Immunology- Intoduction to non-specific immunity

Question 1

What are the functions of the lymphatic system?

Answer 1

Draining excess intistial fluid (extracellular fluid) from the tissue spaces.
Transport of lipids and lipid soluble vitamins around the body.
Defence of diseases and immunity.

Question 2

How is the lymph formed?

Answer 2

The lymph is formed from the blood plasma that filters from the blood capillaries into the intistial space.
Excess intistial fluid passes through the endothelium init the lymphatic vessels and enters the lymphatic capillaries.
The fluid resembles blood plasma but without the larger proteins and RBCs.

Question 3

Define the two classes of groups lymphatic tissue and organs are classified in?

Answer 3

1. Primary lymphatic organs- They provide and environment where mature WBCs such as B and T cells can mature and develop. Including the red bone marrow and the thymus gland.
2. Secondary lymphatic organs and tissues- includes the lymph nodes, the spleen, the lymphatic nodules. It is within the secondary lymphatic structures that the majority of the immune response occurs.

Question 4

What cells are consisted in the medulla?

Answer 4

B-cells
plasma cells
macrophages

Question 5

What is contained din the inner cortex?

Answer 5

t- cells

dendritic cells

Question 6

What are the following pathogenic organisms that can induce an immune response?

Answer 6

Virus
Fungi
Bacteria
Protozoa
Helminths

Question 7

Define and Explain the difference between innate non specific immunity vs. Adaptive specific immunity?

Answer 7

Innate Immunity

• Recognises molecules which are commonly associated with pathogens.
• Represents the most ancient form of immunity and is present in the form in all animals.
• You are born with innate immunity
• Allows fast immediate response in the presence of a pathogen. As its the first line of defence.
• The response is identical each time.

Adaptive Immunity

• Specific to an antigen
• Only found in vertebrates
• Acquired my experience
• On first exposure to a pathogen it takes a number of days to respond but are in greater aptitude and more rapid.
• They then form memory cells

Question 8

Why do we have a non specific immune response?

Answer 8

A mechanism that protects the body from foreign pathogens in a non specific way. As it allows prevention of pathogens entering the body and the destruction of foreign materials once they have entered the body.

Question 9

What are the 3 non specific defences?

Answer 9

1. Antimicrobial proteins
2. Inflammation
3. Natural Killer Cells and phagocytosis

Question 10

What are derived from the common lymphoid progenitor?

Answer 10

• B cells which go on to form plasma cells
• T cells which become activated T cells
• Natural killer cells become activated natural killer cells.

Question 11

What is derived from the common myeloid progenitor?

Answer 11

In the bone marrow you have the erythrocytes and megakaryocytic.
But they also form granulocytes which consists of:
- Neutrophils
-Basophils
-Eosinophils
-Unknown precursor mast cell
-Monocyte.

Question 12

What are the 3 different antimicrobial proteins?

Answer 12

1. interferons
2. Compliments
3. Transferins

Question 13

Define the role of interferons?

Answer 13

Interferons (IFNs) are produced by lymphocytes, macrophages, fibroblasts that have been infected by a virus.
They act as chemical messengers causing the neighbouring cells to produce antiviral proteins that interfere with the viral replication.

Question 14

What are the three different types interferons?

Answer 14

Alpha
Beta
Gamma

Question 15

Define the role of compliments?

Answer 15

A protein that is normally found in its inactive state in the blood plasma on the plasma membrane where it forms the compliment system.
When this is created it enhances the inflammatory reactions.

Question 16

Define the role of transferins?

Answer 16

Transferins are iron binding proteins that inhibit the growth of certain bacteria by reducing available iron.

Question 17

What are the role of natural killer cells?

Answer 17

Specialised granular lymphocytes.
They are crucial for the defence of tumours and virally infected cells.
they don’t recognise pathogens directly they detect the affect of a pathogen on the host cell.
It can either detect the lack of host proteins or induction of stress proteins.
Nk cells attack the MHC complex antigens.

Question 18

How do Natural killer cells destroy their targets?

Answer 18

By releasing perforins or by binding and inflicting damage directly.

Question 19

Define neutrophils?

Answer 19

They are short lived
Migrates during inflammation
Produces a mast of antimicrobial factors.

Question 20

Define dendritic cells?

Answer 20

Found throughout the body

Crucial link between innate and adaptive immune response.

Question 21

Define macrophages?

Answer 21

Found in most but not all tissues.
Highly phagocytic and anti microbial.
Directs both innate and adaptive immunity through recreation of cytokines and antigen presentation.
Important from non-inflammatory clearance of apoptic cells.

