Understanding the Body's
Response to Infections - Prof.
MibelLatest 2025/2026 Exams
of Health, psychology|Graded
A+|Reliable A+ Certified Pass
Systems
- lymphatic, blood, interaction of immune organs
Organs
- lymph nodes, spleen, bone marrow, thymus
Cells
- macrophages, eonsinphil, B cell, NK cell etc.
Molecules
- antibodies, complements, cytokines, chemokines - ANSWERS-What does the
immune system consist of?
,Complement - system of soluble proteins
Cytokines - immune messenger hormones
Chemokines - cytokines which specialise in making cells move
Antibodies - secreted molecules which bind pathogens - ANSWERS-Describe the
molecules of the immune system
Leukocytes - all immune cells (innate and adaptive), white blood cells
Innate cells - macrophages, dendritic cells, neutrophils, eonsiniphils, basophils
and mast cells
Adaptive cells - lymphocytes (B and T cells) - ANSWERS-Describe the cells of the
immune system
Required for drainage of the periphery, collects everything in the periphery. The
lymphatics drain into the blood via the thoracic duct.
Scans for anything dangerous in the body.
,Lymph nodes are highly organised accumulations of immune cells at lymphatic
junctions. Swelling during infection is called lymphadenopathy - ANSWERS-
Describe lymphatics
Primary
- where immune cells are made, bone marrow and thymus.
- Immune cells are made in the bone marrow, T cells mature in the thymus.
Secondary
- Where immune responses are initiated and where T and B cells live most of the
time
- Includes the lymph nodes and spleen
- B cells reside inside lymphoid follicles, T cells reside around the follicles -
ANSWERS-Describe primary and secondary lymphoid organs
Physical
- skin, gut epithelium
Chemical
- low pH of skin, vagina and stomach
Flushing
- Tears, sweat, mucus
, Antimicrobial peptides
- present in many secretions
Competitive
- commensal bacteria out-compete dangerous bacteria in the gut - ANSWERS-
Describe barriers to pathogens
Cells that have been infected with a virus can release Interferon - IFNα and IFNβ
These induce an antiviral state in neighbouring cells
- Upregulation of antiviral proteins and antigen presentation
- Downregulation of everything else by degrading mRNA and inhibiting protein
translation factors (suppressing viral proliferation)
Synthetic IFNα is highly effective in Hepatitis B infections - ANSWERS-Describe the
antiviral state that some cells exhibit
Pros
- protects against infection and gives immunity to infection
- Kills mutated/tumor cells
Cons