blood and immunity

SECTION 1:BLOOD COMPONENTS:

Blood is a tissue designed to carry out homeostasis\
HOMEOSTASIS-keeping a constant solute-solvent balance

MAJOR FUNCTIONS OF BLOOD IN THE HUMAN BODY:

1.Serves as the liquid matrixof blood tissue
2.Transport products of digestion: amino acids, simple sugars, fats, vitamins, salts and water.
3.Transports nitrogenous waste(urine formation -urea) 4.Transports dissolved gases(CO2 and O2)
5.Transports hormones, enzymes
6.Regulates body temperature(blood helps to dissipate heat)
7.Balances pH levels(7.4)
8.Blood protects body from invading microbes(white blood cells)
9.Responsible for blood clotting(platelets)

MAJOR COMPONENTS OF THE BLOOD INCLUDE:

BLOOD CELLS-the cellular portion of the blood that includes highly specialized red blood cells, white blood cells, and platelets
I) PLASMA
II) RED BLOOD CELLS/ ERYTHROCYTES
III) WHITE BLOOD CELLS/LEUCOCYTES
IV) PLATELETS/THROMBOCYTES

BLOOD PLASMA

Appearance:
-clear, straw colored liquidportion of the blood
-90% water and 10% dissolved fats, salts, sugars, and plasma proteins
Number:-55%of blood is made of plasma
FUNCTIONS
1.Contains Plasma proteins such
as:→albumin-maintains blood and osmotic pressure→globulin -makes antibodies, and antitoxins, and transport of proteins around body
→fibrinogen and prothrombin -used in blood clotting
2.Also carries
▪nutrients(amino acids, fatty acids, sugar)
▪gases(nitrogen, oxygen, carbon dioxide)
▪mineral salts(calcium, sodium, potassium) and vitamins
▪enzymes, hormones
▪waste products
-urea

RED BLOOD CELLS / ERYTHROCYTES:

Appearance:
-have no nucleuswhen mature
-small, round, bi-concave disks(narrow in the center)
Origin:
-produced in red bone marrowand become filled with hemoglobin that pushes out the nucleus
-when worn out they are destroyed by phagocytes, and broken down in the liver and spleen
-continually produced and die (life span 120days)Number:
-RBC make up 45%of blood
-more red blood cells than any other cell in the body(Ratio RBC to WBC is 600/1)
FUNCTION:
1.Transport oxygen and small amount of carbon dioxide through the use of hemoglobin to and from the lungs to cells
Recall: oxygen + hemoglobin \= oxyhemoglobin(bright red)
2.Helps maintain a stablepHfor the body (blood buffer \= 7.4 stable pH)

DISEASES OF RED BLOOD CELLS:

ANEMIA
Anemiais a condition that develops when your blood lacks enough healthy red blood cells or hemoglobin.Hemoglobin is a main part of red blood cells and binds oxygen. If you have too few or abnormal red blood cells, or your hemoglobin is abnormal or low, the cells in your body will not get enough oxygen.
Symptoms:
i)insufficient red blood cells to carry oxygen to all cells of body or insufficient hemoglobin
ii)cells are not receiving enoughoxygeniii)tired, lack of energy
Cause:
MINERALdeficiency: too little ironin the diet
Treatment:Easily cured by eating iron rich foods Injections of vitamin B1or iron supplement
SICKLE CELL ANEMIA:Sickle Cell Anemia is a hereditary genetic disorder, causes by an abnormal form of hemoglobin-sickle shaperather than circular shape
Problem:
-poor O2 transport
-sickle shaped cells can become lodged in blood vessels and lead to blood clots

WHITE BLOOD CELLS / LEUCOCYTES:

Appearance:
-varied of colorless blood cells
-contain a nucleus, irregular shape
-can reproduce by mitosis
-contain no hemoglobin-larger than RBC
-capable of their own movement outside blood stream
Origin:Formed in bone marrow and lymph nodes
Can live for many months or years
Number:There is approximately 1 white blood cell for every 600 red blood cells (makes up about 1%of the blood)
FUNCTION:
1.Part of body's defense system'
2. Fight infectionsand prevent disease by ingesting foreign cells or substances
3.Producing antibodies

DISEASES OF WHITE BLOOD CELLS:

-WBC's increase in number during fever or sickness
LEUKEMIA:(Cancer of the blood)Leukemia is cancer of the body's blood
-forming tissues, including the bone marrow and the lymphatic system.
Symptoms:'
i)first there is an increase in WBC's, then as the cancer progresses there is a decrease in WBC's
ii)body can not fight infections
iii)no tumors are evident
iv)interfers with both RBC and WBC functions
Cause: type of cancer of the leucocytes(genetic or environmental exposure)
Treatment:Controlled by drug therapy
MONONUCLEOSIS:is a contagious illness typically caused by a virus
Symptoms:
i)a high number of WBC's
ii)production of large number of WBC
iii)leads to fatigue, fever, sore throat, swollen glands
Cause: a virus, transmitted by saliva, occurs in young people
Treatment: None, antibodies must be produced by body itself.

