The spleen's outer capsule is thin and can burst due to an infection or trauma.
An individual with no spleen is more susceptible to certain types of infections and may need antibiotic therapy indefinitely.
The structures encounter diseases in the body through the mouth.
The functions of the lymphatic system are summarized.
We are exposed to a lot of organisms in our environment.
Most innate defenses act quickly to detect and respond to pathogens.
Natural killer cells and phagocytes protect against infections very quickly.
With innate immunity, there is no recognition that an attacker has attacked before, and therefore no immunological "memory" is present for the attacker.
The skin, mucus, and urinary tracts are some of the physical barriers to invaders.
The outer layers of our skin are composed of dead cells that form a barrier.
Infections are one of the first concerns when the skin has been injured.
The mucus produced by the pharoahs is very strong.
The upper respiratory tract is lined with ciliated cells that sweep mucus and trapped particles up into the throat, where they can be swallowed or expectorated.
The vagina is home to many different types ofbacteria that take up vitamins and block binding sites that could be exploited by pathogens.
saliva, tears, milk, and mucus contain lysozyme, an enzyme that can lysebacteria, and the stomach has an acidic pH.
The inflammatory response occurs when tissues are damaged by a variety of causes.
redness, heat, swelling, and pain are some of the telltale signs of an inflammation.
Most of the signs are caused by capillary changes in the Page 622 damaged area.
Chemical mediators released by damaged cells cause capillaries to dilate and become more permeable.
The skin becomes warm due to increased blood flow.
The swelling of the tissues is caused by the increased permeability of the capillaries.
Other reactions to the injury can be accompanied by an inflammatory response.
Macrophages and dendritic cells are present in the tissues and can kill pathogens.
The inflammatory and other immune responses are stimulated by macrophages and dendritic cells.
A break in a blood vessel can be sealed with a blood clot.
White blood cells migrate from the bloodstream to damaged tissues when inflammation is present.
Once in the tissues, monocytes can differentiate into dendritic cells and macrophages, which are able to devour many pathogens and still survive.
The release of macrophages also stimulates the production and release of white blood cells in the red bone marrow.
Thebacteria are being engulfed by macrophage.
The body's scavengers are monocytes-derived macrophages.
The colorized scanning electron micrograph shows how they clean the body's fluids and tissues.
Chronic inflammation can become damaging to tissues if it persists.
Anti inflammatory drugs, such as aspirin, are used to treat chronic inflammation.
Inflammation is caused by inflammatory chemicals being released in the damaged area.
Inflammation can be absorbed into the bloodstream from the site of their production in damaged tissues.
Patients with certain diseases are frequently measured to assess levels of inflammation.
Some people think that certain immune mechanisms work better at higher body temperatures than at lower ones, and that certain germs may not survive as well at higher temperatures.
Both hypotheses are supported by experimental data and may be true.
The wisdom of using drugs to treat mild fevers can be questioned because of the fact that it appears to help the body fight off invaders more effectively.
The situation must be treated as an emergency because a body temperature higher than about 107degF can be fatal in children.
Other responses to the injury include inflammatory responses.
A break in a blood vessel can be sealed with the clotting system.
Antigens, chemical mediators, and dendritic cells move from the damaged tissue to the other side of the body.
There, the phagocytes interact with T cells and B cells to create an adaptive response to the infection.
Macrophage play an essential role in the healing response.
Several types of white blood cells are called phagocytic, which means they can digest large particles.
There are multiple ways of killingbacteria.
The neutrophil's cytoplasm is filled with granules that contain antimicrobial peptides and can digestbacteria.
Highly reactive free radicals, such as superoxide and hydrogen peroxide, are generated by other enzymes inside the neutrophil granules.
Some neutrophils die as the infections is being overcome.
The body is trying to get rid of a disease.
Dendritic cells are found in the skin, whereas macrophages are found in all sorts of tissues.
Both cell types break down the pathogens into smaller components.
T cells are responsible for triggering adaptive immune responses.
Natural killer (NK) cells are large, granular lymphocytes that kill virus-infected cells and cancer cells by cell-to-cell contact.
While adaptive defenses are still being activated, NK cells produce cytokines that promote immunity.
The major histocompatibility complex I is called MHC-I and is found on cells that lack self.
Some cancer cells that lack the MHC-I molecule may be killed by the NK cells, which cause them to commit suicide.
After stimulation, the number of NK cells do not increase because they do not recognize specific viral or tumor antigens.
In the blood, the proteins are present but must be activated by the pathogens to exert their effects.
The inflammatory response can be amplified by certain complement proteins, which can bind to mast cells and cause a release of histamine.
Increased activity of the immune system.
There is a chance that the pathogens will be killed by a macrophage.
The holes in the surface of somebacteria and viruses are caused by the formation of a membrane attack complex.
The fluids and salts enter the cell and cause it to burst.
When complement proteins in the blood are activated by an immune response, they form a membranes attack complex, which makes holes in the cell walls and allow fluids and salts to enter until the cell eventually bursts.