissues)
Lymph
Fluid in lymphatic vessels (mostly interstitial fluid) that bring back fluid from body and drain into circulatory system through two ducts in neck region
Lymph nodes
Located in lymphatic vessels that contain WBC to filter and cleanse the lymph of pathogens and abnormal cells before returning to circulatory system
Movement of lymphatic system (4)
- Interstitial fluid with the white blood cells enters lymphatic capillaries through small pores
- Fluid inside lymphatic capillaries (lymph) flows through lymphatic vessels throughout body
- Microbes and foreign particles present in circulating lymph encounter macrophages, dendritic cells, and lymphocytes that carry out various defensive actions within lymph nodes
- Lymphatic vessels return lymph to the blood via 2 large ducts that drain into vein near neck/shoulders
What happens to the majority of fluid that leaves the capillaries
The majority of fluid that leaves the capillaries is returned to the circulatory system, but approximately 15% remain in tissues as part of interstitial fluid and blood volume in arteries is 15% more than veins
What happens to this “lost fluid” and how is arterial volume restored
Restored to the circulatory system through lymphatic system
Functions of lymphatic system (4)
- Drains excess interstitial fluid to restore blood volume
- Protects against invasion through immune responses
- Transports dietary lipids and some vitamins from the gastrointestinal tract to the blood
- Return tissue fluid back to circulatory system
Drains excess interstitial fluid to restore blood volume
One way transport system that drains fluid from all body tissues and returns it to the blood at the left and right subclavian veins
Protects against invasion through immune responses
Lymph pass through nodes that contain WBC and initiate defensive and immune responses
Lymph
Fluid in lymph vessels, mostly just interstitial fluid in lymphatic vessels that bring back fluid from body and drain into circulatory system through two ducts in neck region
Nodes
Oval/bean shaped swellings situated throughout lymphatic vessels to filter fluid within vessels
2 ducts in neck region:
- Right lymphatic duct –> right subclavian vein
- Thoracic duct –> left subclavian vein
Structural characteristic of the circulatory system
Moves as a circuit with a pump
Structural characteristics of the lymphatic system
One way system and has no pump. The movement of lymph is due to pressure differences aided by muscular action (smooth/skeletal) and forced through vessels
Spleen
Contains the largest amount of lymphoid tissue in body and controls the level of white blood cells, red blood cells and platelets
Tonsils
Masses of lymphoid nodules in pharynx and functions in filtering and immunological role
Thymus
Small grainy lymphoid organ located behind sternum for maturating of certain WBC
Resistance & immunity
Refers to the body’s ability to protect itself from foreign substances and pathogens (avoid disease)
2 major lines of defense of the immune system
- Innate (inherited) non specific resistance
- Adaptive specific resistance
Innate (inherited) non specific resistance
First line of defense that provides protective mechanisms to all people and responds in the same way to all potential invaders
Types of innate (inherited) non specific resistance:
- External defenses: skin & mucous membranes, body secretions
- Internal defenses: antimicrobial proteins, phagocytosis, fever, inflammation
Skin and mucous membrane
Unbroken skin and mucous membranes act as mechanical barrier to bacteria and viruses
Mucous
Produced in respiratory tract to trap debris and germs swept out by cilia
Gastric juice
Acid and enzymes in the gut to kill off bacteria and virus
Tears
Flush the eyes to remove dirt and bacteria containing enzyme lysozyme
Saliva
Flushes inside of the mouth containing enzyme lysozyme and immunoglobin
Sweat and oil
Produced by the skin, where sweat flushes skin and deposits salt on skin surface and oil from sebaceous glands contain antimicrobial compounds
Antimicrobial proteins
Proteins present in plasma or produced by infected cells
2 principle components of antimicrobial proteins
- Interferon
- Complement
- They are both also part of adaptive specific resistance
Interferon
Protein produced by infected cells that bind to surrounding non-infected cells and cause them to produce substances that interfere with viral replication
Complement
Protein produced by the liver found in plasma that bind to bacterial cells to attract phagocytes and cause holes in bacteria walls and consequent rupturing
Phagocytosis
Involves various white blood cells (macrophages, neutrophils, dendritic cells) that engulf foreign materials upon contact aided by complement proteins and fevers (phagocytes function better at high temperatures)
Fever
An abnormally high body temperature commonly occurring during infections
Impact of a high temperature (4)
- Intensifies effect of interferon
- Increases phagocytic action
- Inhibits growth and multiplication of microbes
- Speeds up bodies repair and resistance mechanisms
Inflammation
Response by the body to tissue damage due to injury and/or infection to prevent spread of infection and prepare the area for repair and destroy toxins