PLATELETS / THROMBOCYTES

Appearance:
-not cells but tiny fragments of other cells
-each platelet is surrounded by a membrane and is filled with Thromboplastin
-irregular shape
-no nucleus
Origin:-made when small pieces of cytoplasm are pinched off the large cells which are found in bone marrow.
Number:-produced at the rate of 200 billion a day -live for average of 5-9days
FUNCTION:
1.Involved in blood clotting
2.Repair of damaged blood vessels

DISEASES OF PLATELETS:

HEMOPHILIA
Hemophilia
is a genetic disorder in which your blood doesn't clot normally because it lacks sufficient blood-clotting proteins (clotting factors).
Symptoms:
-normal blood clotting is not possible-occurs most often in males
Cause:
-sex linked inherited disease
-blood clotting agent is missing from the blood
Treatment:
-receive injections of missing factor from genetically engineered blood

STEPS OF BLOOD CLOTTING

STEP 1: INJURY/ DAMAGE TO BLOOD VESSELS
a cut on the skin or an internal injury creates a tear in the blood vessel wall, which causes blood flow
STEP 2: BLOOD VESSEL CONSTRICTION/VASCULAR SPASM
The blood will constrict the blood vessel called vasoconstriction to control blood loss
It will limit the blood flow to the damaged area
STEP 3: PLATELET PLUG
Platelets are activated and secrete chemicals to attract other cells to the area.
The platelets stick to one another and to the wound site to form a plug.
STEP 4: BLODD CLOTTING/ COAGULATION/ CLOT FORMATION
Platelets secret THROMBOPLASTIN, which converts PROTHROMBIN (inactive enzyme) and CALCIUM to form the active enzyme THROMBIN
Thrombin catalyzes the conversion of soluble FIBRINOGEN (GLOBULAR PLASMA PROTEIN) to insoluble FIBRIN (Fibrous protein)
The fiber in strands form a mesh of fibres around the platelet plug and trap erythrocytes and more platelets to form the clot/sticky plug

THE POTENTIAL DANGER OF BLOOD CLOTS IN DIFFERENT AREAS OF THE BODY IE. HEART, BRAIN

Blood clots that form in the body present potential danger for several reasons:
1.Stop the flow of blood to vital organs,and cause cells to die due to oxygen starvation
2.Decrease the flow of blood, and increase blood pressure (Embolismsare moving blood clots)
3.Blockage blood vessels may rupture and cause internal hemorrhaging and death (Aneurysm)

SECTION 2:BLOOD TYPES:

Human blood can be differentiated into four groups:
i) Blood type A
ii) Blood type B
iii) Blood type AB
iv) Blood type O
-blood types are determined by either the presence or absence of certain proteinsfound on the cell membranes of the red blood cells (antigens)and in the plasma part of the blood(antibodies) that cause AGGLUTINATION(clumping) of the red blood cells.
ANTIGENS:are substances, usually proteins that stimulatethe immune response and the formation of antibodies
Antigens are proteinsthat can be found on the erythrocytemembranes (RBC) ORmay be "proteins found on foreign particles" that enter the bodyTwo of these antigens on the RBC are classified antigen A and antigen B

ANTIBODIES:

are proteins formed within the blood that reactswith antigens The two antibodies that correspond to antigens A and B are designated anti-A and anti-B.Agglutination is due to the combination of an antigen and its compliment antibody.IE: blood cells with antigen A will clump in the presence of anti-A antibodies.

BLOOD TYPE ANTIGENS ANTIBODIES CHART

BLOOD TYPE ANTIGENS ANTIBODIES
TYPE A ANTIGEN A ANTIBODY B
TYPE B ANTIGEN B ANTIBODY A
TYPE AB BOTH A & B NEITHER A OR B
TYPE O NEITHER A OR B BOTH A & B

BLOOD TRANSFUSIONS:

o When large quantities of blood are transfused, the possible reaction of the donor's antigens with the recipient's antibodies must be considered
oIncorrect matching of blood could be fatal.Persons with type O- are considered to be universal donors,as they contain no antigens to cause recipient's antibodies to clump around "foreign antigens"Persons with type AB+ are universal recipients, as they contain all antigensso nothing is ever foreign and no antibodies to attack donor's antigens. Persons with type A cannot receive type B blood
▪as type A has antigen A and antibodies B,
▪antibodies B will attack "foreign antigen B"that is does not recognize, and cause clumping of the blood.Vise versa for type B.

