Introduction to immunology Flashcards
1st line of defense
- non specific
- skin, mucous membrane, chemicals
2nd line of defense
- non specific
- phagocytosis, inteferon, inflammation, complement, fever
3rd line of defense
- specific
- lymphocytes, antibodies
Neutrophils
phagocytosis and resolve inflammation
Eosinophils
destroy multicellular parasites and participate in hypersensitivity reactions
Basophils
release histamine and other chemicals involved in inflammation
monocytes
recognition cells in the IR and mediate all aspects of these responses
B cells
- antibody mediated IR and bind antigens to the B cell’s plasma membrane receptors IgG
- During activation are transformed to plasma cells which release antibodies
- Present antigen to T helper cells
NK cells
bind directly and non specifically to viral infected and cancer cells and directly kill them
Cytotoxic T cells
Bind to the plasma membrane of viral infected/ cancer cells/ tissue transplant and directly kill them
Helper cells
secrete cytokines and activate CTL, B cells, NK cells and macrophages
Macrophages
- Phagocytosis
- Extracellular killing via release of toxic chemicals
- Process and present antigen to T helper cells
- Secrete cytokines involved in inflammation, activation, and differentiation of T helper cells and systemic responses to infection
Monocyte
same
5 types of WBC and list them according to abundance
- Neutrophils
- Lymphocytes
- Monocytes
- Eosinophils
- Basophils
Hct
percentage of blood volume that is composed of RBCs
Three anticoagulants
- EDTA - determination of complete blood counts - contains potassium
- Sodium heparin -plasma determination in chemistry
- ACD - contains sodium polyanethol sulfonate - HLA phenotyping, parental testing, blood bank
Immunoglobins
- IgG – Main antibody in blood, provides long-term immunity.
- IgA – Found in mucosal areas (gut, lungs, saliva), protects against pathogens.
- IgM – First antibody in infections, strong activator of complement.
- IgE – Involved in allergies and parasite defense.
- IgD – Role in B cell activation, function not well understood.
Platelets morphology
biconcvex
Function of platelets
Haemostasis through adhesion, aggregration and activation
Thrombocytopoenia
results from low platelet coundnt. Lack of calcium, vitamin K and fibrinogen.
RBC morphology
- biconcave. Flexible membrane to allow deformation into any shape
- 7.8 d. 2 t. 1 c
Life span of RBC
120, they cannot repair themselves due to lack of nucleus, ER and mtd
Function of RBC
transport of Hb which carry oxygen from the lungs to the tissues and carbondioxide from the tissues to the lungs
Origin of RBC
synthesized in the bone marrow through erythropoesis
Anemia
a decrease in the O2 carrying capacity of blood
8 RBC abnormalities
- Dietary anemia = vit b12 deficiency and iron deficiency
- Haemorrhagic
- Megaloblastic
- Haemolytic
- Aplastic
- Renal
- Hypoxia
- Polycythemia
function of iron and vitb12
- iron - it is part of the HB which binds oxygen and if it is not there oxygen cannot bind and isnt carried to the tissues (decreases o2carrying capacity)
-vit b12 - involved in the DNA process of erythropoesis. RBCs will be abnormal and will not carry Hb
4 WBC abnormalities
- Leukocytosis - increase in WBC count
- Leukopoenia - decrease in WBC count - impairs immune response to infection
- Leukaemia - type of blood cancer that affects the blood and bone marrow
- Agranulocytosis - severe reduction of granulocytes
Role of neutrophils during inflammation
- move out of blood through endothelium capillaries and venules to inflamed areas
- margination - they tether to the endothelial cells by adhesion molecules, rolling along the vessels
- diapedesis - squeeze through the endothelial wall to the interstitial fluid and migrate to the site of tissue damage(chemotaxis)
= once at the site = phagocytosis
2 functions of cytokines
chemoattractants and mediate migration of neutrophils
Neutrophils (4)
- 60-70% of WBC, MULTI LOBED
- inflammation
- 6 hours in organs and 4-5 in tissue
- after injury the life span is shortened to a few hours bc then they die after performing their function
Eosinophils (4)
- 1-5% of wbc, bilobed
- first line of defense against parasitic infections
- do not engulf, attach to parasite by special surface molecules and release hydrolytic ezye=mes and highly reactive forms of oxygen that kill many parasites
- modulate allergic reactions like asthma
where are mast cells more abundant, and their life span?
in the skin and GIT
- long, they are present only in pathological condiditons
basophils distribution and life span
- blood, bone marrow
- short. 1-2 days
what makes basophils and mast cells able to erform their function?
the basophilic granules in their cytoplasm
complement (3)
- a group of 30 proteins that work by attacking microbes directly WITHOUT prior phagocytosis.
- circulate in the blood in thier inactive form and then activated by an infection or damage. One complement protein activate the other leading to a cascade of steps that activate the complement system and lysis the membrane
- 5 cp form the MAC which forms pores on the microbs PM causing it to leak. water and salt enter and kill the microbe
inteferons
- provide an innate defense against viral infections in a host cell
- produced by cells in response to an infection. and they bind to plasma receptrs on secreting cells and others whether infected or not
are inteferons specific or non
non
NK cells
- mediate ADCC
- play a role in early host defense and control viral replication
- kill target cells by binding to and releasing toxic substances similar to those released by cytotoxic T cells