Symptoms of inflammation (3)
- Localized pain
- Swelling (caused by WBC releasing histamine, prostaglandin, complement, etc)
- Redness/heat (caused by vasodilation and blood vessels more permeable so WBC move out quickly)
Process of inflammation (3)
- Blood vessels dilate bringing increased blood flow to injury
- Phagocytes migrate to the injury site and ingest microbes and other foreign substances
- Lymphatic drainage removes dissolved poisonous substances for healing
Antigen
Something that is able to trigger an immune response if body is foreign to it (Create a defence)
Antibodies
Protein produced by immune system to fight against specific invaders (antigens) like bacteria or viruses
2 characteristics of antigens:
- Immunogenicity
- Reactivity
Immunogenicity
Ability to provoke immune response
Reactivity
Ability of antigen to react specifically with antibodies it provoked
Epitope/antigen determinant
Region/site on antigen that acts as unique identifying markers on antigens that the immune system uses to recognize and respond to foreign substances
Adaptive specific resistance (4)
- Third line of defense that occurs in response to PARTICULAR pathogen that managed to get through all the non-specific defenses and unique to individual
- Involves activation of immune system
- Slower response as body must produce antibodies and active certain cells
- Cannot get started without aid of nonspecific phagocytosis occurring in innate immune response
Antigen presenting cells
Phagocytic cells that initiate the process of adaptive specific resistance (eg. Dendritic cells, macrophages, activated B cells)
Macrophages
Produced through differentiation of monocytes and roam throughout the body particularly concentrated in skin, lungs, mucous membranes, and around the intestine (where pathogens are most likely to enter the body)
Macrophages function (4)
- Phagocytose debris, foreign pathogens, dead/damaged cells
- Release antimicrobial chemicals to attract leucocytes to site of infection
- Present antigens to T cells and activate
- Initiate inflammation by releasing molecules (cytokines) that activate other cells
Immune response
The production of specific cell types and antibodies
Immunity
Function of lymphocytes found mainly in lymphatic system + spleen, bone marrow, blood, gut, skin tissues
2 categories of adaptive specific resistance
Cell mediated and antibody mediated
2 categories of lymphocytes
B-lymphocytes (B-cells); humoral immunity and T-lymphocytes (T-cells); cellular immunity
Humoral immunity (antibody-mediated)
Involves production of antibodies (immunoglobins) that react with an antigen on invading organism, and works against extracellular pathogens in fluids outside cells
Cellular immunity (cell-mediated)
Production of cytotoxic T cells that directly attack the invading organisms, and are particularly effective against intracellular pathogens, some cancer cells and foreign tissue transplants
B cells
Develops in red bone marrow and produce antibodies found in general location but mostly in nodes and differentiates into plasma cells and memory cells
Plasma cells
Differentiated B cells capable of secreting immunoglobulin or antibodies by leaving lymph node and enter general circulation
When is antibody production stopped
When all foreign antigens are destroyed, the antibody production will slow and stop
Memory B cells
Can remember the recognized antigen to improve secondary response
Are you forever immune if once infected
No, immunity may decrease over time if the person is not challenged by that specific antigen
Steps for antibodies to protect us from pathogens (5
)
- Complement activation
- Ab dependant cell mediated toxicity
- Neutralization: antibody binds and blocks virus
- Agglutination: clumping of bacteria and reduces number of growth
- Opsonization: coats the antigen with antibodies to signal phagocyte (makes pathogen tasty)
T cells
Develops in red bone marrow, then migrate to Thymus and does not produce antibodies, but develops effector T helper cells and effector cytotoxic T cell
Immunocompetence & immunotolerance
Ability to carry out specific immune responses & distinguish “self” from “non-self”
Cytotoxic T cell
Direct killing of intracellular pathogens and elimination of mutated and cancerous cells
Activation of cytotoxic T cell
Activated when it recognizes an abnormal or infected cell/virus then kills it
Helper T cell cells
Directs by secreting, signalling proteins and activates
Activation of helper T cells
When macrophages eats an infected cell it presents a small amount of its antigen to signal and activate the helper T cell
Memory T cells
Can remember the recognized antigen to improve secondary response
Cytokines
Activates B cells, T cells, macrophages
Interleukins
Stimulates B & T cell reproduction
Importance of cellular response (4)
- T cells recognize and respond to processed fragments of antigen displayed on surface of APC
- Targets cells infected with viruses, bacteria, or intracellular parasites
- Targets abnormal/cancerous cells
- Targets cells of infused or transplanted foreign tissue
Ways antibodies destroy/inactivate foreign substance in body (6)
- Direct opsonization