Rh FACTOR

In addition to the ABO antigens, there isanother antigen on the red blood cellscalled the Rh antigen(named after the rhesus monkey in which the antigen was discovered)
•People who have the Rh antigenon their red blood cells are said to be Rh positive. (Rh+)
•People who do not have the Rh antigenon their red blood cells are said to be Rh negative (Rh-)

ERYTHROBLASTOLSIS FETALIS

Rh factor can cause complications in some pregnancies.Problem occur only if the mother is Rh-and she is carrying an Rh+baby.
FIRST PREGNANCY:At birth the Rh+baby's blood mixes with the Rh-blood of the mother. The mother's blood then makes anti-Rh+antibodies.
SECOND AND SUBSEQUENT PREGNANCIES:Should the mother become pregnant again, these antibodies will cross the placenta.If the new fetus is Rh+, the anti-Rh+antibodies from the mother will destroy red blood cells in the fetus, endangering the fetus.
TREATMENT:When the Rh+fetus is 28 weeks old, and again shortly after birth, the Rh-mother is given a substance that removes the Rh antibodies from her blood. As a result her fetus will no longer be in danger.

SECTION 3:IMMUNE SYSTEM:

The immune system is our primary defense against disease-causing micro-organisms or pathogens. Examples of pathogens are: viruses, certain bacteria, protozoans, and fungi.

ZOONOSIS

AP ATHOGENi s an agent that causes disease -either a microorganism (bacteria, protist, fungi or parasite), virus or prion
▪Pathogens are generally species-specific in that their capacity to cause disease (pathogenesis) is limited to a particular species]
▪Pathogens are usually highly specialized with a narrow range of hosts
▪There are viruses that are specific to birds, pigs, bacteria, humans
▪Polio, syphilis, measles and gonorrhea are examples of diseases caused by pathogens that specifically affect human hosts
▪Certain pathogens, may cross the species barrier and be able to infect and cause disease in a range of hosts
▪These diseases originate in one species and may transition to infect another species
▪More common for diseases resulting from bacteria and fungus to cross species barriers.
ZOONOTIC DISEASES (ORZOONOSES):Diseases from animals that can be transmitted to humans
▪Examples of zoonotic diseases include rabies (dogs), certain strains of influenza (e.g. bird flu) and the bubonic plague (rats), Lyme disease (deer ticks), West Nile virus (mosquito), SARS, Ebola, H1N1,HIV/AIDS, COVID-19
•Human diseases problematic in other species: Tuberculosis, salmonella, ringworm

THE IMMUNE SYSTEM CONSISTS OF

1.NONSPECIFIC DEFENSE
2.SPECIFIC DEFENCES against infection.
NONSPECIFIC: Not directed against a particular pathogen, rather guard against ALL infections regardless of their cause.
SPECIFIC:Attempts by the body to guard against particular pathogensthat have managed to get past body's nonspecific defenses.

FIRST LINE OF DEFENSE:

SKIN:
tough, flexible layerthat covers most of your body. Very few pathogens can penetrate the layers of dead cells at the skin's outer surface.
•OIL and SWEAT glands:at the surface of the skin produce an acidic environment that kills many pathogens
•MUCUS:
-Consists of a thin region of living surface cells that release fluids to wash away pathogens (eg. mucus, saliva, tears, etc.)-Contains biochemical defence agents(secretions contain LYSOZYME which can destroy cell walls and cause cell lysis of many bacteria)
-Mucous membranes may be ciliated to aid in the removal of pathogens
•Cilia HAIRS in the nose and throat trap and remove pathogens and push them back toward the mouth and then enter the stomach where they are destroyed by stomach acid and digestive enzymes.(or remove pathogens with physical actions such as coughing / sneezing)

SECOND LINE OF DEFENSE:

INFLAMMATORY RESPONSE:
The bacteria within a wound cause fluid and white blood cells to leak from blood vessels into nearby tissue. Bacteria are attacked by PHAGOCYTES, which engulf and destroy any and all bacteria. This is called NONSPECIFIC defence.The infected area is said to be inflamed, reddish, swollen and hot.Eventually PUS (mixture of dead cells, bacteria, and body fluid) collects in the wound and either drains or is absorbed by the body.
FEVER:Increase action of WBC and increase body temperature in response to an infection.Many disease causing micro-organisms cannotsurviveat a higher than normal temperature and growth of the micro-organism is slowed down or stopped

THIRD LINE OF DEFENSE:

IMMUNE RESPONSE: The key to the immune system isLYMPHOCYTES,a type of white body cell. The immune system recognizes, attacks, destroys, and remembers each kind of pathogen that enters the body.The immune system discriminatesbetween different kinds of pathogens.This is called SPECIFICdefense. RECALL: antigen is any substance that causes an immune response. Most antigens are proteins, but can be carbohydrates, and nucleic acids and are displaced on the outer surface of pathogens.

