Innate Defense System

* Healing: When the epidermis breaks away due to a minor cut or burn, the cells on the lower layers of the skin migrate upwards as a sheet. When two ends of the sheet meet, the cells stop growing due to a process called 'contact inhibition'. Thus, the epidermis is sealed and the skin returns to normal.

Proliferative phase occurs within a few days of injury in which cells that were involved in the battle need to tend to their wounds and the regenerate to restore itself to its formal glory as best as possible. The body’s way of restoring itself is through use of angiogenesis, granulation tissue formation, wound contraction and epithelialization. This combination acts of getting new blood vessels to the damage area, aid in the formation of cells to fill in the area which leads to scar tissue, allow the skin to flexible in the repair process and finally resurface the wound with new epithelial

When the body recognizes that bruising has occurred the body’s natural healing abilities take effect. The first thing that the body will do will be to release histamines to increase to permeability of the

The inflammation reaction to a skin cut is beneficial. When we have a skin cut or a trauma to the skin. Inflammation is a mechanism of defense; the body will release chemicals like histamine to promote capillary permeability and will increase the number of white blood cells to fight pathogens. This process will lead to healing the wound.

Plasma would carry white blood cells, red blood cells, and platelets to the injury site, which is the scrape on the hand. Platelets would attach with each other, building a blockade to stop blood flow at the injury site. White blood cells would attack and kill foreign substances that enter through the injury site and try to hurt the body. Red blood cells would provide oxygen at the injury site to help heal the injury, having that platelets have created a blockade.

For example, the signs and symptoms of wound infection could be confused with the inflammatory phase, while parts of the wound may be in the destructive phase, with other parts in the proliferative phase. Nevertheless, to recognise that the complex physiological process can be divided into distinct phases from the initial emergency response to injury through a process of repair and regeneration to complete healing helps the nurse in the clinical decision-making process.

Step3, Phagocytes engulf dead cells and cellular debris. Step4, Platelets move out of the capillaries to seal the wounded area. The implantation of a biomaterial initiates the inflammatory response in a sequence of events following the implantation from acute inflammation to chronic inflammation to granulation tissue. Acute inflammation lasts a few hours to days. Histamine release and blood vessels near the implantation site become dilated and leaky. Neutrophils and plasma protein “escape” into tissue. Neutrophils are also called poymorphonuclear leucocyte (PMN). Area around the injury becomes swollen and red due to the increase of blood flow. Major role of neutrophils is to phagocytose (engulf and eat dead cells) microorganisms and foreign mateirals. Neutrophils are short lived. Predominate during the first few days of inflammation. Chronic inflammation is the 2nd stage of healing process. Presence of monocytes and lymphocytes. Monocytes differentiate into macrophages to phagocytose particles and break it down into smaller fragments. If the device is large, frustrated phagocytosis will occur where macrophages become larger by fusion and foreign body giant cells will

Fifty-eight patients with 3rd degree burns were studied. Samples of eschar were taken from the center of the wounds between 2 and 46 days. Skin biopsies from 5 control patients were taken from surgical wounds immediately after the first incisions were made (1). The tissue samples were mounted, fixed and stained with hematoxylin and eosin. Some were used for immunohistochemistry to detect complement and CRP. These tissue sections were incubated with either polyclonal rabbit anti-human complement C3d at 1:2000 dilution or with a 1:400 dilution of monoclonal mouse anti-human CRP or with a 1:400 dilution of monoclonal mouse anti-human CD68 (to detect macrophages) or with a 1:500 dilution of polyclonal rabbit anti-human myeloperoxidase (to demonstrate neutrophils) (1). Control slides were not stained with primary antibody. The Cd3 and CRP levels were analyzed with a scoring system of 0-3 with 0 being negative and 3 being strongly positive (1). The macrophage and neutrophil levels were assessed by choosing 10 high powered fields (at 400x magnification) per section and counting the cells staining positively for CD68 and MPO respectively. The average number of cells per field was considered to be the score of the biopsy (1).

Phagocytes are attracted to the wound area; destroy bacteria present and clean up dead tissue. However, they can only operate at the edges of the wound where conditions are aerobic. The immune system reacts to the exotoxin by beginning the process of producing an antibody to destroy the toxin molecules. However, this process may take weeks, and the disease is likely to kill the person within this time period, if the wound and infection is

In an acute reaction, leukocytosis occurs as a result of increasing the number of circulating white blood cells to aid the immunity response. The movement of white blood cells to the site of injury occurs as a result of chemotaxis. Margination and emigration are the events that describe the action of circulating leukocytes from the blood to the injured tissue. To summarize, leukocyte margination is mediated by vasodilation and slowing of blood flow. Rolling results from initial interaction of leukocyte and endothelial adhesion molecules. There is an increase in expression of these molecules on cells as the cells are activated by inflammatory cytokines. Firm adhesion occurs following more adhesion molecule interaction and this interaction leads to emigration through the vessel wall (Akira & Kawai, 2012). Neutrophils arrive early to phagocytose microbes and cellular debris (Sadik, Kim & Luster, 2011). Monocytes travel in the blood and migrate to the injured tissue where they become macrophages. These cells are capable of engulfing greater quantities of foreign material and can move to the lymphatic system, where they prime specific immunity (Shi & Pamer,

My interest in biological sciences came from a strange source—injury. When I was in elementary school, there was never a time when I wasn’t injured somewhere on my body. Bruises, cuts, and Band-Aids were seemingly never ending. One time when I was riding my bicycle, I managed to trip over a stick and land on my knees, causing a deep abrasion on one of them. Instead of flinching or crying in pain, I intently observed in awe as my body worked to stop the bleeding. I closely examined the progress of cellular regeneration on my body, but I had so many unanswered questions. How does blood turn into scabs? Why do wounds become so sore? How does the body heal itself?

During the summer, my brother, Justin, obtained a cut on his hand. The cut occurred after he stuck his hand into a car motor while working and the fan proceeded to cut open his knuckles. The wound was around and inch and a half long and appeared to be very deep. I advised cleaning the wound with water and unscented soap. An alcohol base solution would also be helpful to disinfect and clean the wound to minimize the chance of infection. To dress the wound, we applied gauze and taped it as this is all we had without seeking medical attention.

Although the innate and adaptive immune systems both function to protect against invading organisms, they differ in a number of ways. The adaptive immune system requires some time to react to an invading organism, whereas the innate immune system includes defenses that, for the most part, are constitutively present and ready to be mobilized upon infection. Second, the adaptive immune system is antigen specific and reacts only with the organism that induced the response. In contrast, the innate system is not antigen specific and reacts equally well to a variety of organisms. Finally, the adaptive immune system demonstrates immunological memory. It “remembers” that it has encountered an invading organism and reacts more rapidly on subsequent

Innate immunity refers to nonspecific defence mechanisms that respond to an antigen's presence in the host body. These mechanisms include physical barriers such as skin, chemicals in the blood, and immune system cells that attack foreign cells in the body. The innate immune response is activated by chemical properties of the antigen.

The neutrophils are attracted by fibronectine and growth factors which leads to them performing their role of phagocytosis. Phagocytosis allows the neutrophils to engulf all the debris and bacteria that are in and surround the site therefore getting rid of foreign particles and allow a clean environment for the inflammation to being to happen. As a result of the phagocytosis happening this then leads to macrophages replacing neutrophils which come from immature monocytes which are stored in spleen, they secrete growth factors and cytokines which lead onto the next phase of the healing response which is the proliferation phase (Frederic H. Martni, Judi L. Natch, Edwin F. Bartholomew, 2014).