Question 22

Explain the role of inflammation in the body?

Answer 22

Describes the defence response to damage or infection associated with symptoms of redness pain.

Question 23

What is the function of the inflammatory response?

Answer 23

Traps invading microorganisms and allows the region to perfused with phagocytes and natural killer rich tissue fluid.

Question 24

Is the inflammatory response adaptive or non specific explain why?

Answer 24

The process is non specific as it will follow the same pathway regardless what the source of damage is so, a burn will initiate the same inflammatory responses as a cut.

Question 25

What are the 3 major phases of the inflammatory response?

Answer 25

1. Vasodilation
2. Increase permeability of blood vessels
3. Phagocyte migration and tissue repair.

Question 26

What other components is the inflammatory response aided by?

Answer 26

Histamines
leukotriens
Complements 
kinins 
prostaglandins

Question 27

Define the role of histamines?

Answer 27

Released by mast cells in connective tissue and by basophils, platelets in response to injury.
Histamines attract neutrophils and macrophages to the injury and also induces vasodilation and increase permeability of blood vessels.

Question 28

Explain the role of kinins?

Answer 28

formed from the inactive precursor molecules called the kininogens and induces vasodilation and increases permeability to blood and promotes chemotaxis by phagocytes.

Question 29

Define prostaglandins?

Answer 29

They are lipids which are released by damaged cells. They intensify the effects of histamines and the kinins. And allows the migration of phagocytes through the capillary walls.

Question 30

Define leukotriene?

Answer 30

They act as a guide for phagocytes and increase blood vessels and adherence of phagocytes to pathogens.
They are released by basophils and mast cells

Question 31

Define complements within the inflammatory response?

Answer 31

They consists of a number of components that are associated with the release of histamines, promotion of phagocytes and Allows direct destruction of bacteria.

Question 32

What is the first factors that occurs following and injury?

Answer 32

Arteries dilate and become more permeable which results in localised edema and increase in temperature which is associated with pain.

Question 33

How is a scab formed?

Answer 33

Leakage of blood clotting factors into the injury results in the formation of a scab.

Question 34

Explain the process of diapedesis?

Answer 34

When within the hour of migration of injury the neutrophils and monocytes are attracted to the wound site. These cells migrate from the blood stream into the tissue.

Question 35

Which cells are first into the wound site after an injury?

Answer 35

The neutrophils are normally the first into the wound site which is then followed by the monocytes a few hours later. These then transform into wondering phagocytic macrophages where they eventually form pus.

Question 36

Why does the formation of pus occur?

Answer 36

It forms until the infection has been destroyed. And then it is either drained or absorbed.

Question 37

What happens when the pus is not able to be absorbed or drained away?

Answer 37

It results in the formation of an abscess or an ulcer.

Question 38

Define ulceration?

Answer 38

Feature common in the extremities of individuals with poor blood circulation such as diabetics.

Question 39

How does a fever occur?

Answer 39

An increase body temperature due to an inflammatory response. And it arises due to many bacterial toxins which can elevate body temperature by stimulating the release of cytokines and interleukins.

Question 40

What changes occur in the body during a fever when bacterial toxins stimulate the release of cytokines and intrleukins?

Answer 40

Results in hypothalmic thermoregulatory set point being elevated which causes an increase in temp and enhance the activity of interferons and increase the activity of macrophages whilst inhibiting the replication of bacterial cells.

Question 41

What are the functions of a macrophage?

Answer 41

Role in homeostasis
Roel in tissue remodelling
Macrophages ingest and process foreign material such as dead cells and debris.

Question 42

What are professional phagocytes?

Answer 42

They express a multitude of receipts on the surfaces that detect signals that are not normally present in healthy tissues.

Question 43

What are the 3 different types of proffesional phagocytes?

Answer 43

Scavneger receptors- for recognition of apoptosis and nercronic cells

Toll like receptors for recognition of pathogens.

Pattern recognition receptors which detect non self or damage.

Question 44

Define the classically activated macrophages M1 ?

Answer 44

they defend against bacteria, protozoa and viruses

anti tumour activity

Question 45

Define alternatively activated macrophages= M2

Answer 45

Anti inflammatory action

Regulate wound healing

Question 46

Define regualatory macrophages?

Answer 46

Secrete large amounts of iL-10

Question 47

What are myeloid derived suppresser cells?

Answer 47

Suppress anti-tumour immunity.