Immunity

Question 1

Immunity:
system of biological structures and processes within an organism that protects against diseas
Components:

Answer 1

Innate Immune system [less specific]
Adaptive Immune system [more specific}
- Humoral [ Bcell}
- Cell-mediated [T cell]

Question 2

B Cell

Answer 2

also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system by secreting antibodies
Produced in Bone Marrow

Question 3

T Cell

Answer 3

T lymphocyte is a type of lymphocyte (a subtype of white blood cell) that plays a central role in cell-mediated immunity. T cells can be distinguished from other lymphocytes, such as B cells and natural killer cells, by the presence of a T-cell receptor on the cell surface.
Produced in Thymus

Question 4

Resistance vs Immunity

Answer 4

Immunity = defense mechanism against foreign structures
Resistance = natural ability to resist micro-organisms [incl passive, active + artificial immunity]

Question 5

Innate vs Adaptive Immune system

Answer 5

If physical barrier is breached = innate system provides immediate non-specific response
If innate response is not adequate = adaptive is activated by innate system
The improved response is retained after pathogen elimination = Memory response

Question 6

Antigens

Answer 6

Substances that provokes a specific immune response
Protein or large carbohydrates molecules usually part of infectious agents [bacteria]
Antibodies are produced during immune response binding to antigen
Thymus-dependent or -independent
-dependent= T cell participation
-independent= B lymphocytes

Question 7

Antibodies

Answer 7

proteins produced during immune response binding to antigen [antigen binding sites]
All antibodies belong to immunoglobulin class of proteins produced by plasma cells

Question 8

Immune reaction

Answer 8

Antigen binds with antibody + forms Ag/Ab complex resulting in:

• Precipitation [soluble antigen is rendered insoluble]
• Agglutination [particulate antigen is aggregate same as precipitation]
• Cross-reactivity [antibodies elicited by one antigen can cross react with an unrelated antigen - similar epitope]
• Enhancement of natural non-specific immune

Question 9

opsonization

Answer 9

refers to an immune process where particles such as bacteria are targeted for destruction by an immune cell known as a phagocyte . The process of opsonization is a means of identifying the invading particle to the phagocyte.

Question 10

Complement system

Answer 10

Consists of 9 main protein components present and inactive in blood
3 pathways of compliment activation
Activation results in formation of multi-molecular enzymes that activate further components in cascade
Ultimately generating a membrane attacking complex capable of cell lysis

Question 11

Upset to complement system

Answer 11

Upset results in humoral + cell mediated immune to become the source of disease:
1 - Hypersensitivity reactions
2 - Immune deficiency
3 - Autoimmune disease

Question 12

Hypersensitivity reactions

Answer 12

Inappropriate response to an antigen following previous exposure - differ from protective response in that it is exaggerated and cause damage to host
Type 1-3 = Humoral antibodies
Type 4 = Cellular antibodies

Question 13

Type 1 Hypersensitivity

Answer 13

Anaphylaxis, Atopy + Allergy
IgE mediated
Immediate type hypersensitivity
Degranulation of IgE sensitized mast cells + basophils leads to Hypotension, bronchoconstriction and collapse - anaphylaxis

Question 14

Atopy

Answer 14

Overproduction of IgE to common environmental antigens
Anti-histamine = blocks H1 receptor
Mast Cell stabilizer = prophylactic

Question 15

Type 2 Hypersensitivity

Answer 15

IgG mediated Cytotoxic reaction
Increased opsonization (phagocytic)
antibodies produced by the immune response bind to antigens on own cell surfaces
eg. myasthenia gravis, goodpastures, Guillain–Barré syndrome + Graves’ disease

Question 16

Type 3 Hypersensistivity

Answer 16

Immune Complex - IgE + IgM driven
Ag-Ab complex in various tissue induces compliment activation with inflamm resulting in massive neutrophil infiltration
eg. SLE + RA

Question 17

Type 4 Hypersensistivity

Answer 17

Delayed type or Cell mediated
Tissue damage independently of antibody presence
eg. DM, GC arteritis + MS (auto-immune)

Question 18

Immune defieciencies

Answer 18

Primary - B or T cells or both (inherited)
B Cell - infection of pyogenic bacteria
T Cell - viral & fungal infections
Seconday - T Cells affected, later B cell deficit occurs

Question 19

Pyogenic Bacteria

Answer 19

suppurative or purulent bacterium

Question 20

Graves’ Disease

Answer 20

Excessive amts of Thyroid hormone produced
TSI combines with IgG and mimicks TSH + produces thyroxine (T4) + triiodothyronine (T3)
Dx = low TSH with high T3 + T4
anxiety
exophthalmos
chest pain
insomnia
hypertension
fatigue
increased sweating
muscle weakness
sensitivity to heat

Question 21

TSI vs TSH

Answer 21

Thyroid stimulating immunoglobulin

Thyroid stimulating Hormone (increases metabolism

Question 22

Myasthenia Gravis

Answer 22

a rare chronic autoimmune disease marked by muscular weakness without atrophy, and caused by a defect in the action of acetylcholine at neuromuscular junctions
Hallmarks = muscle weakness + fatique

Question 23

ACh

Answer 23

AcetylCHoline
neurotransmitter in the ANS
internal transmitter for the sympathetic nervous system
final product released by the parasympathetic nervous system