- Indirect opsonization
- Neutralizes
- Complement system
- Immobilizing bacteria
- Activation of anaphylactic system
Complement system
Antibodies activate complement system consisting of blood proteins that help immune system
Immobilizing bacteria
Binds flagella making it harder for bacteria to spread
Activation of anaphylactic system
Allergic reaction involving IgE which helps to localize the invading agents by swelling tissue and attracting immune cells
5 types of antibodies (6)
- IgG: Most common antibody in plasma
- IgA: Most common antibody in mucous membrane
- IgD: Has immunological functions
- IgE: Killing of worm parasites and allergic reactions
- IgM: Largest antibody and is the first to appear in response to initial exposure to antigen
- Ig is short for immunoglobulin
Immunization
Process by which resistance to disease can be induced or augmented
Induced
Stimulating immunity of body to a specific disease that has not been encountered yet to prevent infection achieved through vaccinations (active immunization)
Augmented
Supplementing/boosting bodies own response to particular disease achieved through injection of specific antibodies (passive immunization)
Types of active immunizations (3)
- Injection of dead organisms (eg, typhoid fever, diphtheria)
- Injection of moified toxins (eg, tetanus, botulism)
- Injection of live weakened organisms (Eg, measles, chicken pox)
mRNA
Teach our cells how to make a protein that triggers an immune response inside our bodies
Immunological tolerance
Ability for immune system to distinguish between self and non-self to prevents immune cells from attacking our own body’s proteins and tissues, generated during maturation of lymphocytes when B and T cells with reactivity to body’s own tissues die or inactivated
Autoimmune disease
Failure of the immunological tolerance
Autoantibodies
Antibodies that react with self-antigens (respond to body’s own proteins)
Autoimmune disease general facts (3)
- Frequency 5% in North America, more common in females
- Can be caused by production of autoantibodies (eg. Myasthenia gravis; targets neuromuscular junctions causing muscle weakness)
- Activation of cytotoxic T cells (Type I diabetes, multiple sclerosis, systematic lupus erythematosus)
Rheumatoid arthritis
Immune system attacks healthy cells in body by mistake and cause inflammation
Addisons disease
Immune system attacks adrenal glands and severely damage adrenal cortex which impacts production of steroid hormones cortisol and aldosterone
AIDS (4)
- Prevalence of 38.4 million worldwide; 63,000 in Canada
- HIV infects and kills helper T cells
- After prolonged incubation period, opportunistic infections occur and cancer
- Treatment is antiretroviral therapy
Opportunistic infections
Infections that occur more frequently and more severe in people with weakened immune systems (eg. Pneumonia)
4 major types of blood in humans
A, B, AB, O
How is blood type determined (3)
- By the presence of specific proteins and attached carbohydrates
- One group is attached to the RBC membrane: Antigen
- Other group is found in the plasma: Antibodies/agglutinins
- Antigens determine group group
Type A blood
A antigen, anti B antibody
Type B blood
B antigen, anti A antibody
Type AB blood
A & B antigen, no antibody
Type O blood
No antigen, Anti A & B antibody
Agglutination and hemolysis
Blood clotting that occurs if the RBC is placed into plasma that contains the opposite antibody and the destruction of RBC
Blood transfusions:
For any recipient to receive blood from a donor, there should be a direct match (A–>A, B–>B. O–>O. AB–>AB; preferable), or recipients plasma cannot contain the antibody that will cause the donor cells to agglutinate; in emergencies
Recipient blood group A
Possible donor is A or O
Recipient blood group B
Possible donor is B or O
Recipient blood group AB
Possible donor is AB, A, B, or O
Recipient blood group O
Possible donor is O
Universal recipient
Blood AB+
Universal donor
Blood O
Rhesus (Rh) antigen
Individuals with this antigen are Rh+, individuals without this antigen are Rh-. Most people are Rh+ and the Rh factor is important for pregnancy
Do people have Rh antibodies
No but if someone who is Rh- is exposed to Rh antigen, then the body will detect it as foreign and will make antibodies against it
Rh factor in pregnancy (3)
- First pregnancy: Father is Rh+, mother is Rh-, baby is Rh+ (born fine). Prior to and during birth, some of the baby’s RBC leak into mothers circulation
- Between pregnancy: Mother produces antibodies against Rh antigen from the baby
- Second pregnancy: If baby is Rh+, antibodies from the mother cross the placenta and cause agglutination and destroy the RBC of baby = hemolytic disease of new born. However, if baby is Rh- (like mother) there is no problem
Prevention of haemolytic disease of new born
Giving the mother immunoglobulin treatment after 1st birth to prevent the antibody production
A+
Agglutination with Anti A and Anti Rh
A-
Agglutination with Anti A
B+
Agglutination with Anti B and Anti Rh
B-
Agglutination with Anti B
AB+
Agglutination with Anti A, Anti B and Anti Rh
AB-
Agglutination with Anti A and Anti B
O+
Agglutination with Anti Rh
O-
No agglutination
