Exam #1: Chronic Inflammation Flashcards
(40 cards)
What is chronic inflammation?
Inflammation that occurs for greater than 2 weeks
What is the most common presentation of chronic inflammation?
Insidious low-grade smoldering response without signs of acute inflammation
What are the causes of chronic inflammation?
1) Persistent microbial infections
2) Immune related inflammatory disease
3) Prolonged exposure to potentially toxic agents
List the general characteristics/ morphology of chronic inflammmation.
- Infiltration with mononuclear cells (macrophages, lymphocytes, & plasma cells) vs. neutrophils
- Tissue destruction induced by persistent stimulus or by inflammatory cells
- Attempts at healing–>connective tissue replacement of damaged tissue, angiogenesis, & fibrosis
Describe the histological characteristics of chronic pancreatitis.
Remember if you see islets & ducts= pancreas
- Inflammatory cells i.e. mononuclear cells
- Fibrosis= pink substance= collagen deposition
- Residual ductal structures with fibrosis
*No acinar tissue remaining
Describe the histological characteristics of chronic lung disease.
Note that the spaces without cartilage= alveoli i.e you’re looking at the lung
- Large alveolar spaces b/c endothelial cells have been destroyed
- Fibrotic deposition (pink)
- Mononuclear cell infiltration ( looks like tons of black dots)
Describe the histological characteristics of chronic pyelonephritis.
Appearance of many black dots= mononuclear
What are the hallmark features of plasma cells? What do you assume if you see plasma cells?
- Nucleus= v. large, dense, & located on a single side
- Cell is large than the other lymphocyte
*IF you see PLASMA CELLS= CHRONIC INFLAMMATION
What are macrophages derived from?
- Circulating blood monocytes
- Once the monocyte exits the blood, it is a macrophage
*This is the key cell in chronic & granulomatous inflammation
What is the difference between monocytes & mononuclear cells?
Agranulocytes, also known as mononuclear leukocytes, are white blood cells with a one-lobed nucleus. They are characterized by the absence of granules in their cytoplasm, which distinguishes them from granulocytes.
- 2 categories:
1) Lymphocytes i.e. T, B & NK cells
2) Monocytes–>macrophages
What is a Kupffer cell?
Liver macrophages
What is an alveolar or pulmonary macrophage?
Macrophage in the lung
What is a macrophage in the bone?
Osteoclast
What is a macrophage in the brain?
Macroglia
When do monocytes emigrate to the site of injury?
Within 24-48 hours
Describe the histological features of activated macrophages. How do these differ from non-activated macrophages?
Activated=
- large i.e. increased size
- Pink
- Flat or epithelial-like or epitheloid
Non-activated=
- Small
What are the functional features of activated macrophages?
- Increased size
- increased numbers of lysosomes & lysosomal enzymes
*Activated macrophages have an increased ability to kill organisms
Describe the cell lineage of macrophages.
Stem cell
Monoblast
Monocyte= blood
Macrophage= tissue
What is the predominant cell type of inflammation after 48 hours?
Macrophages
What are the activation signals for macrophages?
- Cytokines–esp. IFN-gamma–secreted by activated T-cells & NK-cells
- Gamma interferon is the KEY player in the activation of macrophages, which is specifically secreted by Th1 cells & NK-cells
What is an exogenous sources of IFN-gamma production?
Bacterial endotoxin i.e. LPS
What causes activated macrophages to travel down a path of inflammation & tissue injury mediation vs. repair?
Inflammation & Tissue Injury= IFN-gamma
Repair= IL-4
What causes activated macrophages to persist in a chronic inflammatory state?
Continuous recruitment & local proliferation at the site of inflammation
What cytokines produced by macrophages mediate tissue injury?
IL-1
TNF-a