ANTIBODY IMMUNITY:

is a type of chemical warfare within your body that involves B-CELLS or B-LYMPHOTCYTES to produce ANTIBODIES. RECALL: Antibodies are special proteins that bind to the antigen on the surfaces of the pathogen and help destroy it.Antibodies are shaped like the letter Y and have two identical antigen binding sites that fit the shape of a particular antigen. Although each B-cell produces only one type of antibody, the body's population of B-cells can produce hundreds of thousands of different antibodies.

ANTIBODY PRODUCTION

ANTIBODY PRODUCTION:
1.Pathogen enters body tissue (BACTERIA or VIRUS)
2.It is attacked by macrophages at the infection site. Antigens of the pathogen are displayed on the surface of the macrophage.
3.HELPER T CELLSidentify foreign invading substances by their receptor sites that recognize and bind to the antigens on the macrophage. They stimulate other cells to fight infection.
4.B-CELLS are activated and grow and divide rapidly producing a large number of specialized B-cells called PLASMA CELLS
5.PLASMA CELLS produce ANTIBODIESthat bind to the antigens on the infected cells. Antibodies attach to the antigen and form an antibody-antigen complex that is engulfed by phagocytes.
6.Plasma cells also produce MEMORY B CELLSthat retaininformation about the geometry of the antigen, and remain in the blood to respond to future invasions by the same pathogen.Provide long-term immunity.
7.SUPPRESSOR T CELLS release substances that slow down and eventually stop the production of antibodies from plasma cells. "Turn off immune system"

PRIMARY IMMUNE RESPONSE:

The production ofantibodies from the first exposure to an antigen
-First 5 days after exposure to antigen, NO measurable amount of antibodies.
-Next 10-15 daysbody builds up antibodies against antigen

SECONDARY IMMUNE RESPONSE:

Once the body has been exposed to a disease a large group of B-cells and T-cells remains capable of producing antibodies should the pathogen reappear in the body.
-The secondary immune response is more powerful than primary response and the disease never gets a chance to develop.
-Within 1-2 dayshigh levels of antibodies are produced

ACTIVE IMMUNITY: (production of antibodies)

Type of innate immunity produced by the body when stimulated by exposure to a pathogen or by a vaccine that results in the production of antibodies.

PASSIVE IMMUNITY:(borrowed immunity)

Type of borrowed immunity that results when antibodies produced by other animals against a pathogen are injected into the bloodstreamor transferred in breast milk-passive immunity is short lived because the body destroys borrowed antibodies, but it is fast acting

WHAT DO ANTIBODIES DO?

1.Immobilizeantigen
2. Stop antigens from moving so they may be engulfed by phagocytes
3. Break down the pathogen's cell wall to destroy it
4. Attach to antigen on pathogen to attract WBC's

VACCINATIONS:

FUNCTION: Vaccinations induce long-term immunity to specific pathogenic infections by stimulating the production of memory cells
WHAT IS A VACCINATION:
▪A vaccine is a weakened or dead form of the pathogen that contains antigens but is incapable of triggering disease
▪The body responds to an injected vaccine by initiating a primary immune response, which results in memory cells being made
▪When exposed to the actual pathogen, the memory cells trigger a more effective secondary immune response The length of time a person is immune to infection following a vaccination depends on how long the memory cells survive.
▪Memory cells may not survive a lifetime and individuals may subsequently require a booster shot to maintain immunity

HERD IMMUNITY

Vaccinations programs are implemented to reduce the outbreak of particular infectious diseases within populations
▪An epidemicis a substantially increased occurrence of a particular infection within a given region
▪A pandemicis an epidemic that has spread across a largegeographical area(like a continent)Vaccination confers immunity to vaccinated individuals but also indirectly protects non-vaccinated individuals immunity
▪HERD IMMUNITY IS when individuals who are not immune to a pathogen are protected from exposure by the large amounts of immune individuals within the community

SMALL POX

Smallpox was the first infectious disease of humans to have been eradicated via vaccination
▪When a disease stops circulating in a region it is consideredeliminated-if it is eliminated worldwide, it is considerederadicatedSmallpox was targeted for eradication in 1967 by the World Health Organization (WHO), via a global vaccination program
▪The last known case of smallpox in a civilian was registered in 1977 and it was officially declared eradicated by WHO in 1980The eradication of smallpox by vaccination was successful for a number of reasons:
▪Smallpox was easily identifiable due to overt clinical symptoms, which helped to limit potential transmission
▪Transmission only occurred via direct contact and there were no human hostsor reservoirs to sustain the infectious agent
▪The infection period was short lived (3 -4 weeks) and the virus was stable anddidn't mutate into alternate strains
▪There was global cooperation and immunity was long-term so repeated booster shots were unnecessary

What is a vaccination

4 types of vaccine development in use:
conventional method:
whole virus
Protein submit
nucleic (RNA/DNA):
eg covid-19
Viral vector