Role of the Macrophages

Role of the Macrophages

1. recognition & phagocytosis of foreign material such as microorganisms

2. removal of old or damaged cells from circulation

3. activation of immune response in B & T lymphocytes

The inflammatory response is a chronological reaction to a cell injury

1. it neutralizes & dilutes the agent that is causing inflammation

2. removes the necrotic materials

3. establishes environment that is suitable for repair & healing

Inflammation & Infection

1. inflammation is always present with infection, but infection not always present with inflammation

2. a person who is neutropenic may not have an inflammatory response

3. an infection is caused by an intrusion of tissues or cells by microbes ie. bacteria, fungi, or virus

4. the difference is that inflammation can be caused by non-living agents. ie. heat, radiation, trauma, or allergens

5. IF an infection is present it is from super-imposed invasion of microbes

6. the system of inflammation is basically the same regardless of injury agent or cause, non-specific response

7. the extent to which there is a response is based on the severity of the injury, the extent, and or how person's body is able to react.

8. the inflammatory response can be divided into a vascular response, formation of exudate, cellular response & healing

Vascular Response occurs after injury to a cell

1. arterioles in the area briefly undergo transient vasoconstriction

2. the tissues release histamine & kinins which result in vasodilation

3. the increased blood flow to area results in redness & heat

4. vasodilation & chemical mediators cause endothelial retraction which results in capillary permeability. It contains fluid with large amount of protein which leads to local pressure

5. the extra fluid from the capillaries is moved into tissues

6. the fluid is called fluid exudate and has 3 functions:

   a. provides nutrients necessary for healing

   b. it dilutes the bacterial toxins

   c. brings in cells necessary for phagocytosis

Outline for Inflammatory & Wound

The body has a variety of defense mechanisms that protect against injury & infection

These defenses are

1. the skin & mucous membranes (primary line of defense)

2. the mononuclear phagocyte system

3. the inflammatory response

4. the immune system Lemone 295-303

Mononuclear phagocyte system (MPS)

1. It is not a body system with particular tissues & organs

2. It consists of free (mobile) or fixed phagocytic cells

3. The macrophages of the liver, spleen, bone marrow, lungs, lymph nodes, & N.S. are all fixed phagocytes

4. The monocytes are in the blood and the macrophages in the connective tissue "histocytes" - mobile or wandering phagocytes

5. Monocytes & macrophages stem from bone marrow

6. Monocytes spend a couple of days in the blood & penetrate tissues & change into macrophages

7. Tissue macrophages are larger & more phagocytic than monocytes