Lecture 2: Inflammation

Inflammation

A localized, non-specific response triggered when tissues are injured or foreign material is identified in the body.

Mast Cells

Cells that initiate the acute inflammatory response by releasing inflammatory chemicals such as histamine. They are derived from the same stem cells as basophils and are typically located at the site where a pathogen enters the body.

What are leukotrienes? what are they made up of ?

Inflammatory chemicals produced from phospholipids that have similar vascular effects as histamine but act slower and have a prolonged effect.

Define Degranulation:

The emptying of pre-formed granules containing histamine and chemotactic factors from mast cells to the extracellular matrix.

Neutrophils

Phagocytes that are the first to show up at the site of injury during acute inflammation. They are the most abundant white blood cells and play a crucial role in the acute inflammatory response.

Eosinophils

White blood cells that are important for parasitic inflammation. They are involved in the chemotaxis response and help clean up the area by eating up dead cells and debris.

Monocytes/Macrophages

White blood cells that travel as monocytes and become macrophages in the tissue. They arrive later than neutrophils and play a similar role in the acute inflammatory response.

What is the fxn of Leukotrienes during the inflammatory process?

They increase vascular permeability and induce blood vessel dilation, as well as promote neutrophil and eosinophil chemotaxis.

What is the fxn of Prostaglandins during the inflammatory response?

Inflammatory chemicals derived from phospholipids that have prolonged "histamine-like" effects. They induce PAIN, increase vascular permeability, and induce blood vessel dilation.

What is the process of Platelet Activation Factor (PAF) during the inflammatory process?

An inflammatory chemical produced mainly by mast cells that has similar effects to histamine but with an emphasis on activating platelets for blood clotting.

Cardinal Signs of Inflammation (PRISH)

pain, redness, impaired function, swelling (edema), and heat. These signs are localized to the site of inflammation.

Fever

A systemic manifestation of inflammation characterized by an increase in body temperature. It is usually accompanied by malaise, fatigue, and anemia.

Chronic Inflammation

Inflammation caused by a relatively milder, more persistent stress or injury.

What are the lines of defense? Specify which lines of defense are innate.

Physical barriers & Secretion, Inflammatory Response, and Adaptive immune response. The first 2 lines are innate. Adaptive response is a learned response

Define Adaptive Immune response:

highly specific, systemic rxn typically in response to an antibody-antigen association

Which cells initiate the acute inflammatory response?

Mast cells

Mast cells responds to cell injury, in order to

remove caus, remove damaged tissue, initiate tissue repair

How long does the acute inflammatory process take?

seconds and may last to 8-10 daya

Mast cells are like guard dogs because _____

Recognize foreign particles and make a chemical noise

Mast cells are derived from the same stem cells as basophils. Name them.

Neutrophils, Leukocytes, Monocytes,Eosinophils, basophils

Where are mast cells located?

Near skin surfaces, Mucous membrane, Around blood vessels

Once the process of degranulation starts, histamine releases causing 3 reactions which are…

blood vessel dilation, capillary endothelial retraction, and mucous production

Pre-formed biochemical mediators that work immediately during degranulation are…

histamine, WBC chemotactic factor, and other cytokines

Describe blood vessel dilation:

increases blood flow to area = more cell and protein to area » causes redness and warmth

Describe endothelial retraction:

Leads to space forming between the cells > allows cells and proteins to enter tissue (exudation)

Purpose of mucous production (3rd response to histamine release)?

Traps foreign objects and release chemotactic factors

What is the Greek breakdown of chemotaxis?

“chemo” = chemical and “taxis” = mvmt

Which stem cells are attracted during chemotaxis?

Attracts NEUTROPHILS and EOSINOPHILS to the site of injury towards area of higher concentration of signal » leaves a bread crumb trail

Which stem cells first appears during acute inflammation response?

NEUTROPHILS are first PHAGOCYTES to show up to the area >> v important for acute inflammation

Which cells are most abundant during the acute cell response? How long is a life span?

Neutrophils; 10 hours (removed as pus)

Eosinophils are important for what type of inflammation

PARASATIC inflammation

When do monocytes/macrophages arrive during the acute immune response?

2-7 days

State the 3 main plasma protein proenzyme systems that are activated from mast cells?

Complement system, clotting system, and kinin system

What are the 3 fxns of the complement system?

1. OPSONIZATION - “Tags” bacterial capsules with proteins and renders it susceptible to phagocytosis

2. Act as anaphylatoxin >> Causes degranulation of mast cells and increases inflammatory respons

3. Cause direct death of pathogen >> Acts as membrane attack complex and perforates bacterial cell membrane

Describe the fxn and process of the clotting system?

1. Prevents spread of infection and stops bleeding

2. Activating fibrinogen causes the production of FIBRIN that forms insoluble clot

What are the 3 main fxns of the kinin system? Which chemical mediator is primarily involved?

Bradykinin:

1. Induces pain (along with ProstaGlandins)

2. Promotes leukocyte chemotaxis

3. Prolonged phase of inflammation with histamine-like effects: dilates blood vessels and increases vascular permeability

Define margination (pavementing)

WBC sticks to the endothelial cells lining the blood vessels

Define Diapedesis (exudation):

Move between retracted endothelial cells

What are the systemic manifestations of heat during an acute inflammatory process?

• Fever: usually accompanied by malaise, fatigue, anemia

• Leukocytosis: primarily of leukocytes

• Increased plasma proteins

• Muscle catabolism

What cause chronic inflammation?

relatively milder, more persistent stress or injury

What is the duration of chronic inflammation?

2 weeks or longer

what are the characteristics of chronic inflammation?

• Less hyperemia, less edema

• Primarily lymphocytes and macrophages

• More fibrosis, less exudate

• Could have granuloma formation (walled off site with fibrous deposits)

Which WBC is primarily found during chronic inflammation?

Macrophages

Which WBC is found primarily in the adaptive immune response?

Leukocytes