Pathophysiology exam 1: Inflammation

What is inflammation in response to?

Cell injury (tissue irritation) or death

What is the result of inflammation?

• Minimizes effects if infection or injury

• Removes damaged tissue

• Generates new tissue

"-itis”

inflammatory response

Inflammation is caused by…

• Inflammatory mediators

• Fluid movement and leukocytes migration to extravascular tissues

What are the 3 types of cells of inflammation?

• Endothelial cells

• Platelets

• Leukocytes

Roles of endothelial cells in inflammation

• Selective barrier to microbes and inflammatory stimuli via tight junctions

• Regulate immune cell proliferation

• Repair process

What do the tight junctions between endothelial cells regulate and release?

• Leukocyte extravasation (leak out of BV)

• Release inflammatory mediators (i.e., cytokines like IL-8)

What type of leukocyte is the 1st to appear in the inflammatory response?

Neutrophils

• present at injury site after about 90 minutes

What leukocytes are there? Which are granulocytes and which are agranulocytes?

Granulocytes:

• Neutrophils

• Eosinophils

• Basophils —> Mast cells

Agranulocytes

• Monocytes/macrophages

• Lymphocytes

Neutrophil function

• Phagocyte

• Attack bacteria

• (short lifespan so they must be regenerated by BM often)

Eosinophil function

• Phagocyte

• Protect against parasites

• A response in allergic reactions

• (longer life span — seen in chronic inflammation)

Basophil function

• Release histamines during allergic reactions

When do mast cells form?

When a basophil leaves BV circulation and goes into the tissue “tracts” to find the invader and destroy it

Monocyte function

• Phagocyte

• Produce vasoactive mediators

• once they leave the blood stream and go into the tissues, they turn into macrophages

***Macrophage function

***Phagocytes that are part of the innate to the inflammatory process

• Antigen presenting cells

What are mediators of inflammation?

When released, they tell other cells what to do

Where do mediators of inflammation come from?

They are a result of acute inflammation and they come from either the liver (plasma-derived mediators) or surrounding cells (cell-derived mediators)

What two cellular mediators of inflammation are released? Where do they come from?

• Histamine — mast cells

• Serotonin — platelets

• Leukotrienes

• Prostaglandins

When are cellular mediators of inflammation released?

Released in acute inflammatory response

Role of histamine and serotonin release

Dilate BVs and increase permeability of BVs

Process of microorganism movement

1. Histamine/serotonin released

2. BVs contract initially

3. BVs relax

4. gap btwn endothelial cells

5. plasma leaks out

6. helps move microorganisms

Role of leukotrienes and prostaglandin cellular mediators

• Potentiate (make more powerful) the effect of histamine and serotonin

  • more vasodilation and increased permeability

Cytokine

• Is a cellular mediator of inflammation involved in acute inflammation

• Intracellular signaling proteins that regulate inflammatory responses by facilitating communication between cells

What type of inflammation is cytokines involved in?

Acute

Types of cytokines (3)

• Interleukins (IL-1)

• Tumor necrosis factor alpha (TNF-a)

• Chemokines

Process of acute inflammation

1. Bacteria enters body which has an antigen on the surface

2. T-cells are made aware of the bacteria via the antigen

3. Cytokine is released, stimulating the macrophage

4. Macrophage releases TNF-a and IL-1 cytokines

5. The cytokines signal for endothelial cells, neutrophils, and acute-phase response to activate

6. Now you feel sick

What is acute inflammation triggered by?

Tissue injury or infection

What is acute inflammation characterized by?

• Plasma leaking out from BVs to tissues to aid in detoxifying cells

• Emigration of leukocytes, signaling for other immune cells to come help

What are the most common signs of acute inflammation?

• Redness

• Swelling

• Heat

• Pain

• Loss of function (i.e. Crohn’s disease = can’t absorb nutrients)

Systemic (affects whole body) signs of acute inflammation (when it gets really bad)

• Fever

• Leukocytosis

• May see an increase in ESR and CRP (proteins that can be secreted from the liver)

Process of acute inflammation

Purpose of vascular phase

Bring more blood flow

Steps of vascular phase

1. Brief vasoconstriction in response to injury

2. Vasodilation — caused by histamine and NO, resulting in warmness and redness

3. Increased permeability